Revision of bush frogs, Raorchestes and Philautus (Amphibia: Anura: Rhacophoridae) from the northeast Indian biodiversity hotspot with description of thirteen new species

517 Revision of bush frogs, Raorchestes and Philautus (Amphibia: Anura: Rhacophoridae) from the northeast Indian biodiversity hotspot with description of thirteen new species Bitupan Boruah1, V. Deepak2,3,4, Abhijit Das1 1 Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand 248001, India 2 Museum of Zoology, Senckenberg Natural History Collections, Königsbrücker Landstraße 159, 01109 Dresden, Germany 3 The Natural History Museum, Cromwell Rd, South Kensington, SW7 5BD London, United Kingdom 4 Newcastle University, Newcastle NE1 7RU, United Kingdom https://zoobank.org/7C8226BF-FEA3-4EE2-9012-C0B859797028 Corresponding author: Abhijit Das ([email protected].in) Academic editor Uwe Fritz | Received 28 January 2025 | Accepted 21 October 2025 | Published 20 November 2025 Citation: Boruah B, Deepak V, Das A (2025) Revision of bush frogs, Raorchestes and Philautus (Amphibia: Anura: Rhacophoridae) from the northeast Indian biodiversity hotspot with description of thirteen new species. Vertebrate Zoology 75: 517–625. https://doi.org/10.3897/vz.75. e148133 Abstract Bush frogs currently in the genera Raorchestes and Philautus are poorly documented from northeast India when compared to the Western Ghats of southwestern India. They are morphologically cryptic, but variable in their acoustic repertoire and genetic divergence. We present a long-overdue revision of the bush frogs of northeast India by sampling 81 localities in eight Indian States (including nine type localities of known species) and by comparing historical (especially, type) material. Using an integrative approach that combines levels of divergence in mitochondrial DNA, a nuclear-encoded gene and comparing morphological and bioacoustic data, we demonstrate the existence of 13 new species, which are formally described here. In addition, based on the evidence from molecular and morphological data we synonymise four previously described species from this region. We resolve the taxonomic identities of three other frog species found in northeast India. After extensive survey across northeast India, we did not find a single specimen of the genus Philautus. The only species in this genus with ambiguous generic identity is P. dubius which requires further taxonomic investigation. Keywords Bioacoustics, cryptic species, Indo-Burma, Indochina, morphology, phylogeny, redescription, taxonomy Introduction The anuran family Rhacophoridae is represented by 473 species in 23 genera (Frost 2025). Members of this family are distributed throughout sub-Saharan Africa, South, Southeast and East Asia (Ellepola and Meegaskumbura 2023; Frost 2025). In Asia there are three genera of bush frogs/shrub frogs namely: Philautus Gistel, 1848, Pseudophilautus Laurent, 1943, and Raorchestes Biju et al., 2010. Within Rhacophoridae, these three genera can be Vertebrate Zoology 75, 2025, 517–625 | DOI 10.3897/vz.75.e148133 Copyright Bitupan Boruah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Boruah B et al.: Revision of bush frogs from northeast India 518 distinguished from other genera by their direct development or lecithotrophic tadpole and small to medium body size (maximum snout-vent length 65 mm) in adults (Bossuyt and Dubois 2001; Biju et al. 2010; Etter et al. 2021; Garg et al. 2021). There are currently 212 species of Asian bush/shrub frogs, 121 of which have been described in the last two decades. Species in this polyphyletic group were originally described under many rhacophorid and non-rhacophorid genera until Bossuyt and Dubois (2001) placed them in the genus Philautus. Subsequently, Li et al. (2009) resurrected the genus Pseudophilautus which currently has 78 species, distributed mostly in Sri Lanka, and an additional three species found in the Western Ghats and one species in the Eastern Ghats of India (Bharath et al. 2024). Biju et al. (2010) erected Raorchestes to treat a large radiation (82 species) of Asian bush frogs distributed in the Western Ghats, central, eastern and northeast India, Nepal, southern China, Myanmar, Thailand, Laos, Vietnam, Cambodia and Malaysia (Du et al. 2024; Frost 2025). Recent robust phylogenetic studies have not only described new species within the genus, but have also transferred species that were formerly allocated to other genera, such as Theloderma Tschudi, 1838 (Chen et al. 2020; Garg et al. 2021). Based on Biju et al. (2010), a few species from northeast India have been transferred to the genus Raorchestes, and a few doubtful species continue to be placed in the genus Philautus (Garg et al. 2021). At present, 15 species of bush frogs are known from northeast India under the genus Raorchestes [R. andersoni (Ahl, 1927), R. annandalii (Boulenger, 1906), R. asakgrensis Naveen, Chandramouli & Babu, 2024, R. garo (Boulenger, 1919), R. jadoh Warjri, Purkayastha, Lalremsanga & Das, 2025, R. jakoid Warjri, Purkayastha, Lalremsanga & Das, 2025, R. kempiae (Boulenger, 1919), R. manipurensis (Mathew & Sen, 2009), R. rezakhani AlRazi et al., 2020, R. sahai (Sarkar & Ray, 2006) and R. shillongensis (Pillai & Chanda, 1973)] and Philautus [P. dubius (Boulenger, 1882), P. kempii (Annandale, 1912), P. microdiscus (Annandale, 1912), P. namdaphaensis (Sarkar & Sanyal, 1985)]. Of these, 13 species have been described from northeast India (Fig. 1A; Table S1A). Out of these 13 species, 10 (R. asakgrensis, R. garo, R. jadoh, R. jakoid, R. manipurensis, R. sahai, R. shillongensis, P. dubius, P. microdiscus and P. namdaphaensis) are endemic to the region. Boruah et al. (2018) identified the phylogenetic position of R. shillongensis and redescribed the species and Naveen et al. (2024) redescribed R. garo and R. kempiae and generated some genetic data and added to the phylogenetic information. Most recently, Warjri et al. (2025) described two new species from Meghalaya. However, these studies relied primarily on single-locus datasets and geographically limited sampling. In contrast, comprehensive multi-locus phylogenetic approaches have been shown to be more effective in resolving taxonomic uncertainties (Chan et al. 2018, 2020). Additionally, most descriptions of the remaining species from northeast India are over a century old and based on a single specimen. Since the original descriptions, less effort was made to revisit the type localities of these species. Subsequently, many authors (Chanda 1994; Choudhury et al. 2002; Ao et al. 2003; Sarkar and Ray 2006; Sen and Mathew 2008; Mathew and Sen 2009, 2010; Sengupta et al. 2010; Sen et al. 2013; Saikia et al. 2016; Ohler et al. 2018; Purkayastha et al. 2020) reported or listed these species following the original description, although their taxonomic identities were not reassessed. Therefore, a comprehensive and systematic study of the bush frogs of northeast India is a long overdue. Thus, our present study aims to fill this gap by utilising morphological, molecular and acoustic data. Unlike the Raorchestes from the Western Ghats which are diverse in body size (16–50.5 mm), colouration and ecomorphology (Biju and Bossuyt 2009; Zachariah et al. 2011; Vijayakumar et al. 2014; Garg et al. 2021), the species from northeast India are more conservative in morphology, with a less difference in range of body size (13–28 mm) and colouration, and occupy similar ecological niches. However, there are multiple geographic barriers and various habitat types in northeast India where several small amphibian and reptile species have diversified (Agarwal et al. 2014; Mahony et al. 2020; Boruah et al. 2024). The effectiveness of using bioacoustic evidence in systematic studies revealing cryptic anuran species has been highlighted for other frogs (Prasad et al. 2020; Trofimets et al. 2024; Vences et al. 2024). Raorchestes species are highly vocal, with males emitting distinctive advertisement calls that have been proven useful for taxonomic classification (Garg et al. 2021). However, information available on the bioacoustics of bush frogs from northeast India is limited. Between the years 2016 and 2024, we sampled across northeast India (see Fig. 1B), collecting multiple populations of bush frogs with particular focus on topotypic material. In this revision we reassess the phylogenetic relationships of the bush frogs of northeast India, resolve previous ambiguous species identifications and describe 13 new species based on molecular data, morphological characters, and acoustics. Materials and methods Field survey and sample collection We collected 204 specimens from 81 localities across eight Indian states, namely Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and West Bengal during 2016–2024 (Fig. 1B; Table S1B). Specimens were located visually at night using a handheld torchlight or by following the calls of male frogs. Collected specimens were photographed in life and then euthanized using tricaine methanesulfonate (MS-222). Specimens were fixed in 4% formalin and stored in 70% ethanol after rinsing in water. Prior to fixation, tissue samples were collected from thigh muscle or liver and stored in absolute ethanol for DNA extraction. Collected specimens were deposited in the repository at the Wildlife Institute of India, Dehradun. Vertebrate Zoology 75, 2025, 517–625 519 Figure 1. Map of northeast India showing distribution. A Type localities of previously described bush frog species from northeast India, Indochina and Indo-Burma; B sampling localities for bush frogs during this study between 2016 and 2024 (see Table S1 for locality details). Political boundaries of neighbouring countries are marked with black lines and state boundaries within the political boundary of India are marked with grey lines. Boruah B et al.: Revision of bush frogs from northeast India 520 DNA extraction and amplification We extracted genomic DNA from tissue samples using Qiagen DNeasy Blood and Tissue Kit following the manufacturer’s instructions. We amplified partial sequences of three mitochondrial genes, 16SrRNA (16S; 560 base pairs (bp)), cytochrome b (cyt b; 610 base pairs) and cytochrome c oxidase subunit I (COI; 680 base pairs), and one nuclear gene, rhodopsin (RHO; 320 base pairs) using previously published primers and protocols (Table S2). Amplified PCR products were run on a 2% agarose gel and viewed under UV transilluminator. The purified PCR products were sequenced in both directions on an Applied Biosystems Genetic Analyzer 3500 XL using BigDye v3.1 kits. The newly generated sequences in this study were deposited in DNA Data Bank of Japan (DDBJ) with the registration numbers LC896952, LC896953, and LC898195– LC898646 (Table S3). Phylogenetic analyses We conducted two phylogenetic analyses, one using concatenated dataset of mitochondrial and nuclear genes consisting of a total of 2034 bp (16S 556 bp, cyt b 571 bp, COI 617 bp and RHO 290 bp) and one using concatenated dataset of only mitochondrial genes. Bidirectional sequences were manually checked using the CHROMAS v2.6.6 software (http://technelysium.com.au/wp/chromas) and aligned using ClustalW (Thompson et al. 1994) with default prior settings implemented in MEGA v7.1 (Kumar et al. 2016). For the protein-coding genes, we checked for unexpected stop codons by translating the sequence into amino acids in MEGA v7.1. We aligned the newly generated sequences with sequences downloaded from GenBank (Benson et al. 2007) (Table S3). We used six Raorchestes species, three each from the northern and southern clades from the Western Ghats and two species of Pseudophilautus as outgroups following Garg et al. (2021). We performed maximum likelihood analyses using the GUI version of the IQTREE (Nguyen et al. 2015), implemented in PHYLOSUITE (Zhang et al. 2020) one on the concatenated dataset of mitochondrial and nuclear genes and another one on concatenated dataset of only mitochondrial genes. We partitioned the two datasets by gene and codon position using MODELFINDER (Kalyaanamoorthy et al. 2017) to find the best-fit partitions and models of sequence evolution for each partition (Table S4). We also performed a Bayesian inference (BI) analysis for the concatenated dataset on mitochondrial and nuclear genes using the program MrBayes 3.2 (Ronquist et al. 2012), with default prior settings. The same data set used for the maximum likelihood (ML) analysis was partitioned by codon positions using PartitionFinder v1.1.1 (Lanfear et al. 2012) with default settings to find the best-fit model of sequence evolution (Table S4A). Four separate runs were set up with eight Markov chains each initiated from random trees and allowed to run for 10 million generations, sampling every 100 generations. Analyses were terminated when the standard deviation of the split frequencies was less than 0.001, the first 25% of trees were discarded as burn-in, and trees were constructed using a 50% majority consensus rule. We obtained the ESS values using TRACER v1.6 (Rambaut et al. 2018) and confirmed greater than 200 for the priors. Support for the internal branches for the ML and BI was quantified using 10,000 pseudoreplicates (ultrafast bootstrap UFB) and posterior probability (PP), respectively. Branch supports (UFB and PP) higher than 95 (UFB: see Minh et al. 2013) and >0.95 were considered as strong support. The resulting tree was edited in FigTree v.1.4.4 (http://tree. bio.ed.ac.uk/software/figtree). Morphological examination of the type series of Raorchestes sahai suggested that they did not belong to the genus Raorchestes (see below in taxonomic conclusions section). In order to confirm the identity of this species, we performed a BLAST search (Altschul et al. 1990) on the NCBI BLAST website (http://blast.ncbi.nlm.nih. gov) for the sequences (16S) generated from samples that were collected from the type locality and are morphologically similar to the type series. These topotypic sequences showed similarity to another Rhacophorid genus rather than Raorchestes and Philautus. To further confirm the identity of the species, the newly generated sequences were aligned with 34 samples from GenBank representing 15 rhacophorid genera and Buergeria oxycephala (Schlegel, 1858) was used as an outgroup (Benson et al. 2007; Table S5). For this data set of 526 base pairs (16S), we performed a third ML analysis using the GUI version of IQTREE (Nguyen et al. 2015) implemented in PHYLOSUITE (Zhang et al. 2020). Species delimitation To delineate putative species boundaries for northeast Indian, Indo-Burmese and Indochinese Raorchestes, we performed two different species delimitation methods namely: Multi-Rate Poisson Tree Processes (mPTP) (Kapli et al. 2017) and Assemble Species by Automatic Partitioning (ASAP) (Puillandre et al. 2021). ASAP is a distance-based species delimitation method that identifies putative species boundaries based on pairwise genetic distances. Whereas mPTP accounts for varying coalescent rates among clades, enabling it to reflect different levels of intraspecific genetic diversity across lineages. These methods have been recently used in amphibian taxonomy (Oswald et al. 2023; Carne and Vieites 2024; Arias et al. 2025). The concatenated mitochondrial dataset (16S + cyt b + COI) was used for both the delimitation analyses. The ML tree inferred from concatenated mitochondrial dataset was further used as the input tree for mPTP in a web-server accessible at http://mptp.h-its.org and the following functions were used: MCMC = 10,000,000, minimum branch length = minbr_auto. The same concatenated mitochondrial dataset was used for ASAP in a web-server accessible at https://bioinfo.mnhn.fr/abi/public/asap. For the ASAP analysis, the substitution model of p distances was used to compute the distances along with the default values for other parameters. Vertebrate Zoology 75, 2025, 517–625 521 Uncorrected pairwise distances (p distances) were calculated in MEGA v7.1 with pairwise deletion of missing data and gaps for each mitochondrial gene (16S, cyt b and COI) separately. The pairwise genetic distances for the 16S dataset were used as a guide for lineage delimitation. The genetic divergences (16S) were considered as low (1% to 2%), moderate (>2% to <4%) and high (4 % to 6%) following Vijayakumar et al. (2014). Morphological examination Morphometric measurements were taken to the nearest 0.1 mm using a digital slide calliper (Mitutoyo CD6˝CSX). Metric and meristic characters were examined using a stereomicroscope (Olympus SZX10). Sex and maturity were determined based on either presence of vocal sac and nuptial pad in males, or by examination of gonads through a ventrolateral incision. Measurements and associated terminology followed Boruah et al. (2023a), unless otherwise stated. The following measurements were taken: SVL (snout-vent length), HW (head width at angle of jaw), HL (head length from rear of mandible to tip of snout), SL (snout length from tip of snout to anterior orbital margin), EN (distance from front of eye to nostril), NS (distance from nostril to tip of snout), IN (internarial distance), EL (horizontal eye length between orbital margins), IUE (shortest inter-upper eyelid width between upper eyelids), UEW (maximum upper eyelid width), IFE (internal front of eyes, shortest distance between anterior orbital margins), IBE (internal back of eyes, shortest distance between posterior orbital margins), HTYD (maximum horizontal tympanum diameter), MN (distance between rear of mandible and posterior border of nostril), MAE (distance between rear of mandible and anterior border of orbit (eye)), MPE (distance between rear of mandible and posterior border of orbit (eye)), FAL (forearm length from flexed elbow to base of outer palmar tubercle), HAL (hand length from base of outer palmar tubercle to tip of third finger), AG (distance between axilla and groin), TL (thigh length from vent to knee), TBL (tibia length from knee to heel), TarL (tarsus length from tibio-tarsal articulation to base of inner metatarsal tubercle), FOL (foot length from base of inner metatarsal tubercle to tip of fourth toe), FL (finger length from tip of finger to its base where it joins adjacent finger), TOL (toe length from tip of toe to its base where it joins adjacent toe), digit (finger and toe) numbers are represented by Roman numerals I–V (inside to outside), FD (disc width of fingers), TD (disc width of toes). All measurements in the text are given in millimetres. Measurements were taken from the right side of the specimen. We also examined the skin texture of the collected specimens broadly categorised as: tubercles (small dermal projection with blunt tip), spinules (small dermal projection with sharply pointed tip) and granules on ventral side of head, abdomen and limbs. We collated body size (SVL) data for other congeners from northeast India and Indochina and Indo-Burma (Table S6). The data were plotted using ggplot2 (Wickham 2016) in the program R v.4.4 (R Core Development Team 2021). We compared newly described species with the congeners known from northeast India and Southeast Asia and the redescribed species using original descriptions. Our morphological comparisons were based on measurements, skin texture, snout shape and colour patterns of the genotyped specimens included in the phylogenetic tree ( Table 1A, B). Commonly used ratios for species diagnosis and comparisons in this study were 1) head length vs. head width, 2) snout length vs. eye length, 3) snout length vs. inter-upper eyelid width, 4) inter-upper eyelid width vs. eye length, 5) internarial distance vs. upper eyelid width, and 6) thigh length vs. tibia length. Multivariate analyses We used Principal Component Analysis (PCA) to assess the overall morphological variation between different populations in the software R (R Core Team 2021) using the R package MASS (Venables and Ripley 2002). For this analysis, we used 38 morphometric variables of 176 individuals collected from 81 localities across northeast India. We excluded females, sub-adults, and individuals of which characters were damaged or not available. We used the GroupStruct R package (Chan and Grismer 2022) to calculate and account for allometric effects in the morphometric dataset, following the allometric equations described by Thorpe (1975, 1983). This is to avoid size dependent intercorrelation effects, prior to conducting PCA between the putative taxa without making a priori assumptions about groupings. Morphometric data were analysed in the software R, and the package ggplot2 was used to prepare plots (Wickham 2009). The results were plotted group wise except for R. annandalii, R. mindat Dost et al., 2025 and two putative species with low nodal support. These four species were plotted along with other species from their closest group. We ran another PCA using eight morphometric measurements (SVL, IUE, UEW, EL, HL, HW, TL, and TBL) out of the 38 morphometric measurements which were also available for R. garo (ZSI19187) and R. kempiae (ZSI18859) types, to determine the morphospace of these types in relation to the newly collected material of the two species. Bioacoustic recording and analysis We recorded vocalisations in the field using a digital audio recorder (Marantz PMD 620 MK–II) with a unidirectional handheld microphone (Sennheiser MKH 416). Calls were recorded at a distance of approximately 30–50 cm from the calling male. These calling individuals were collected and DNA sequences of the same individuals were used for subsequent phylogenetic analyses. We used RAVEN PRO v.1.5 (http://www.birds.cornell.edu/raven) to visualise and analyse the acoustic properties (fast Fourier transform, width 1024 samples, Hann window with 50% overlap, 49.1 Hz resolution and 3db filter bandwidth). The acoustic properties and terminology follow Köhler Boruah B et al.: Revision of bush frogs from northeast India 522 Table 1A. Morphological comparison of Raorchestes species included in this study given as mean ± SD (range). NA=data not available. Species SVL in male (mm) SVL in female (mm) Snout Shape (dorsal view) HL/HW SL/EL SL/IUE IUE/EL Nostril position relative to eye and snout UEW/IN EL/HL HTYD/EL R. andersoni 18.75±7.42 (13.5–24.0) NA NA HL<HW NA NA IUE<EL closer to snout tip NA NA 0.25 R. annandalii 18.58±0.85 (17.3–19.6) 20.34±1.12 (18.9–21.6) rounded or sub ovoid 1.0±0.01 (0.98–1.01) (1.05±0.07 (0.96–1.15) 1.1±0.1 (0.97–1.23) 0.95±0.06 (0.81–1.0) closer to eye or equidistant 0.76±0.06 (0.65–0.84) 0.38±0.02 (0.35–0.42) 0.22±0.15 (0.25–0.36) R. cinerascens nov. comb. 16 NA rounded NA SL<EL SL=IUE NA NA NA NA NA R. dulongensis 16.7±2.0 (15.0–19.0) NA obtusely pointed 1.06±0.01 (1.05–1.07) 1.0±0.04 (0.97–1.04) 1.07±0.08 (1.0–1.15) 0.94±0.09 (0.87–1.04) closer to snout tip 0.76±0.05 (0.71–0.8) 0.43±0.04 (0.4–0.47) 0.49±0.07 (0.43–0.57) R. garo 24.54±1.8 (19.9–26.9) 26.9 rounded or sub ovoid 0.95±0.04 (0.91–1.06) 0.93±0.06 (0.81–1.03) 1.11±0.07 (0.96–1.28) 0.84±0.06 (0.74–0.94) closer to snout tip or equidistant 0.86±0.07 (0.72–1.0) 0.41±0.02 (0.36–0.46) 0.24±0.07 (0.21–0.34) R. hekouensis 17.0±0.7 (16.1–17.5) 21.1 rounded 0.9±0.05 (0.82–0.95) 0.77±0.19 (0.55–0.96) 0.85±0.19 (0.61–1.04) 0.9±0.04 (0.85–0.96) NA 0.79±0.11 (0.65–0.9) 0.45±0.05 (0.41–0.53) 0.5±0.09 (0.35–0.6) R. hillisi 16.4±1.0 (15.9–17.7) 17.5 rounded 1.13±0.08 (1.03–1.25) 1.21±0.08 (1.09–1.33) 1.21±0.06 (1.14–1.35) 1.0±0.07 (0.91–1.1) closer to snout tip 0.78±0.06 (0.69–0.88) 0.31±0.02 (0.69–0.88) 0.37±0.04 (0.32–0.43) R. huanglianshan 18.2± 0.8 (17.0–19.6) 21.5 rounded 0.98±0.01 (0.95–1.0) 1.18±0.09 (1.0–1.33) 1.08±0.08 (0.96–1.22) 1.09±0.11 (0.95–1.28) closer to snout tip 0.73±0.05 (0.65–0.84) 0.35±0.02 (0.30–0.38) 0.40±0.05 (0.33–0.5) R. jadoh 13.8± 0.23 (14.0–13.6) NA rounded 0.55±0.02 (0.53–0.57) 1.7 1.37 1.24 closer to snout tip 0.80±0.05 (0.77–0.83) 0.43 — R. jakoid 20.0± 2.21 (18.4–21.6) NA rounded 0.78±0.05 (0.74–0.81) 1.35±0.1 (1.34–1.36) 1.27±0.24 (1.1–1.4) 1.08±0.2 (0.94–1.2) closer to snout tip 0.78±0.02 (0.77–0.79) 0.32±0.04 (0.29–0.34) — R. kempiae 21.13±1.57 (17.8–22.9) 23.15±0.21 (23.0–23.3) rounded to sub ovoid or pointed 0.97±0.03 (0.91–1.01) 0.97±0.06 (0.82–1.04) 1.18±0.04 (1.12–1.28) 0.82±0.06 (0.71–0.93) closer to snout tip or equidistant 0.82±0.09 (0.67–0.92) 0.4±0.02 (0.36–0.42) 0.27±0.03 (0.22–0.34) R. leiktho 15.77±0.06 (15.7–15.8) NA rounded 1.00±0.08 (0.91–1.08) 1.07±0.2 (0.89–1.29) 1.19±0.09 (1.14–1.29) 0.9±0.11 (0.79–1.0) closer to snout tip 0.83±0.22 (0.67–1.08) 0.44±0.05 (0.4–0.5) 0.32±0.07 (0.25–0.38) R. longchuanensis 17.8–23.9 NA rounded HL=HW NA NA IUE>EL NA NA NA NA R. malipoensis 16.8±1.0 (14.6–17.7) 18.8±0.4 (18.3–19.3) obtusely pointed 0.87±0.08 (0.74–1.0) 1.0±0.14 (0.83–1.23) 0.84±0.14 (0.62–1.0) 1.20±0.12 (1.0–1.38) closer to snout tip 0.69±0.11 (0.54–0.86) 0.38±0.06 (0.30–0.5) 0.59±0.08 (0.5–0.71) R. menglaensis 18.87±1.27 (16.6–21.6) 19.7±1.13 (18.9–20.5) rounded 1.0±0.24 (1–1.18) 1.04±0.26 (1.03–1.34) 1.1±0.27 (1.0–1.28) 0.9±0.22 (0.84–1.08) closer to snout tip 0.78±0.19 (0.68–0.95) 0.33±0.8 (0.30–0.38) 0.29±0.08 (0.24–0.39) R. parvulus 17.88±0.69 (17.0–18.6) 23.0 rounded 1.01±0.03 (0.98–1.05) 0.95±0.16 (0.70–1.08) 1.1±0.15 (0.88–1.24) 0.86±0.03 (0.8–0.88) closer to snout tip or equidistant 0.94±0.13 (0.7–1.0) 0.41±0.4 (0.36–0.45) 0.29±0.09 (0.23–0.25) R. rezakhani 20.25±0.86 (18.8–21.0) NA rounded 0.71±0.14 (0.64–0.95) 0.9±0.07 (0.83–1.0) 1.04±0.14 (0.94–1.25) 0.86±0.05 (0.8–0.9) closer to snout tip or equidistant 0.9±0.04 (0.85–0.95) 0.54±0.07 (0.41–0.59) 0.43±0.06 (0.33–0.48) R. shillongensis 17.02±1.51 (13.9–20.4) 18.52±1.56 (15.1–21) rounded to sub ovoid or nearly pointed 0.95±0.04 (0.92–1.0) 0.99±0.05 (0.93–1.05) 1.13±0.04 (1.08–1.16) 0.88±0.05 (0.81–0.93) closer to snout tip or equidistant 0.83±0.06 (0.76–0.89) 0.4±0.03 (0.36–0.44) 0.29±0.05 (0.22–0.33) R. tytthus nov. comb. NA 20.9–21.2 rounded HL=HW SL>EL SL<IUE IUE>EL closer to snout tip IN>UEW NA NA R. yadongensis 20.3±2.7 (17.8–24.1) NA obtusely pointed 0.71±0.2 (0.51–0.9) 1.01±0.02 (1.0–1.03) 0.74±0.09 (0.61–0.82) 1.38±0.17 (1.27–1.63) closer to snout tip 1.04±0.08 (1.0–1.17) 0.57±0.08 (0.44–0.81) 0.32±0.04 (0.26–0.35) R. arunachalensis sp. nov. 23.57±1.87 (19.6–26.3) 25.0±3.82 (22.3–27.7) rounded to sub ovoid 0.98±0.03 (0.92–1.03) 0.9±0.06 (0.8–1.05) 1.13±0.07 (1.03–1.25) 0.8±0.05 (0.67–0.89) closer to snout tip 0.93±0.09 (0.71–1.04) 0.41±0.02 (0.38–0.45) 0.27±0.04 (0.21–0.34) R. barakensis sp. nov. 18.92±1.17 (16.7–21.0) NA rounded to sub ovoid 0.98±0.04 (0.89–1.02) 0.95±0.05 (0.82–1.04) 1.12±0.09 (0.96–1.27) 0.85±0.05 (0.72–0.96) closer to snout tip or equidistant 0.8±0.05 (0.7–0.91) 0.41±0.02 (0.38–0.45) 0.29±0.05 (0.19–0.38) Vertebrate Zoology 75, 2025, 517–625 523 Species SVL in male (mm) SVL in female (mm) Snout Shape (dorsal view) HL/HW SL/EL SL/IUE IUE/EL Nostril position relative to eye and snout UEW/IN EL/HL HTYD/EL R. boulengeri sp. nov. 18.18±0.68 (17.5–19.1) NA rounded 1.0±0.02 (0.98–1.02) 0.97±0.06 (0.89–1.04) 1.15±0.14 (1.04–1.35) 0.85±0.05 (0.77–0.88) equidistant 0.8±0.04 (0.75–0.85) 0.41±0.03 (0.38–0.45) 0.31±0.03 (0.28–0.35) R. dibangensis sp. nov. 20.7±1.56 (19.6–21.8) NA rounded 1.0±0.02 (0.96–1.03) 0.93±0.04 (0.86–1.0) 1.12±0.06 (1.03–1.24) 0.83±0.04 (0.77–0.91) closer to snout tip 0.96±0.07 (0.81–1.04) 0.37±0.03 (0.35–0.39) 0.24±0.05 (0.21–0.28) R. eaglenestensis sp. nov. 21.96±1.24 (18.8–23.6) 22.35±0.64 (21.9–22.8) rounded to sub ovoid 0.99±0.04 (0.94–1.07) 0.93±0.06 (0.86–1.07) 1.02±0.04 (0.97–1.1) 0.91±0.05 (0.84–0.97) closer to snout tip or equidistant 0.84±0.12 (0.5–0.92) 0.41±0.02 (0.37–0.43) 0.28±0.04 (0.19–0.33) R. mindat 17.7±0.61 (16.7–18.3) NA rounded 0.97±0.07 (0.88–1.07) 0.98±0.09 (0.92–1.18) 1.16±0.35 (0.92–1.9) 0.89±0.19 (0.5–1.05) closer to snout tip or equidistant 0.73±0.09 (0.6–0.84) 0.4±0.03 (0.35–0.43) 0.32±0.07 (0.27–0.46) R. khonoma sp. nov. 19.23±2.43 (16.9–22.0) NA rounded 0.98±0.03 (0.94–1.0) 0.97±0.04 (0.93–1.0) 0.99±0.05 (0.94–1.04) 0.98±0.02 (0.96–1.0) equidistant 0.94±0.08 (0.75–0.91) 0.4±0.01 (0.39–0.40) 0.33±0.02 (0.31–0.35) R. lawngtlaiensis sp. nov. 18.9±1.13 (18.1–19.7) NA rounded 0.96±0.01 (0.95–0.97) 0.83 1.07±0.03 (1.04–1.09) 0.78±0.03 (0.76–0.8) equidistant 0.95 0.44±0.03 (0.42–0.46) 0.22±0.02 (0.21–0.23) R. magnus sp. nov. 24.37±1.71 (22.5–27.4) 26.95±2.05 (25.5–28.4) rounded to sub ovoid 1.0±0.02 (0.96–1.03) 0.93±0.04 (0.86–0.97) 1.12±0.06 (1.03–1.24) 0.83±0.03 (0.77–0.91) closer to snout tip 0.96±0.07 (0.81–1.04) 0.4±0.02 (0.38–0.43) 0.28±0.04 (0.21–0.36) R. mawsynramensis sp. nov. 17.26±0.99 (16.0–18.7) 20 rounded 0.97±0.03 (0.92–1) 0.93±0.06 (0.87–1) 1.07±0.06 (0.96–1.15) 0.87±0.06 (0.8–0.96) equidistant 0.77±0.09 (0.62–0.89) 0.41±0.01 (0.38–0.43) 0.29±0.04 (0.24–0.37) R. monolithus sp. nov. 19.57±1.07 (17.9–20.6) NA rounded 0.94±0.03 (0.89–0.97) 0.97±0.05 (0.89–1.0) 0.99±0.03 (0.96–1.04) 0.98±0.03 (0.93–1.0) equidistant 0.77±0.08 (0.67–0.89) 0.4±0.02 (0.38–0.43) 0.24±0.12 (0.22–0.32) R. narpuhensis sp. nov. 19.81±0.87 (18.0–21.1) 23.1 sub ovoid to nearly acute 0.99±0.03 (0.94–1.01) 0.94±0.07 (0.81–1.03) 1.09±0.07 (0.96–1.21) 0.86±0.04 (0.8–0.93) closer to snout tip 0.82±0.1 (0.68–0.95) 0.41±0.02 (0.39–0.46) 0.16±0.12 (0.19–0.31) R. nasuta sp. nov. 18.6±1.16 (17.0–19.9) NA acute 1.06±0.05 (1.03–1.11) 1.02±0.02 (1–1.04) 1.09±0.05 (1.04–1.17) 0.93±0.03 (0.88–0.96) equidistant 0.81±0.03 (0.76–0.86) 0.38±0.01 (0.37–0.39) 0.31±0.02 (0.29–0.31) R. orientalis sp. nov. 18.67±1.49 (14.6–20.8) 20.85±1.48 (19.8–21.9) rounded or sub ovoid 0.99±0.04 (0.9–1.07) 0.99±0.05 (0.92–1.07) 1.14±0.1 (0.96–1.32) 0.88±0.08 (0.73–1.04) closer to snout tip or equidistant 0.81±0.1 (0.64–0.95) 0.39±0.02 (0.35–0.42) 0.28±0.06 (0.21–0.41) Table 1B. Morphological comparison of Raorchestes species included in this study given as mean ± SD (range). NA=data not available. Species Nuptial pad TBL/TL TL/SVL Skin on dorsum Concave stripes on back Pattern on groin Mid dorsal line Bands on hindlimbs Pattern on abdomen White band on interorbital space References R. andersoni NA NA NA scattered tubercles absent (?) large dark irregular spot with two light spots NA single band brown punctuations with yellow granules pale yellow bands may be present or absent Anderson (1978), Wu et al. (2021) R. annandalii F1 0.96±0.02 (0.93–1.0) 0.5±0.02 (0.48–0.54) scattered tubercles present absent absent one or three bands (outer two bands may be faint) whitish spots present or absent This study R. cinerascens nov. comb. NA TL>TBL NA scattered tubercles present a dark spot partially encircled by light tinge absent three bands no pattern absent Stoliczka (1870), this study Boruah B et al.: Revision of bush frogs from northeast India 524 Species Nuptial pad TBL/TL TL/SVL Skin on dorsum Concave stripes on back Pattern on groin Mid dorsal line Bands on hindlimbs Pattern on abdomen White band on interorbital space References R. dulongensis absent 0.96±0.08 (0.88–1.03) 0.49±0.03 (0.46–0.52) numerous tubercles present dark patches between two light patches present or absent three bands dark-brown and white spots absent Wu et al. (2021) R. garo F1 0.96±0.03 (0.91–1.01) 0.51±0.02 (0.46–0.54) moderate to heavy spinules; may be intermixed with blunt tubercles absent (hourglass shaped marking may be present) dark patches with or without light spots present or absent three bands pale-cream coloured blotches present or absent present or absent Boulenger (1919), this study R. hekouensis F1 and F2 0.81 (data available only for holotype) 0.53 (data available only for holotype) numerous tubercles present dark patches between two light patches present or absent three bands small black spots and white tubercles absent Du et al. (2024) R. hillisi F1 1.03±0.05 (0.98–1.12) 0.46±0.03 (0.42–0.5) scattered tubercles present a dark blotch present or absent three bands whitish spots absent Jiang et al. (2020) R. huanglianshan F1 0.98±0.03 (0.93–1.0) 0.44±0.02 (0.41–0.50) scattered tubercles present a dark blotch present or absent single band whitish spots absent Jiang et al. (2020) R. jadoh F1 1.13±0.1 (1.06–1.2) 0.49±0.01 (0.48–0.49) small warts scattered present — absent 1 (?) no pattern absent Warjri et al. (2025) R. jakoid F1 1.19±0.15 (1.08–1.3) 0.40±0.02 (0.38–0.42) small warts scattered present — absent 3 (?) no pattern absent Warjri et al. (2025) R. kempiae F1 0.98±0.03 (0.95–1.07) 0.51±0.02 (0.48–0.55) spinules intermixed with tubercles absent or faint a short dark stripe present or absent three bands but except middle bar, outer two bands barely visible no pattern absent Boulenger (1919), this study R. leiktho F1 1.03±0.06 (0.98–1.09) 0.51±0.04 (0.47–0.55) numerous spinules Absent (a pair of anteriorly merged stripes present) a short brownish olive bar absent one or three bands no pattern present or absent Köhler et al. (2025) R. longchuanensis F1 NA NA NA absent or indistinct NA NA NA NA NA Jiang et al. (2020), Wu et al. (2021), Huang et al. (2023) R. malipoensis F1 1.08±0.09 (0.94–1.21) 0.46±0.04 (0.42–0.54) small tubercles present present dark patches absent three bands white and black flecks absent Huang et al. (2023) R. menglaensis F1 0.98±0.24 (1.0–1.09) 0.45±0.11 (0.40–0.51) scattered tubercles present a dark blotch present or absent three bands whitish spots absent Jiang et al. (2020) R. parvulus NA 1.04±0.04 (0.99–1.1) 0.45±0.01 (0.43–0.46) scattered spinules present dark marbling enclosing a light blotch absent one on thigh and one or two on tibia brown and white mottling absent Boulenger (1893), Köhler et al. (2025) R. rezakhani F1 0.94±0.06 (0.85–0.99) 0.52±0.04 (0.48–0.59) scattered tubercles present short dark stripe absent three bands black or white spots absent Al-Razi et al. (2020), this study Vertebrate Zoology 75, 2025, 517–625 525 Species Nuptial pad TBL/TL TL/SVL Skin on dorsum Concave stripes on back Pattern on groin Mid dorsal line Bands on hindlimbs Pattern on abdomen White band on interorbital space References R. shillongensis F1 0.92±0.02 (0.89–0.94) 0.48±0.01 (0.47–0.50) tubercles moderate to heavy present (rarely hour-glass shaped patch) dark patch with light crownshaped mark or diffused dark patch absent one broad band or three but outer two may be diffused/ indistinct white and black blotches present or absent absent This study R. tytthus nov. comb. NA TL>TBL NA scattered tubercles present enlarged light patch absent single band irregular dark and light spots absent Smith (1940), this study R. yadongensis F1 NA NA small tubercles present present (faint) NA absent single indistinct band white patches absent Zhang et al. (2022) R. arunachalensis sp. nov. F1 0.96±0.02 (0.92–1.0) 0.54±0.02 (0.51–0.58) moderate to heavily tuberculated; may be intermixed with spinules present dark and light patches absent three bands white blotches present or absent present or absent This study R. barakensis sp. nov. F1 0.95±0.03 (0.9–0.99) 0.52±0.03 (0.47–0.57) dense spinules present absent absent three bands no pattern absent This study R. boulengeri sp. nov. F1 0.93±0.03 (0.9–0.97) 0.51±0.01 (0.49–0.51) dense spinules present dark and light patches absent three bands (faint) whitish spots absent This study R. dibangensis sp. nov. F1 0.94±0.01 (0.93–0.94) 0.49±0.01 (0.48–0.50) dense spinules on middle of back present (indistinct) absent absent two bands (faint) whitish spots present or absent This study R. eaglenestensis sp. nov. F1 0.96±0.02 (0.92–0.99) 0.51±0.03 (0.48–0.57) distinct tubercles present absent absent three bands white blotch present or absent absent This study R. mindat F1 1.03±0.12 (0.91–1.25) 0.46±0.04 (0.41–0.52) dense spinules present (Indistinct) enlarged dark and light patches absent one or three bands whitish spots absent Köhler et al. (2025), this study R. khonoma sp. nov. F1 0.94±0.02 (0.92–0.96) 0.49±0.02 (0.47–0.51) scattered tubercles absent or faint dark and light patches absent single band white spots with or without black spots absent This study R. lawngtlaiensis sp. nov. F1 0.93±0.01 (0.92–0.94) 0.5±0.01 (0.49–0.51) moderately dense spinules present dark band with light edge absent single band whitish spots absent This study R. magnus sp. nov. F1 0.95±0.03 (0.92–1.01) 0.52±0.02 (0.48–0.55) spinules intermixed with tubercles present enlarged dark patch present or absent three bands dark brown blotches present or absent present or absent This study R. mawsynramensis sp. nov. F1 0.94±0.02 (0.9–0.96) 0.49±0.02 (0.48–0.52) dense spinules present dark patches absent three bands (faint) whitish spots absent This study R. monolithus sp. nov. F1 0.89±0.01 (0.87–0.9) 0.49±0.02 (0.47–0.52) scattered tubercles barely visible enlarged dark patch absent single band whitish spots absent This study Boruah B et al.: Revision of bush frogs from northeast India 532 Figure 4. A, B Maximum Likelihood tree inferred from concatenated mitochondrial dataset. Values at the internal branches are Ultra-Fast Bootstrap (UFB) support. Outgroups are not shown in this figure. Coloured bars on the right are lineages delimited by ASAP and mPTP methods. Scale bar: substitution per site. Values above ASAP bars are the ranks given by ASAP analysis. Vertebrate Zoology 75, 2025, 517–625 533 Figure 4 (continued). Boruah B et al.: Revision of bush frogs from northeast India 534 dalii, R. barakensis sp. nov., R. boulengeri sp. nov., R. mindat, R. hekouensis, R. hillisi, huanglianshan, lawngtlaiensis sp. nov., R. mawsynramensis sp. nov. and R. malipoensis are smaller in body-size compared to the other species (Fig. 5). Whereas R. magnus sp. nov., R. garo and R. arunachalensis sp. nov. are relatively larger (Fig. 5). Although R. garo and R. cangyuanensis are genetically similar with very low divergences (0.0–0.8% in the 16S gene) (Figs 2, 3) the population from northeast India is larger in body size than the ones from China (Fig. 5). This could be a result of geographic separation and regional variation between these two populations. Therefore, body size alone cannot be a reliable character to distinguish some of the widely distributed species in this complex. Multivariate analyses Principal Component Analysis (PCA) computed for all 38 morphometric characters of males revealed the spread of morphological variation in the described and putative species (genetic lineages) from northeast India. Ninty five percent of the variation in the PCA was explained by 15 PCA axes. PCA axes one (PC1) and two (PC2) explained most of the variation (73.9%) in the dataset (Table S8). On the first PC axis (PC1), finger lengths (FLI, FLII and FLIV) and fifth toe length had higher factor loadings (Table S9). The variation in PC axis (PC2) two was less variable compared to PC1 for the 18 putative lineages included in this analysis (Fig. 6). In the R. garo group, the ordination plot showed clear morphological separation between R. garo and other three lineages with no overlap (Fig. 6A). The other three lineages in this group have partial overlap among them (Fig. 6A). Among the putative lineages of R. rezakhani group we studied, all the members have partial overlap in morphospace. Raorchestes mawsynramensis sp. nov. is different among the four species and has minor overlap with R. barakensis sp. nov. (Fig. 6B). Among the putative lineages of the R. kempiae group, R. shillongensis is distinct from all the other lineages (R. kempiae, R. dibangensis sp. nov. and R. monolithus sp. nov.) of the group while R. kempiae has partial overlap with the other two lineages. In the R. annandalii group, the lineages have no overlap except the overlap between R. arunachalensis sp. nov. and R. magnus sp.nov. (Fig. 6D). Sample size for R. boulengeri sp. nov., R. dibangensis sp. nov., R. khonoma sp. nov., and R. lawngtlaiensis sp. nov. species is low (2–4) therefore these results may vary in future with addition of more samples. In the PCA results for R. garo and R. kempiae, 95% of the variation is explained by PC1 to PC5. Axes one (PC1) Figure 5. Visualisation (violin plot superimposed on a box plot; individual data points are overlaid as dots) of body size differences of the male Raorchestes species described in this study and their congeners from Indo-Burma and Indochina are arranged alphabetically. “Raorchestes cangyuanensis” and “R. kempiae” in Naveen et al. (2024) are synonyms of R. garo. “Raorchestes asakgrensis ” is a synonym of R. kempiae . Raorchestes sp1 is an undescribed species misidentified as R. garo by Naveen et al. (2024). The shape of each violin plot represents the distribution density of the data. Wider sections indicate a higher concentration of observations, while narrower sections reflect fewer data points. Vertebrate Zoology 75, 2025, 517–625 535 and two (PC2) explained most of the variation (78.4%) in the dataset (Table S8B). Despite one of the type specimens (ZSI19187) being a subadult, there is a clear separation between the R. garo and R. kempiae samples (Fig. 6E). Type specimens of both the species are well clustered with their respective topotypes. This further emphasizes the fact that the newly collected materials are correctly allocated to the respective species. Bioacoustics The advertisement calls of the 12 species included in this study are of a single type. Calls can be broadly divided into pulsatile and non-pulsatile calls. Three species (R. barakensis sp. nov., R. dibangensis sp. nov. and R. kempiae) have pulsatile calls while the remaining species have non-pulsatile calls (Table 2). Raorchestes eaglenestensis Figure 6. Principal Component Analysis (PCA) of 176 specimens of Raorchestes using 38 morphometric characters (A–D). A Raorchestes garo group, B Raorchestes rezakhani group, C Raorchestes kempiae group + R. khonoma sp. nov. + R. eaglenestensis sp. nov., D Raorchestes annandalii group + R. mindat + R. arunachalensis sp. nov. + R. magnus sp. nov. Sister species plotted with same symbols but with different colours. E PCA of R. garo and R. kempiae specimens using eight morphometric characters. Boruah B et al.: Revision of bush frogs from northeast India 536 sp. nov. and R. mawsynramensis sp. nov. have the shortest call duration (9–20 ms) and R. barakensis sp. nov. has the longest call duration (91–4464 ms). Among the species with pulsatile calls, R. barakensis sp. nov. has 2–59 pulses/call while R. dibangensis sp. nov. and R. kempiae has 2–4 pulses/calls. Raorchestes mawsynramensis sp. nov. and R. orientalis sp. nov. have the highest dominant frequency calls while R. arunachalensis sp. nov., R. garo and R. eaglenestensis sp. nov. have the lowest dominant frequency calls (Table 2). Advertisement calls of the species studied are in support of phylogenetically identified lineages. This makes it a useful tool for field identification of bush frogs in northeast India. Taxonomic conclusions Based on the phylogenetic results with support of morphology, we refer all the collected samples of bush frogs in this study to the genus Raorchestes except for “R. sahai” which we transferred to the genus Nasutixalus and synonymise this species with N. jerdonii (see following section). Additionally, based on our taxonomic approach we describe thirteen new species of Raorchestes from northeast India. In the following section, we first discuss previously described species with ambiguous identity, followed by new species descriptions. Nasutixalus jerdonii (Günther, 1876) Figures 7, 8; Tables S10, S11 Synonymy and chresonymy. Polypedates jerdonii Günther, 1876: 571. Rhacophorus jerdonii — Boulenger (1882): 80; Das and Dutta (1998): 67. Rhacophorus (Rhacophorus) jerdonii — Ahl (1931): 114; Dutta (1997): 101. Rhacophorus (Rhacophorus) buergeri jerdonii — Wolf (1936): 172. Philautus (Kirtixalus) jerdonii — Dubois (1987): 73. Philautus (Philautus) jerdonii — Bossuyt and Dubois (2001): 25. Philautus sahai Sarkar & Ray, 2006: 303. Pseudophilautus sahai — Li et al. (2009): 519. Philautus sahai — Ahmed et al. (2009): 16. Raorchestes sahai — Biju et al. (2010): 1120. Frankixalus jerdonii — Biju et al. (2016): 6–13. Nasutixalus jerdonii — Sivongxay et al. (2016): 439–440. Comments on taxonomic status. Raorchestes sahai (Fig. 7) was originally described as Philautus sahai by Sarkar and Ray (2006) based on two specimens collected by S. S. Saha on 29 February 1988 from 10 km north of Gandhigram, Changlang District, Arunachal Pradesh, India. After Biju et al. (2010), Table 2. Comparison of advertisement calls of Raorchestes species of northeast India described in this study and R. rezakhani from Bangladesh. Species Call delivery pattern Temporal structure No. of calls per group Call duration (ms) Call rise time (ms) Call fall time (ms) Intercall interval (ms) Pulses/call Pulse duration Pulse rate (pulses/sec) Dominant frequency (Hz) Reference R. arunachalensis sp. nov. delivered in group non-pulsatile 2–33 15–25 1–2 14–24 125–158 — — — 2411–2842 This study R. barakensis sp. nov. not delivered in group pulsatile — 91–4464 72–2327 19–2137 534–2281 2–59 10–34 11.73–14.08 3445–3832 This study R. boulengeri sp. nov. delivered in group non-pulsatile 2 20–31 1 20–30 173–216 — — — 3703–3789 This study R. dibangensis sp. nov. not delivered in group pulsatile — 58–127 1–50 11–126 48–514 2 or 3 10–15 16.95–22.22 3143–3316 This study R. eaglenestensis sp. nov. delivered in group non-pulsatile 2–4 9–20 1 12–18 224–270 ———2971–3100 This study R. garo delivered in group non-pulsatile 2–13 20–32 1 19–31 144–170 ———2799–2971 This study R. kempiae not delivered in group pulsatile — 67–200 1 64–199 398–1695 2–4 9–37 18.52–21.74 3057–3488 This study R. mawsynramensis sp. nov. not delivered in group non-pulsatile — 13–20 1 12–19 1127–2133 — — — 4263–4608 This study R. monolithus sp. nov. delivered in group non-pulsatile 5–13 12–29 1 11–28 118–285 — — — 3316–3531 This study R. narpuhensis sp. nov. not delivered in group non-pulsatile — 13–25 1 12–24 544–823 — — — 3574–4134 This study R. orientalis sp. nov. delivered in group non-pulsatile 2–6 15–28 1–3 13–27 162–295 — — — 3617–4177 This study R. rezakhani NA pulsatile NA NA NA NA NA 5–11 3–29 10–19 4320–4770 Al-Razi et al. (2020) R. shillongensis delivered in group non-pulsatile 2–59 12–22 1 11–21 215–281 — — — 3660–3746 This study Vertebrate Zoology 75, 2025, 517–625 537 this species was placed under Raorchestes by implication (Frost 2025). Since its description, this species has not been reported from the type locality and no attempt has been made to study the types or compare them with other species in Raorchestes or other genera of small rhacophorids. We examined the type series (ZSIA8500 and ZSIA8501) available at the Zoological Survey of India, Kolkata. Our examination of the types revealed some characteristics that contradict the original description of the species by Sarkar and Ray (2006), such as vomerine teeth present in both types although underdeveloped (vs. vomerine teeth absent in original description) (Fig. 7); snout truncated in dorsal and lateral view, rounded in ventral view (vs. snout rounded in original description); rudimentary webbing present on hand (vs. not mentioned in original description). Thus, presence of vomerine teeth in the type specimens suggest that this species does not belong to the nominal genus Raorchestes. Between the years 2022 and 2023, we collected three rhacophorid specimens from Gandhigram that morphologically correspond to the type specimens of R. sahai based on the following set of characters such as truncated snout, protruding eyes, vomerine teeth present, tympanum distinct, rudimentary webbing present on hand, webbing well developed on foot, disc on fingers and toes, abdomen and thigh granular (Figs 7 and 8). Furthermore, in our phylogenetic analysis (ML) based on the 16S mitochondrial gene, the newly collected samples (of both subadult and adult) formed a clade with Nasutixalus jerdonii (Günther, 1876) from northeast India (Fig. 8A). The uncorrected p distance between the newly collected samples and available sequences of N. jerdonii from India included in this study are 0.0–0.2% in the 16S gene (Table S10). We also examined the type specimens of N. jerdonii at the Natural History Museum, London collection (BMNH1947.2.7.84 and BMNH1947.2.7.85). Our topotypes agreed with the N. jerdonii types based on the following set of morphological characters: 1) snout rounded or almost truncate in dorsal view and nearly vertical in lateral view; 2) tympanum distinct; 3) small webbing present on hand; 4) circum-marginal groove present on finger and toe disc; 5) toe webbing moderate; 6) granular belly and ventral aspect of thigh; 7) dark patch covering posterior part of head on dorsal aspect, continuing to dorsum and posteriorly bifurcate. The following exceptions or variations were observed in the newly collected material and previously published descriptions. Biju et al. (2016) mentioned that vomerine ridges present in two oblique series without teeth. However, the original description mentioned that vomerine teeth are present. Based on our specimens collected from different parts of northeast India (Meghalaya, Mizoram, and Arunachal Pradesh), most of the specimens of N. jerdonii have blunt vomerine teeth on two oblique series. In some other specimens (for example WII-ADA3240) which is genetically similar, vomerine ridge is present without teeth. Additionally, Jiang et al. (2016) mentioned that vomerine teeth are present in N. medogensis Jiang, Wang, Yan & Che, 2016, while Yang and Chan (2018) mentioned vomerine ridge present without teeth in N. yingjiangensis Yang & Chan, 2018. Thus, this character is not consistent within the genus and species. Biju et al. (2016) mentioned that metacarpal tubercles are absent. However, metacarpal tubercles are visible in the types as well as in our newly collected specimens. Based on the morphological similarity of the topotypes to the holotype and paratype and the phylogenetically close position of the topotypes to N. jerdonii, we consider “R. sahai” to be a junior subjective synonym of N. jerdonii. However, none of the available DNA sequences of N. jerdonii by Biju et al. (2016) and Muansanga et al. (2022) are from the type locality in Darjeeling. Those available sequences are from the hill ranges of the southern slope of the Brahmaputra Valley. Therefore, topotypic samples are needed to determine whether N. jerdonii sensu stricto from Darjeeling and the populations from south of Brahmaputra Valley currently referred to as N. jerdonii belong to the same species or represent different species. Sarkar and Ray (2006) placed this species in the genus Philautus probably because of the small body size of the collected material. Although Sarkar and Ray (2006) referred to the type series as adults, we confirmed that the types are subadults based on the newly collected subadult and adult specimens from the type locality at Gandhigram. Additionally, this species was never compared with N. jerdonii in the past probably because both the species were placed in different genera. For taxonomic stability, we provide here an expanded description of N. jerdonii based on the newly collected material from the type locality of “R. sahai”. Materials examined. A subadult female (WIIADA1770) and an adult male (WII-ADA1773) collected by BB, AD and NGP on 16 September 2022 at Gandhigram (27.265139°N, 96.937041°E, elevation 1120 m a.s.l.), Changlang District, Arunachal Pradesh; an adult male (WII-ADA3240) collected from same locality by AD, SD, RNV and JDG on 23 May 2023. Description of newly collected male specimen (WIIADA1773; Fig. 8B–H). Medium sized rhacophorid frog, SVL 41 mm; head slightly wider than long (HW/HL = 0.98); snout rounded in dorsal and semicircular in ventral view, vertical in lateral view; snout length smaller than eye length (SL/EL = 0.9); canthus rostralis indistinct, oblique; loreal concave; nostrils oval, laterally positioned and obliquely oriented; nostril closer to snout tip than eye; snout anteriorly depressed at internarial space; internarial space equal to inter-upper eyelid width and upper eyelid width; eyes protruding, moderate in size, less than half of head length (EL/HL = 0.42); tympanum distinct, round, nearly half of eye length (HTYD/EL = 0.47); tongue posteriorly notched; choanae round; vomerine teeth present between choanae and angular to body axis; a pair of internal vocal sac openings on lower jaw; habitus stout, its length nearly half of snout-vent length (AG/SVL = 0.47). Forelimbs slender; forearm length smaller than hand length (FAL/HAL = 0.71); third finger longest; fingers with rounded disc; disc on third and fourth finger nearly equal to tympanic diameter; circum-marginal groove Boruah B et al.: Revision of bush frogs from northeast India 538 present on disc; subarticular tubercles rounded and distinct; supernumerary tubercles present; palmar tubercles distinct, oval shaped; rudimentary webbing present between fingers; nuptial pad not visible. Hindlimbs comparatively stout; thigh length and tibia length equal, less than half of snout-vent length (TL/ SVL = 0.43); foot length greater than thigh and tibia length (TL/FOL = 0.96); fourth toe longest; toes with rounded discs; toe discs width slightly smaller than that of fingers; circum-marginal groove present on discs; subarticular tubercles distinct and rounded; supernumerary tubercles absent; inner metatarsal tubercle present; outer metatarsal tubercle absent; webbing moderate, reaching first subarticular tubercle on fourth toe. Skin on dorsal aspect of snout and head smooth with numerous enlarged, distinct spinules including on upper eyelids; similar spinules on loreal region, below eyes, and on mandibular region; skin on dorsum smooth with numerous spinules, which decrease in number posteriorly; flank with flat granular tubercles; ventrum of head and chest smooth; abdomen granular; granules on thigh indistinct; flat tubercles below vent; forelimbs, tibia, and tarsus smooth. Figure 7. “Raorchestes sahai” (= Nasutixalus jerdonii). A–C Holotype of “R. sahai” (ZSIA8500). A Dorsal view, B ventral view, C lateral view of head; D–I paratype of “R. sahai” (ZSIA8501). D Dorsal view, E ventral view, F lateral view of head, G ventral view of left hand, H ventral view of left foot; I–J vomerine teeth in paratype and holotype respectively. Scale bar = 10 mm. Vertebrate Zoology 75, 2025, 517–625 539 Figure 8. A ML tree inferred from 16S mitochondrial gene. UFB values below 50 are not shown on tree. Scale bar represents substitution per site. Newly collected specimens of N. jerdonii from type locality of “R. sahai” Gandhigram, Arunachal Pradesh; B–E topotypic collection WII-ADA1773 in preserved condition; F WII-ADA1773 in life; G–H WII-ADA1770 in preserved condition. Scale bar = 10 mm. Boruah B et al.: Revision of bush frogs from northeast India 540 Colouration in life (based on specimen WII-ADA1773; Fig. 8F). Top and lateral sides of head brown; tip of snout with enlarged olive-brown patch to below nostrils and vertical pale yellow line at tip of snout; a similarly coloured spot in front of interorbital space; olive-brown stripe on loreal region below canthus rostralis; a similarly coloured patch below eyes, bordered with pale yellow; dark brown iris with irregular golden patches; olive-brown streak along anterior part of supratympanic fold and a few irregular spots on tympanum; dorsum pale yellowish brown with enlarged olive brown hourglass shaped patch, starting from interorbital space and covering posterior half of upper eyelids, posteriorly bifurcating in middle of dorsum, directing towards groin as gradually diffusing; two pale yellowish brown spots on dark patch, one on back of head and another elongated one on anterior part of back; flank pale brown with some irregular small olive-brown spots; dorsum of forelimb pale yellowish brown; broad olive-brown band on forearm; similar patch on base of hands and dorsal aspect of fingers; hindlimbs pale yellowish brown on top with three broad olive-brown, irregular bands on each thigh and tibia; small patch of similar colour on knees; similar bands on tarsus, base of foot, and on dorsal aspect of toes; ventrum of head, abdomen, and limbs uniform pale cream coloured. Colouration in preservative. Dorsal aspect of head, dorsum, and limbs brown; markings on head, dorsum, and limbs visible as in life; ventrum of head, back and limbs uniform pale brown. Morphological variation. Overall, the newly collected material from the type locality of “R. sahai” similar to the types of N. jerdonii. However, following variations were observed among the individuals. Head slightly wider than length in WII-ADA1773 which is similar to that of holotype of “R. sahai” (ZSIA8500). However, in the paratype (ZSIA8501) and two newly collected specimens (WII-ADA3240 and WII-ADA1770), head length is equal to head width. Snout length is equal to eye length in the type specimens of “R. sahai” (ZSIA8500, ZSIA8501), but slightly shorter in the newly collected specimens. Snout length greater than eye length in the types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). Inter-upper eyelid width greater than upper eyelid width in the types of “R. sahai” (ZSIA8500, ZSIA8501) and types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). Inter-upper eyelid width is equal to the upper eyelid width in WII-ADA1773 and in two specimens (WII-ADA3240 and WII-ADA1770), inter-upper eyelid width is smaller than upper eyelid width. Internarial distance equal to inter-upper eyelid width in the types of “R. sahai” (ZSIA8500, ZSIA8501) and WII-ADA1773. Internarial distance equal to inter-upper eyelid width in the types of “R. sahai” (ZSIA8500, ZSIA8501) and WII-ADA1773 while internarial distance greater than inter-upper eyelid width in WII-ADA3240 and WII-ADA1770. Internarial distance smaller than inter-upper eyelid width in the types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). Tibia length smaller than thigh length in types of “R. sahai” (ZSIA8500, ZSIA8501) and the two topotypes (WII-ADA3240 and WII-ADA1770) but thigh length and tibia length equal in WII-ADA1773. Tibia length greater than thigh length in the types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). A detailed morphometric variation of the newly collected material is provided in Table S11. Dorsal markings on head, dorsum and limbs of the types are barely visible unlike the topotypes. In addition, WII-ADA3240 has a distinct nuptial pad on the first finger; irregular shaped and sized brown patches present on ventrum of head, chest, and forelimbs of WII-ADA1770. Distribution and natural history. Nasutixalus jerdonii is widely reported from northeast India (Biju et al. 2016). It was previously reported from Darjeeling (Günther 1876); Mawphlang Sacred Grove, Wahlynkien (Marai Kaphon), Cherrapunji in Meghalaya; Zaraengtung, Raenghzaeng Village in Manipur; Sechüma village, Zubza, Meriema Village, Seukwehii, Tseminyu Village in Nagaland (Biju et al. 2016); Hmuifang Community Reserve Forest, Murlen National Park in Mizoram (Muansanga et al. 2022). Rahman et al. (2020) reported this species from Ziradum, Myanmar. Zug (2022) reported this species from northern Myanmar (Kachin). During our study, we recorded the species from Gandhigram and near Glaw Lake at Kamlang Tiger Reserve in Arunachal Pradesh, and in Hmuifang, Mizoram. At Gandhigram, subadult individuals were recorded on leaves at a height of ~20 cm above ground near a small stream ~300 cm wide at around 20:00 hrs. Adult individuals were recorded on leaves at a height of ~100 cm above ground at around 22:00 hrs in September 2022. Calling males were observed active among tree ferns at three meters above ground in late May. Nasutixalus microdiscus (Annandale, 1912) nov. comb. Chresonymy. Rhacophorus microdiscus Annandale, 1912: 114. Rhacophorus (Rhacophorus) microdiscus — Ahl (1931): 57, 121. Philautus (Kirtixalus) microdiscus — Dubois (1987): 73. Philautus (Philautus) microdiscus — Bossuyt and Dubois (2001): 40. Philautus microdiscus — Ahmed et al. (2009): 16. Comments on taxonomic status. What is currently known under Philautus microdiscus (Fig. 9) was originally described by Annandale (1912), based on a single specimen (ZSI16924), as Rhacophorus microdiscus from Kobo in the foothills of Abor (now in Assam; Fig. 1A). This species has never been reported since its description. Gorham (1974) synonymized this species with Rhacophorus jerdonii (now Nasutixalus jerdonii) but this was not followed by Dubois (1987) and Bossuyt and Dubois (2001). Gorham (1974) was only followed by Sarkar and Ray (2006). Dubois (1987) placed this species in the genus Philautus under the subgenus Kirtixalus. Later, Bossuyt and Dubois (2001) transferred it to the nominotypical subgenus Philautus. However, Garg et al. (2021) questioned the placement of this species in the genus Philautus. Based on Vertebrate Zoology 75, 2025, 517–625 541 molecular data of bush frogs collected from across northeast India, we argue that there are no species of the genus Philautus (sensu stricto) present in this region. After a review of Annandale’s original description and examination of the holotype (ZSI16924) we provide the following characters for the holotype: small body size (28.7 mm); presence of vomerine teeth; presence of rudimentary webbing on hand; presence of discs on digits. Annandale (1912) mentioned that the disc on the third finger is less than half of the tympanic diameter, but this may be because the specimen was in a dehydrated state as seen on the sketch provided in the original description); granular abdomen and thighs; subtriangular marking on head; concave stripes on dorsum; crossbars on dorsal surface of limbs (Fig. 9); lateral sides of thighs reddish (based on original description). The holotype being a small bodied frog (28.7 mm) with a comparatively short rounded snout and discs on the fingers and toes (as with species in Nasutixalus, Philautus, Pseudophilautus, and Raorchestes), from northeast India (as we argue only with Nasutixalus and Raorchestes) with vomerine teeth (absent in Raorchestes) strongly suggests that “P. microdiscus” belongs to the genus Nasutixalus Jiang et al., 2016. Species of the genus Nasutixalus (e.g., N. medogensis) are known to occur in the Adi (= Abor) Hills of Arunachal Pradesh (Biju et al. 2016; Yang et al. 2018). During our field surveys over the past five years we recorded several populations of Nasutixalus in the upper reaches of the Adi Hills and throughout the State of Arunachal Pradesh. These recorded specimens partially match Annandale’s description by the following set of characters: dorsally rounded and laterally nearly truncate snout shape, distinct canthus rostralis, presence of vomerine teeth, distinct tympanum, presence of dorsal stripes, presence of dark bar on inter-upper eyelid space, crossbars on limbs, granular belly, discs on fingers, webbing on foot. Thus, we formally transfer Philautus microdiscus to Nasutixalus microdiscus nov. comb. but acknowledge that further studies involving collecting specimens from the type locality or near the type locality of N. microdiscus and including Figure 9. Holotype of Nasutixalus microdiscus nov. comb. (ZSI16924). A Dorsal view (photographed in 2012) showing concave dark stripes on dorsum (with black arrow), B dorsal view, C ventral view, D lateral view of head, E ventral view of head showing vomerine teeth indicated with black arrow (taken in 2024), Sketch of the same specimen from Annandale’s (1912) original description of “Rhacophorus microdiscus”. Scale bar = 10 mm. Boruah B et al.: Revision of bush frogs from northeast India 548 based on the newly collected material from the type locality is necessary. Description of lectotype. Small sized Raorchestes, SVL 16 mm (Fig. 14E, F); lower jaw broken anteriorly; both the forelimbs broken at elbow; left hind limb broken at groin and tibiotarsal articulation; right hindlimb broken at knee and toes completely damaged; longitudinal incision on belly. Snout rounded in dorsal and ventral aspect; canthus rostralis indistinct; vomerine ridge or teeth absent; tympanum indistinct; supratympanic fold distinct; finger disc rounded, circummarginal groove present; thigh length slight greater than tibia length (TBL/TL = 0.98); toe disc rounded, with circummarginal groove; skin on dorsal aspect of head, dorsum and limbs smooth; a few indistinct tubercles on upper eyelids and posterior part of head behind upper eyelids; on ventral aspect, gular region and chest smooth; belly and thigh granular; tibia smooth on ventral aspect. Colouration in preservative. Dorsal aspect of head, dorsum and limbs brown, slightly paler towards flank and base of the hindlimb; ventral aspect nearly uniform brown but slightly paler than the dorsal colour. Except slightly dark patch on groin and slightly dark and single broad cross bar on thigh and tibia, other colour pattern such as dark bar on inter-upper eyelids space, stripes on dorsum; bands on forearms, silvery tinge encircling dark patch on groin as mentioned in the original description are not visible now. Raorchestes garo (Boulenger, 1919) Figures 15–17; Tables 1, 2, S6, S7, S12 Synonymy and chresonymy. Ixalus garo Boulenger, 1919: 207. Rhacophorus (Philautus) garo — Ahl (1931): 70. Philautus garo — Bourret (1942): 450–451; Inger (1985): 528; Ahmed et al. (2009): 15. Philautus (Philautus) garo — Bossuyt and Dubois (2001): 41. Philautus namdaphaensis Sarkar and Sanyal, 1985: 287–289. Raorchestes manipurensis Mathew & Sen, 2009: 43, 44, plate XVI. Philautus namdaphaensis — Ahmed et al. (2009): 16, 147. Raorchestes cangyuanensis Wu et al., 2019: 558–561. Raorchestes kempiae — Naveen et al. (2024): 362, 365–367. Raorchestes garo — Naveen et al. (2024): 362. Comments on taxonomic status. Boulenger (1919) described “Ixalus” garo based on a single specimen (Fig. 15 A–D) collected by Stanley Wells Kemp from “above Tura”, Garo Hills. It was subsequently placed in other rhacophorid genera including Rhacophorus Kuhl & van Hasselt, 1822 and Philautus (Ahl 1931; Bourret 1942; Inger 1985; Bossuyt and Dubois 2001). This species has been reported from Assam (Choudhury et al. 2001), Nagaland (Ao et al. 2003) and Shillong in Meghalaya (Mathew and Sen 2009; Kharkongor et al. 2016). However, it has never been reported from its type locality (above Tura in Garo Hills, Meghalaya) since it was first described. Recently, Naveen et al. (2024) reported this species from Daribokgre Community Reserve in the East Garo Hills District of Meghalaya, claiming that their collected specimen is a “topotype” (see discussion below). During our field survey on 27 May 2022, we encountered an individual of the bush frog (Fig. 16A–H) at the type locality Tura Peak (25.50302°N, 90.23853°E, elevation 1030 m a.sl.), Meghalaya. These individuals resemble the characters mentioned in the original description of R. garo by Boulenger (1919) as follows: 1) dark-brown hourglass shaped mark covering head from interorbital space and back, 2) loreal and temporal region dark-brown, 3) darkbrown crossbars on limbs and 4) distinct tympanum, 5) canthus rostralis distinct. Although the original description stated the snout shape is truncated, it is damaged in the holotype (squeezed, see Fig. 15). Our examination of the newly collected material found that the snout shape is rounded or sub-ovoid. Material examined. Holotype: ZSI 19187, subadult (sex could not be determined); collected by S.W. Kemp above Tura, West Garo Hills District, Meghalaya, India. Newly collected material. Topotypes: five adult males (WII-ADA1493–1496, WII-ADA1499) collected by BB, VJ, and AD on 27 May 2022 from Tura Peak Reserved Forest (25.50302°N, 90.23853°E, elevation 1030 m a.s.l.), West Garo Hills District, Meghalaya. Referred materials: one adult male (WII-ADA1479) collected by BB, VJ, and AD on 20 May 2022 from Daribokgre (25.48973°N, 90.32373°E, elevation 1140 m a.s.l.), West Garo Hills District, Meghalaya; two adult males (WII-ADA858, WII-ADA859) collected by BB and AD on 1 August 2021 from near Kiphire Divisional Forest Complex (25.89940°N, 94.76947°E, elevation 1300 m a.s.l.), Kiphire District, Nagaland; one adult male (WII-ADA861) collected by BB and AD on 2 August 2021 from Aramasangram, (25.83128°N, 94.87319°E, elevation 1480 m a.s.l.), Kiphire District, Nagaland; seven adult males (WII-ADA601–WII-ADA605, WIIADA607, WII-ADA608) collected by BB on 18 April 2019 from Lakhicherra (24.97502°N, 92.77305°E, elevation 50 m a.sl.), Cachar District, Assam; two adult males (WII-ADA609, WII-ADA610) collected by BB on 20 April 2019 from Subhang (24.97613°N, 92.79206°E, elevation 170 m a.s.l.), Cachar District, Assam; two adult males (WII-ADA1035 and WII-ADA1036) collected by BB, NGP, and AD on 9 September 2021 from Ngengpui Wildlife Sanctuary (22.48696°N, 92.77307°E, elevation 180 m a.s.l.), Lawngtlai District, Mizoram; one adult female (WII-ADA1142) collected by BB, NGP, and AD on 16 September 2021 from Teirei (23.694°N, 92.45147°E, elevation 270 m a.s.l.), Dampa Tiger Reserve, Mamit District, Mizoram; one adult male (WII-ADA1645) collected by BB on 25 July 2022 from Leimatak (24.59375°N, 93.66256°E, elevation 480 m a.sl.), Churachandpur District, Manipur; two adult males (WII-ADA1648 and WII-ADA1649) collected by BB on 26 July 2022 from Charoikhullen (24.6071°N, 93.71986°E, elevation 1180 Vertebrate Zoology 75, 2025, 517–625 549 Figure 15. Raorchestes garo. A–D Holotype of Raorchestes garo (ZSI19187), A dorsal view, B ventral view, C, D lateral view of head; E–N “Philautus namdaphaensis”, E–G holotype (ZSIA 7177); H–J paratype (ZSIA 7179); K–N paratype (ZSIA 7178), N granular belly skin. Scale bar = 10 mm. Boruah B et al.: Revision of bush frogs from northeast India 550 m a.s.l.), Churachandpur District, Manipur; four adult males (WII-ADA3211, WII-ADA3213, WII-ADA3217, and WII-ADA3219) collected by RNV and SD on 9 May 2023 from Haldibari (27.52453°N, 96.39913°E, elevation 500 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh. Diagnosis. Small to medium sized Raorchestes, SVL 19.9–26.9 mm in adult males; head length equal to its width or slightly wider than long (HL/HW = 0.9–1.01); snout shape rounded to sub-ovoid in dorsal view, snout length slightly less than or equal to eye length (SL/EL = 0.81–1.03); snout length greater than or equal to inter-upper eyelid width (0.96–1.28); nostrils closer to snout tip than eye or equidistant between the two; internarial distance smaller than inter-upper eyelid width (IN/IUE = 0.71–0.94) and greater or equal to upper eyelid width (UE/IN = 0.73–1.0), inter-upper eyelid width smaller than eye length (0.74–0.94); spinules or tubercles on dorsum; brown patches on groin and thigh; three dark bands on thigh and tibia. Redescription of holotype (ZSIC 19187; Fig. 15A–D). Specimen completely dehydrated; snout squeezed; lower jaw broken at right side; fourth finger disc on left side damaged; right hind limb is dislodged from body; a puncture on anterior part of abdomen. Small sized frog (SVL = 12.3 mm); head length equal to width; eyes moderate, less than half of head length (EL/HL = 0.38); interorbital space equal to eye length and greater than upper eyelid width (UEW/IUE = 0.43); tympanum distinct, round; tongue posteriorly notched; supratympanic fold visible; forelimbs slender, forearm length smaller than hand length (FAL/HAL = 0.81); each finger with rounded discs; circum-marginal groove present on discs; subarticular tubercles distinct, rounded; palmar tubercles indistinct; hindlimbs slender, thigh length more than half of snout-vent length (TL/SVL = 0.57) and slightly longer than tibia (TBL/TL = 0.97); each toes with rounded disc; discs with circum-marginal groove, as wide as those on fingers; subarticular tubercles distinct, rounded; inner metatarsal tubercle present and outer metatarsal tubercle absent; dorsal aspect of head and dorsum smooth; dorsal surface of limbs smooth; flank smooth; throat, chest and ventral side of limbs smooth; abdomen granular. Colouration of holotype (ZSIC 19187) in preservative. Head dorsally brown and paler laterally; dorsum brown and paler towards the flank; enlarged, slightly darker hourglass shaped mark visible on dorsum starting at interorbital space, posterior ends much darker near groin; limbs brown dorsally; pale brown ventrally; brown specks on throat, chest, and anterior part of abdomen and lower arms. Expanded description based on the newly collected topotype (WII-ADA1495: Fig. 16A–H). A medium sized Raorchestes, SVL 25.3 mm; head wider than long (HL/ HW = 0.93); snout rounded in dorsal view, slightly protruding beyond lower jaw in ventral view; snout length slightly smaller than eye length (SL/EL = 0.92) and equal to inter-upper eyelid width; a slight depression on internarial space; nostrils oval, obliqued, closer to snout tip than eyes (NS/EN = 0.88); narial region protruding; canthus rostralis distinct, obliqued; loreal region concave; eyes protruding, moderate in size (EL/HL = 0.38), greater than inter-upper eyelid width (IUE/EL = 0.89); internarial distance equals to upper eyelid width; tympanum round, distinct, nearly one fourth of eye length; supratympanic fold distinct; vomerine teeth absent; choanae round; trunk less than half snout-vent length (TRL/SVL = 0.48). Forelimbs slender; forearm shorter than hand length (FAL/HAL = 0.86); third finger longest; fingers with rounded discs; circum-marginal groove present on discs; disc on finger II, III and IV greater than tympanic diameter; palmar tubercles indistinct; subarticular tubercles distinct, round; proximal subarticular tubercle on finger III and IV smaller than distal subarticular tubercles; fine granular nuptial pad on first finger; webbing absent. Hindlimbs slender; thigh length half of snout-vent length (TL/SVL = 0.52) and slightly greater than tibia length (TBL/TL = 0.98); fourth toe longest; circum-marginal groove present on toe discs; subarticular tubercles distinct, rounded; proximal subarticular tubercle on fourth toe indistinct and small; supernumerary tubercles absent; toe disc width equal to that of fingers; inner metatarsal tubercle present, its length equal to disc width of second toe; outer metatarsal tubercle absent; webbing small, reaching second subarticular tubercle on fourth toe. Skin on dorsal aspect of snout and head smooth with indistinct tubercles on upper eyelids; side of head smooth, with few tubercles behind angle of jaw; spinules starting behind upper eyelids and above supratympanic folds runs along dorsolateral side of trunk and scatter on middle of trunk, posterior part of dorsum smooth; flank granular; forelimbs and hindlimbs smooth dorsally; head on ventral side smooth; chest, lower arms, abdomen and thighs granular; tibia smooth. Colouration in life. Dorsal aspect of head yellowish brown from snout to anterior one third of upper eyelids with irregular brown spots; dorsum yellowish brown with dark brown spots; an hourglass shaped brown mark starting from interorbital space covering posterior two third of upper eyelids to anterior to vent, posteriorly diffused; dark brown spots along the edges of hourglass shaped mark; loreal region and area anterior to nasals brown, area below eyes, lips, tympanic region and mandibular region pale brown with slightly dark brown specks and spots; indistinct brown streak below supratympanic fold starting from posterior corner of eyes to rear of mandible; lower arm of forelimbs yellowish brown dorsally and forearm greyish brown dorsally; a brown crossbar on forearms; hands greyish brown with brown specks; disc of the first and second fingers pale yellow; thighs and tibia yellowish brown dorsally; greyish brown with faint reddish tinge towards outer lateral side of tibia and tarsus; indistinct crossbars on tibia; crossbars on thighs in the form of interconnected spots; large dark brown patch on outer lateral side of thighs and inner lateral side of tibia; Vertebrate Zoology 75, 2025, 517–625 551 irregular shaped dark brown enlarged spots on groin and a slightly paler elongated patch ventral to it; faint brown patch on inner lateral side of thighs; a few dark brown spots above vent; throat, chest, abdomen, ventral aspect of forelimbs, and base of thighs flesh coloured; brown mottling and creamy-white spots on anterior part of lowFigure 16. Raorchestes garo. A–H WII-ADA1495 from the type locality, Tura Peak. A Dorsal view (hourglass shaped dark patch on dorsum is shown with a black arrow), B ventral view, C lateral view of head in preserved condition, D dorsal view, E dorsolateral view, F ventral view, G groin, H thighs. I–M WII-ADA608 from Lakhicherra, Assam. I Dorsal view in preserved condition (Inset image showing spinules on dorsum), J dorsolateral view, K ventral view, L groin, M. thigh; N–Q WII-ADA1499 from the type locality, N dorsolateral view, O dorsal view, P groin, Q thigh. R–T WII-ADA1142 from Terei, Mizoram. R Dorsolateral view, S groin, T thigh; U WII-ADA3217 from Haldibari, Arunachal Pradesh; V, W WII-ADA607 and WII-ADA603 respectively from Lakhicherra, Assam; X. WII-ADA1035 from Ngengpui, Mizoram. Scale bar = 10 mm. Boruah B et al.: Revision of bush frogs from northeast India 552 er jaw and irregularly shaped small brown patches along its edge; gular region slightly pale yellow; brown specks on anterior part of abdomen, ventral aspect of forelimbs, and palm, heavily speckled on forearms; ventral aspect of foot, tibia, and to distal end of thighs heavily speckled with brown. Colouration in preservative. Dorsal markings on head, dorsum and flank same as when alive; dorsum of snout pale cream coloured up to interorbital space including anterior part of upper eyelids, a brown patch in the middle; side of head dark brown; dorsum towards flank palecream coloured with dark brown spots; the dark brown hourglass shaped mark covering head, and dorsum visible as in life; lower arms cream coloured and forearms dark brown; thighs and tibia cream coloured; outer dorsolateral side of tibia dark brown; tarsus and foot dark brown; distinct dark brown crossbars on thigh and tibia; dark brown marbling on ventral side more distinct than in life, dense marbling on chin, along lower jaw, forearms, chest, tibia, tarsus and foot. Sexual dimorphism and morphological variation. Adult males have external vocal sac, internal vocal slits on lower jaw, and nuptial pad on first finger. Details of variation in morphometric characters among individuals are given in Table S12. In addition, marking patterns on head, dorsum, groin and thigh vary among individuals of the species (Figs 16, 17). Dorsal colour varies as pale yellowish brown, pale reddish brown and greyish brown. Hourglass shaped marking dark grey or dark brown (WIIADA1495). This marking is broken in some individuals (WII-ADA607; Figs 16V, 17B) or may be replaced by a pair of broad concave stripes (WII-ADA1035), or completely absent (WII-ADA603; Figs 16W, 17F). Some individuals have a white bar on forehead covering the anterior part of the upper eyelids (WII-ADA608; Figs 16I, J, 17A); groin and thighs may have irregular dark-brown patches or dark-brown patch with bright irregular sized and shaped yellow spots; pale yellow mid-dorsal line may be present and a similar line on hindlimbs originating from the mid-dorsal line above vent and running dorsally along thighs and tibia and ventro-laterally on tarsus (WII-ADA1499; Fig. 16N, O, U); dark brown spots may be present or absent on flank and limbs; one individual from Ngengpui Wildlife Sanctuary have patches of yellow flecks on head, back, hind limbs and lower arms were pale-yellow on top (WII-ADA1035; Figs 16X, 17G); intensity on the spinules and tubercles on head, back and limbs varies among individuals as dense to scattered. Morphological comparison. Raorchestes garo differs from R. annandalii, R. dulongensis, R. hekouensis, R. hillisi, R. huanglianshan, R. jadoh, R. leiktho, R. malipoensis, R. mindat and R. parvulus by larger body size, SVL 19.9–26.9 mm in adult males (vs. SVL in adult males, 17.3–19.6 mm in R. annandalii, 15.0–19.0 mm in R. dulongensis, 16.1–17.5 mm in R. hekouensis, 15.9–17.7 mm in R. hillisi, 17.0–19.6 mm in R. huanglianshan, 13.6–14.0 mm in R. jadoh, 15.7–15.8 mm in R. leiktho,14.6–17.7 mm in R. malipoensis, 16.7–18.3 mm in R. mindat, 17.0–18.6 mm in R. parvulus); it differs from R. annandalii, R. cinerascens nov. comb., R. parvulus, and R. shillongensis by the absence of concave stripes on dorsum (vs. present); it differs from R. andersoni by the presence of spinules on dorsum (vs. scattered tubercles on dorsum) and three dark bands on thigh and tibia (vs. single band on thigh and tibia); it differs from R. kempiae by distinct canthus rostralis (vs. indistinct canthus rostralis), enlarged dark brown patches with or without light patches present on groin and lateral aspect of thigh (vs. a small brown streak present on groin and no dark patches on lateral aspect of thigh), a white bar on inter-upper eyelid space may be present or absent (vs. a distinct or indistinct dark bar may be present or absent), hourglass pattern may be present covering head and dorsum or absent (vs. hourglass pattern absent, only “)(“ mark may be present on dorsum); it differs from R. hillisi, R. huanglianshan and R. menglaensis by its snout length being smaller than or equal to eye length (vs. snout length longer than eye length); differs from R. jakoid by presence of enlarged dark brown patches with or without light patches on groin and lateral aspect of thigh (vs. absent); it differs from R. longchuanensis by inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. menglaensis by its snout length being smaller than or equal to eye length (vs. snout length longer than eye length); it from R. rezakhani by presence of spinules on dorsum (vs. scattered tubercles on dorsum), concave stripes on dorsum absent (vs. present), enlarged brown patches without or with yellow spots on groin present (vs. short brown streak on groin); it differs from R. tytthus nov. comb. by its snout length being smaller than or equal to eye length (vs. snout length greater than eye length), inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length), inter-upper eyelid width smaller than or equal to snout length (vs. inter-upper eyelid width greater than snout length); it differs from R. yadongensis by snout length being greater than or equal to inter-upper eyelid width (vs. inter-upper eyelid width greater than eye length), inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length). Detailed morphological comparison with other congeners included in this study is given in Table 1. Acoustics. The calls of R. garo were recorded at Tura Peak, Meghalaya on 27 May 2022 at an ambient temperature of 28.2°C and at Lakhicherra, Assam on 18 April 2019 at an ambient temperature of 28.8°C between 18:30 hrs and 19:30 hrs. The call description is based on 42 calls from two individuals (WII-ADA1495 and WIIADA601). The calls are single type, non-pulsatile (Fig. 18), initially emitted as a single call without a group, and gradually emitted in groups (4.72 ± 2.22 calls per call group; 2–13 calls/call group). The mean call duration is 28.57 ± 2.74 ms (20–32 ms) with a call rise time of 1 ms and call fall time of 27.55 ± 2.71 ms (19–31 ms). The Vertebrate Zoology 75, 2025, 517–625 553 interval between calls is 154.31 ± 7.02 ms (144–170 ms) when emitted in groups. The mean dominant frequency of the call is 2860.84 ± 49.55 Hz (2799.3–2971.6 Hz). A detailed comparison of the advertisement calls with those of other congeners is presented in Table 2. Figure 17. Different morphs of Raorchestes garo in their natural habitat. A–F Barail hills, Assam; G Ngengpui Wildlife Sanctuary, Mizoram; H Leimatak, Manipur (topotype of R. “manipurensis” WII-ADA1645). Boruah B et al.: Revision of bush frogs from northeast India 554 Phylogenetic relationship and genetic divergence. Raorchestes garo is sister to R. leiktho (UFB 99 and PP 1; Figs 2, 3). The genetic divergence of R. garo with other congeners included in this study are 4.2–9.2% in the 16S, 13.7–21.2% in the cyt b and 9.5–16.4% in the COI gene (Table S7A–C). Distribution and natural history. This species is distributed in northeast India from western part of Meghalaya to the eastern part of Arunachal Pradesh in the Namdapha Tiger Reserve. This species is also distributed in the Barail Hills of Assam and Nagaland, in Manipur, and in Mizoram. It is mostly associated with lowland evergreen forests (Fig. 19A). This species was so far known from 50–1480 m a.s.l. across hills on the southern slopes of Brahmaputra Valley, India. Al-Razi et al. (2020a) reported this species as R. longchuanensis from Satchari National Park in Bangladesh. Wu et al. (2019) reported this species as R. cangyuanensis from Cangyuan, China. Lalronunga et al. (2021) reported from Mizoram as R. cangyuanensis. Choudhury et al. (2001) reported this species from Garbhanga Reserve Forest and Kulsi Reserve Forest in Assam, and Ao et al. (2003) reported it from Dzulake, Nagaland which needs further examination to confirm the records. Calling males were recorded during April–June from perches 1–2 metres above the ground and from roadside forest areas dominated by bamboo thickets (Fig. 20A, B). We also recorded the species calling from the leaves of a small tree about five metres above the ground and from a bamboo thicket at a height of six metres above the ground in Charoikhullen, Manipur. We observed a single female individual of this species on roadside vegetation in Teirei, Dampa Tiger Reserve, Mizoram in September 2021. Remarks. Naveen et al. (2024) reported rediscovery of “R. garo” based on five specimens (SACON VA 809, 163, 305, 306, 308) collected from an unnamed locality with geographical coordinate given as “25.51°N, 90.38°E, 895 m” in Garo Hills, Meghalaya and one specimen (SACON VA 129) from Daribokgre Community Reserve (25.47297°N, 90.3148°E, 1200 m), that they claimed as a “topotype”. However, the 16S gene sequence data in Naveen et al. (2024) comes from a specimen (SACON VA 809) collected approximately 15 km east of Tura. Morphological description of the alleged “topotype” (SACON VA 809) do not match the original description in terms of dorsal colour pattern. The original description of R. garo mentions an hourglass pattern on dorsum, but this was absent in SACON VA 809. Although Naveen et al. (2024) mentioned that two of the specimens such as VA 305 and VA 308 have hourglass patterns, they did not generate molecular data for these two specimens. The holotype (ZSIC19187) of R. garo was originally collected by S.W. Kemp from “above Tura” which is the ridge/peak immediately above Tura (see Paiva 1919). We therefore argue that without justification, Naveen et al. (2024) considered SACON VA 809 as a topotype of R. garo, and provided a misleading phylogenetic status of R. garo. The DNA sequence (16S) of the “R. garo” topotypical specimen (SACON VA 809) submitted by Naveen et al. (2024) did not cluster with our topotypical samples of R. garo (WII-ADA1493, WII-ADA1494, WII-ADA1499) collected from Tura Peak (= above Tura) (25.50302°N; 90.23853°E; elevation 1030 m a.s.l.; Figs 2, 3). The genetic divergence of the true topotypical samples of R. garo and the specimen of “R. garo” of Naveen et al. (2024) is 6.5–7.0% in 16S gene (Table S7A–C). Naveen Figure 18. Advertisement calls of R. garo (WII-ADA1495) on left and R. kempiae (WII-ADA1497) on right. From top to bottom, A, B oscillograms, C spectrogram, D power spectrum. The call marked with an arrow on top in A is expanded in B. Vertebrate Zoology 75, 2025, 517–625 555 et al. (2024) stated that R. garo is phylogenetically allied to R. shillongensis. However, our phylogenetic analyses indicate R. shillongensis (topotype; WII-ADA1460) as distinct from R. garo (topotype; WII-ADA1493, WIIADA1494, WII-ADA1499; Figs 2, 3). Our phylogenetic analyses are strongly supported by acoustic characterisFigure 19. Distribution of Raorchestes species in northeast India. A Raorchestes garo and three others closely related new species; B Raorchestes kempiae, R. shillongensis, R. mindat and three new species. Type localities are denoted with stars. Boruah B et al.: Revision of bush frogs from northeast India 556 Figure 20. Habitat at the type localities of Raorchestes species of northeast India. A Forest trail at Tura Peak, the type locality of R. garo and R. kempiae; B forest cover and adjacent lowlands of Garo Hills, from Daribokgre; C a landscape view of forest covers and D a forest trail at Namdapha TR, type localities of R. orientalis sp. nov. and R. nasuta sp. nov.; E hills at Mawsynram, near the type locality of R. mawsynramensis sp. nov.; F Nohkalikai Waterfall and forest cover at the type locality of R. boulengeri sp. nov. in Cherrapunji; G dry stream bed and vegetation in Maruwacherra, near Barail WLS, the type locality of R. barakensis sp. nov. and H forest around Jaintia Hills in Narpuh WLS, at the type locality of R. narpuhensis sp. nov. Vertebrate Zoology 75, 2025, 517–625 557 tics of the two species (see under respective description and comparison). This suggests that SACON VA 809 reported by Naveen et al. (2024) is a misidentification of R. garo and it represents an undescribed lineage of Raorchestes. Thus, we consider SACON VA 809 as an invalid topotype of R. garo based on accurate type locality and the phylogenetic results of this study. “Philautus namdaphaensis” was originally described by Sarkar and Sanyal (1985) from Farmbase Camp (at 350 m a.s.l.), Namdapha National Park, Arunachal Pradesh based on three adult males collected by S. Biswas. Later, Sengupta et al. (2000) reported this species from Garbhanga Reserve Forest, Assam, and Mathew and Sen (2009), and Sen et al. (2013) reported it from Nokrek Biosphere Reserve, Meghalaya. On 9 May 2023 we collected two specimens of bush frogs from Haldibari (27.52453°N; 96.39913°E; elevation 500 m a.s.l.), Namdapha Tiger Reserve, Arunachal Pradesh (Fig. 15U) on the north bank of the Noa-Dihing River. These two specimens conform to the original description of “Philautus namdaphaensis” based on the following characters: 1) mid dorsal line from snout to vent, 2) limbs with crossbars and a line originating at vent reaching to heel through dorsal aspect of thigh and tibia, 3) white bar on interorbital space, 4) dark brown blotches on groin and lateral aspects of thighs. “Raorchestes manipurensis” was described by Mathew and Sen (2009) from Leimatak, Manipur based on a single specimen. So far, this species is only known from the type locality. On 25 July 2022 we collected a topotypical specimen (WII-ADA1645; Fig. 17H) from Leimatak (24.59375°N; 93.66256°E; elevation 480 m a.sl.) that conforms to the original description. This individual matches the original description by the following set of characters: 1) head wider than length, 2) distinct canthus rostralis, 3) vomerine teeth absent, 4) a faint hourglass shaped patch covering head from inter-upper eyelid space and back (dark in holotype), posterior ends of this patch directing towards groin; 5) brown and pale white patches on flank near groin. Our phylogenetic analyses involving topotypical samples of “P. namdaphaensis” and “R. manipurensis” resulted with them nested with the topotypical samples of R. garo (Figs 2, 3). The topotypical samples of R. garo have genetic divergences of 0.0–0.6% with topotypical samples of “P. namdaphaensis” and 0.4–1.1% with the topotypical sample of “R. manipurensis” in the 16S gene (Table S7A–C). Morphological examinations of the topotypes of the three species (R. garo, “P. namdaphaensis” and “R. manipurensis”) and examinations of the type series of “P. namdaphaensis” did not reveal any strong differentiating characters to separate these three species. Morphological and molecular studies of the newly collected material from different localities in northeast India suggests R. garo is a polymorphic species (see under redescription section above). We have recorded individuals of R. garo from Tura peak that resemble the typical morphotype of “P. namdaphaensis” (Fig. 16A–H). Mathew and Sen (2008) also reported “P. namdaphaensis” from Nokrek Biosphere Reserve, Meghalaya probably based on this character. The colour and pattern of “R. manipurensis” provided in the original description and the photograph of the holotype by Mathew and Sen (2009) resemble the typical morphotype of R. garo from the type locality. Therefore, these are unreliable and cannot be used as diagnostic characters. Based on molecular data and morphological characters, we propose to treat “Philautus namdaphaensis” and “R. manipurensis” as junior subjective synonyms of R. garo. “Raorchestes cangyuanensis” was described from Cangyuan, China (Wu et al. 2019). Subsequently, Lalronunga et al. (2021) reported this species from Hmuifang, Mizoram and referred to a previous record of R. longchuanensis from Satchari National Park, Bangladesh (AlRazi et al. 2020a) as “R. cangyuanensis”. Rahman et al. (2022) reported the species from northeast Bangladesh. Based on the results of their phylogenetic study, Naveen et al. (2024) suggested “R. cangyuanensis” as a junior subjective synonym of R. kempiae. However, in our current phylogenetic analyses, “R. cangyuanensis” is nested with the topotypical samples of R. garo (Fig. 3) collected in this study (see comments under R. kempiae). The genetic divergence between R. garo collected for this study and “R. cangyuanensis” samples is 0.0–0.9% in the 16S gene (Table S7A–C). Thus, we consider “R. cangyuanensis” as a junior subjective synonym of R. garo and state that the previous records of “R. cangyuanensis” from Mizoram should be considered as R. garo. Raorchestes kempiae (Boulenger, 1919) Figures 21, 22; Tables 1, 2, S6, S12 Synonymy and chresonymy. Ixalus kempiae Boulenger, 1919: 208. Rhacophorus (Philautus) kempiae — Ahl (1931): 53, 69. Philautus kempiae — Bourret (1942): 450–451; Inger (1985): 91; Ahmed et al. 2009: 16. Philautus (Philautus) kempiae — Bossuyt and Dubois (2001): 41. Raorchestes asakgrensis Naveen et al., 2024: 362, 365–370. Raorchestes kempiae — Naveen et al. (2024): 365–367. Comments on taxonomic status. Boulenger (1919) described Raorchestes kempiae based on a single specimen collected by A. Kemp from “above Tura”, Garo Hills. The type locality refers to the ridge/peak immediately above Tura (see Paiva 1919). It is possible that this specimen was collected in 1917, which is evident from Paiva (1919) and Brunetti (1918) that A. Kemp was part of their expedition. However, there was no allocated voucher number available for the type in the original description. Chanda (1994) mentioned a possible location of the type specimen as the “British Museum, (Natural History), London, U. K.” which was followed by Bossuyt and Dubois (2001) and repeated in Frost (2025). Chanda et al. (2000) did not provide the presence of the type specimen of “Ixalus kempiae” or “Philautus kempiae” in the collection of the National Zoological Collection of Zoological Survey of India (ZSI), Kolkata (Calcutta). Boruah B et al.: Revision of bush frogs from northeast India 564 Sexual dimorphism and morphological variation. Males have a pair of internal vocal sac openings, subgular external vocal sac and nuptial pad on the first finger; head longer than wide in females, but in males head wider than long or width equal to length. Dorsal colour varies from pale greyish brown to pale yellowish brown; concave stripes on dorsum may be broken or faint in some individuals; number of crossbars on thigh and tibia varFigure 23. Raorchestes orientalis sp. nov. A Dorsal view, B ventral view of holotype (WII-ADA1309) in preserved condition; C dorsal view of WII-ADA1389 in preserved condition; D dorsolateral view and E ventral view of holotype in life (inset image showing granular skin of abdomen); F WII-ADA3423 in life; G-J WII-ADA1387 in life, G dorsolateral view (inset image showing enlarged bluntly conical tubercles on upper eyelids), H ventral view, I groin, J posterior view of thighs; K an uncollected calling male from Kamala Valley, Namdapha TR; L WII-ADA1631 in life. Scale bar = 10 mm. Vertebrate Zoology 75, 2025, 517–625 565 ies between 2–4; axilla and groin may be pale yellow in some individuals; disc on inner two fingers may be pale yellow. Detailed morphometric variation between the individuals of this species is given in Table S12. Morphological comparison. Raorchestes orientalis sp. nov. differs from R. andersoni by short stripe present on groin (vs. large black spot with two yellow spots present on groin); it differs from R. annandalii by skin on dorsum with spinules (vs. skin on dorsum smooth); it differs from R. cinerascens nov. comb. by short stripe present on groin (vs. a spot partially encircled by yellow tinge present on groin), dense spinules on dorsum (vs. scattered tubercles on dorsum); it differs from R. dulongensis by presence of nuptial pad on first finger in males (vs. nuptial pad absent); it differs from R. hekouensis by nuptial pad present only on first finger (vs. nuptial pad present on first and second finger); it differs from R. garo by short stripe present on groin (vs. enlarged dark brown patches with or without white or yellow patches present on groin); it differs from R. hillisi, R. huanglianshan, R. menglaensis, and R. tytthus nov. comb. by snout length being less than Figure 24. Comparative spectrograms and oscillograms illustrating representative calls of four species of Raorchestes described in this study. A, B Oscillograms, C spectrogram, D power spectrum. The call marked with an arrow on top in A is expanded in B. Boruah B et al.: Revision of bush frogs from northeast India 566 or equal to eye length (vs. snout longer than eye length); it differs from R. jadoh and R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length), and thigh length being greater than or equal to tibia length (vs. thigh length less than tibia length); it differs from R. kempiae by presence of disFigure 25. Distribution of Raorchestes species in northeast India. A Raorchestes rezakhani and four other closely related species; B Raorchestes annandalii and three new species. Type localities are denoted by stars, and other localities are denoted by circles. Vertebrate Zoology 75, 2025, 517–625 567 tinct “)-(“ on dorsum (vs. comparatively faint “)(“mark on dorsum), 2–4 cross bars on tibia and thigh (vs. three bars on tibia and thigh); it differs from R. leiktho by presence of a pair of concave stripes on dorsum (vs. pair of anteriorly connected stripes on dorsum); it differs from R. longchuanensis by inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by short stripe present on groin (vs. black patches present on groin); it differs from R. mindat by short stripe present on groin (vs. enlarged black and white patches present on groin); it differs from R. parvulus by short stripe present on the groin (vs. dark brown marbling enclosing a whitish blotch present on groin); it differs from R. rezakhani by presence of dense spinules on dorsum (vs. scattered tubercles on dorsum); it differs from R. shillongensis by short stripe present on groin (vs. dark brown patch with white crown shaped mark present on groin); it differs from R. yadongensis inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length). Morphological comparisons with other new species described in this study are given in respective sections and Table 1. Acoustics. The calls of R. orientalis sp. nov. were recorded in Deban, Namdapha Tiger Reserve on 10 May, 2022 and in Kamala Valley, Namdapha Tiger Reserve on 16 May 2022 at 19:25 hrs and 19:30 hrs at ambient temperatures of 25.8°C and 22.7°C respectively. The description of calls is based on 60 calls including those of the two individuals (WII-ADA1309 and WII-ADA1367). The calls are single type, non-pulsatile, emitted as a single call at start, gradually emitting calls in groups (2–6 calls per group) (Fig. 24). The mean call duration is 24.6 ± 2.79 ms (15–28 ms) with a rise time of 1.13 ± 0.39 ms (1–3 ms) and a fall time of 23.43 ± 2.85 ms (13–27 ms). The mean interval between calls is 220.92 ± 23.13 ms (162–295 ms) when calls emitted in groups. The dominant frequency is 3958.52 ± 202.2 Hz (3617.6–4177.4 Hz). A detailed comparison of the advertisement calls with those of the congeners is presented in Table 2. Phylogenetic relationship and genetic divergence. Raorchestes orientalis sp. nov. is sister to two other new species with strong node support (UFB 100, PP 1) (Figs 2, 3). The genetic divergence with its congeners is 3.2– 9.1% in the 16S, 9.3–18.7% in the cyt b and 6.0–14.9% in the COI genes (Table S7A–C). Etymology. The specific epithet is derived from the word “oriental” meaning eastern, in reference to its distribution in the easternmost part of India. Suggested common name. Eastern bush frog. Distribution and natural history. Raorchestes orientalis sp. nov. is currently known from Namdapha Tiger Reserve, Kamlang Tiger Reserve and Gandhigram Village in Arunachal Pradesh, and Liyai Khunou in Manipur (Fig. 25A). Calling males were recorded among understorey of evergreen forest at approximately one metre height above ground (Fig. 20C, D). In Gandhigram this species was recorded among shrubs near small streams in the forests and near human settlements. Raorchestes mawsynramensis sp. nov. https://zoobank.org/D770C5B1-65BD-4BAC-8BCF-9653DFC6F9C5 Figure 26; Tables 1, 2, S12 Holotype. An adult male (WII-ADA1531) collected by BB on 1 June 2022 near Mawrapat (25.26144°N, 91.53468°E, elevation 1140 m a.s.l.), East Khasi Hills, Meghalaya, India. Paratypes. Six adult males (WII-ADA1533–WIIADA1538), and an adult female (WII-ADA1530). Collection details are the same as for the holotype. Diagnosis. Small sized Raorchestes, SVL 16–18.7 mm in adult male, SVL in adult female at least 20.0 mm; head length equal to slightly less than width (HL/HW = 0.92–1.0); vomerine teeth absent; snout rounded on dorsal view; snout length equal to or slightly less than eye length (SL/EL = 0.87–1.0); nostril equidistant between eye and snout tip; dense spinules on dorsal aspect of head, dorsum and limb, intermixed with scattered bluntly conical tubercles; dorsally pale brown to dark brown; dark brown “)-(“ mark on dorsum; indistinct or distinct dark brown crossbars on forelimb and hindlimb; yellow bar on inter-upper eyelid space may be present; tips of bluntly conical tubercles white; irregular sized white flecks on flank, lateral aspect of head, and on abdomen; supratympanic fold and lower arm pale yellow. Description of the holotype. Holotype in good condition except for an incision on ventral side of right thigh; SVL 17.8 mm, dorsoventrally flattened; head slightly wider than long (HL/HW = 0.92); snout rounded in dorsal view and nearly truncated in lateral view, slightly protruding in ventral view; snout length slightly less than eye length (SL/EL = 0.88); canthus rostralis distinct, rounded and nearly vertical; loreal region concave; tympanum indistinct, rounded, less than one third of eye length (HTYD/ ED = 0.28); supratympanic fold distinct; internarial distance smaller than inter-upper eyelid width (INS/IUE = 0.9) and slightly greater than upper eyelid width (UEW/ IUE = 0.89); nostril oval, obliquely oriented, equidistant between eye and snout tip, narial region slightly protruding, internarial space slightly concave on dorsal aspect; inter-upper eyelid space flat; vomerine teeth absent; choanae round; tongue notched posteriorly; trunk dorsoventrally flattened, less than half of snout-vent length (AG/ SVL = 0.47). Forelimbs slender, forearm shorter than hand length (FAL/HAL = 0.75); digits with rounded disc, circum-marginal groove present on each disc; metacarpal Boruah B et al.: Revision of bush frogs from northeast India 568 tubercles indistinct; disc widths of third and fourth finger greater than tympanic diameter; distinct, large and finely granular nuptial pad present on first finger, covering ventrolateral and dorsolateral aspect; subarticular tubercles round, proximal ones on third and fourth fingers smaller and indistinct than distal ones and indistinct, SAT = 1:1:2:2; webbing among fingers absent; relative length of fingers = I<II<IV<III. Hind limbs slender; thigh length half of snout-vent length (TL/SVL = 0.49), slightly greater than tibia length (TBL/TL = 0.95), and greater than foot length (FOL/ TL = 0.77); heels slightly overlapping when tibia folded perpendicular to body axis; relative length of toes = I<II<II<V<IV; toes with rounded disc, width of toe disc equal to those on finger, fourth toe disc largest, disc on fourth and fifth toes wider than tympanic diameter; circum-marginal groove present on each disc; narrow inner metatarsal tubercle present, outer one absent; subarticular tubercles round, proximal ones on TIII-TV indistinct; supernumerary tubercles absent; webbing among the toes slight, between TI and TII rudimentary, webbing not reaching second subarticular tubercle of fourth toe. Skin on dorsal aspect of snout and head shagreen, spinules not visible as in life condition; indistinct tubercles on inter-upper eyelid space and on upper eyelid; bluntly conical tubercles on head and upper eyelid distinctly visible in life; few distinct tubercles behind angle of jaw; dorsum shagreen with dense spinules, posteriorly spinules not as dense as anterior part; spinules more distinct dorsal to supratympanic fold and dorsum; flank with dense spinules; forelimb and hindlimb smooth in preserved condition, but spinules and blunt tubercles distinctly visible in life; indistinct flat tubercles present around vent; throat and chest smooth; abdomen and ventral aspect of thigh granular; tibia smooth; flat tubercle along outer dorsoventral aspect of tarsus; small granules scattered on dorsal surface of tongue. Colouration in life. Dorsal aspect of head and dorsum dark brown; lateral aspect of head whitish with tiny brown speckle, irregular white patches and tiny dots on upper and lower jaw; tip of tubercles and spinules white; supratympanic fold orange yellow; flank whitish with pale brown tinge and brown speckle; lower arm orange yellow; upper arm pale brown with two indistinct and slightly dark brown crossbars; finger disc with dense brown speckle, orange yellow patch on some of finger discs; thigh dorsally pale brown with slightly dark brown speckle on it, knee slightly darker; lateral aspect of thigh pale brown, towards vent whitish with brown speckle, enlarge dark brown patch around vent; tibia pale brown with indistinct slightly darker crossbar and whitish speckle; tibia and foot pale brown with darker brown and white speckles; toe disc with dense brown speckle; tip of tubercles on hindlimb white; tubercles along tarsus white; throat, abdomen and ventral aspect of limb whitish with brown mottling; small white spots irregularly placed on gular region; white spots of irregular size on abdomen, ventrolateral aspect of flank, upper arm, thigh, and tarsus. Colouration in preservative. Head dorsally pale brown, upper eyelid dark grey; inverted triangular dark grey mark on parietal region; loreal region slightly darker, lateral aspect of head pale yellowish with brown speckle; dorsum greyish brown, paler towards lateral side; a slightly dark brown “)-(“ mark on dorsum of which anterior ends starts from upper eyelid and posterior ends extends to groin; in life condition this marking was not visible; forelimb and hindlimb pale yellowish with brown mottling; indistinct brown crossbars visible on forearm, thigh, and tibia; ventrally uniform pale-yellowish with brown mottling. Sexual dimorphism and morphological variation. Snout-vent length of the collected males (N = 7) smaller than that of the single female. In males, a pair of internal slits present on the lower jaw; an external large subgular vocal sac present in male; enlarged nuptial pad present on the first finger of males. Live colouration varies among individuals, paratype (WII-ADA1531) had an orange-yellow bar on inter-upper eyelid space followed by a pair of short orange yellow stripe which are joint posteriorly; in WII-ADA1530 reddish brown hourglass shaped mark on dark brown present on dorsum. In addition to these variation, intensity of dorsal spinules and tubercles varies among individuals, WII-ADA1530 and WII-ADA1537 has comparatively fewer scattered spinules on dorsum unlike other individuals; marking on dorsum and crossbars on limbs faint in WII-ADA1537 and WII-ADA1538; crossbars on limbs of WII-ADA1536 narrow and more distinct than that of other individuals; dorsal skin on head nearly smooth in WII-ADA1530, WII-ADA1536 and WII-ADA1538; other morphometric variations are given in Table S12. Morphological comparison. Raorchestes mawsynramensis sp. nov. differs from R. andersoni, R. leiktho and R. malipoensis by the position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. annandalii by presence of dense spinules on dorsum (vs. skin on dorsum smooth); it differs from R. garo by smaller body size, SVL 16.0–18.7 mm in adult males (vs. SVL 19.9–26.9 mm in adult males); it differs from R. cinerascens nov. comb. and R. rezakhani by presence of dense spinules on dorsum (vs. scattered tubercles on dorsum); it differs from R. dulongensis by head length being equal to or less than width (vs. head longer than wide), position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. hekouensis by presence of nuptial pad only on first finger (vs. nuptial pad present on first and second fingers); it differs from R. hillisi and R. huanglianshan by snout length less than eye length (vs. snout length snout length greater than eye length), position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. jadoh by larger body size in adult males, SVL 16.0–18.7 mm (vs. SVL 13.6– 14.0 mm); it differs from R. jadoh and R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length), and thigh length being greater than or equal to tibia length (vs. thigh length less Vertebrate Zoology 75, 2025, 517–625 569 Figure 26. Raorchestes mawsynramensis sp. nov. A–C Holotype (WII-ADA1531) in preserved condition, A dorsal view (inset image showing dorsal spinules on dorsum), B ventral view, C lateral view of head. D–G paratype (WII-ADA1530) in preserved condition. D Dorsal view, E ventral view (inset image showing granular abdomen skin), F ventral view of left hand, G ventral view of left foot. H Holotype in life, I paratype (WII-ADA1538) in life; J paratype (WII-ADA1534) in life; K paratype (WII-ADA1530) in life. Scale bar = 10 mm. Boruah B et al.: Revision of bush frogs from northeast India 570 than tibia length); it differs from R. kempiae by presence of dark brown “)-(“ mark on dorsum (vs. concave stripes on dorsum absent or faint); it differs from R. longchuanensis by inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. menglaensis by snout length being smaller than eye length (vs. snout length snout length longer than eye length), head length being equal to or less than width (vs. head longer than wide); it differs from R. mindat by presence of dark patches on groin (vs. enlarged black and white patches present on groin), absence of white patches on lateral aspect of thigh (vs. enlarged white patches on lateral aspect of thigh); it differs from R. parvulus by presence of dense spinules on dorsum (vs. scattered spinules on dorsum); it differs from R. orientalis sp. nov. by presence of comparatively dense spinules on head and dorsum (vs. comparatively less spinules on head and dorsum), distinct enlarged tubercles absent on dorsal aspect of head absent (vs. enlarged bluntly conical tubercles on dorsal aspect of head present), three crossbars on thigh and tibia (vs. two to four crossbars on thigh and tibia); it differs from R. shillongensis presence of spinules on dorsum (vs. small blunt tubercles on dorsum); it differs from R. tytthus nov. comb. by snout length being less than or equal to eye length (vs. snout length greater than eye length); it differs from R. yadongensis by inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length. Morphological comparisons of R. mawsynramensis sp. nov. with our newly described species in this study are provided in respective sections and in Table 1. Acoustics. The calls of R. mawsynramensis sp. nov. were recorded at its type locality on 1 June 2022 between 18:30–19:15 hrs at an ambient temperature of 24.4°C–26.0°C. The call description is based on 40 calls including those from two individuals (WII-ADA1531 and WII-ADA1534). The calls are single type, non-pulsatile, emitted as a single call at regular intervals, not in groups (Fig. 24). The mean call duration is 16.2 ± 1.99 ms (13– 20 ms) with a rise time of 1 ms and a fall time of 15.48 ± 2.09 ms (12–19 ms). The mean interval between calls is 1418.5 ± 264.94 ms (1127–2133 ms). The dominant frequency is 4403.55 ± 74.74 Hz (4263.6–4608.1 Hz). A detailed comparison of the advertisement calls with those of other congeners is presented in Table 2. Phylogenetic relationship and genetic divergence. Raorchestes mawsynramensis sp. nov. is sister to R. boulengeri sp. nov. (UFB 100, PP 1.0; Figs 2, 3) with genetic divergence of 2.5–2.9% in the 16S, 3.9–4.4% in the cyt b and 3.6–3.9% in the COI genes. The genetic divergences with other congeners included in this study are 3.2–9.8% in the 16S, 9.3–18.2% in the cyt b and 3.6–15.6% in the COI genes (Table S7A–C). Etymology. This specific epithet is a toponym derived from the name “Mawsynram” in Meghalaya State which is the wettest place on earth. Suggested common name. Mawsynram bush frog. Distribution and natural history. Raorchestes mawsynramensis sp. nov. is known only from the type locality around Mawrapat, approximately 5 km southwest of Mawsynram, Meghalaya (Fig. 25A). Calling males were found about 1–1.5 m above ground on a slope in the forest; the area was covered by mostly bamboo species and a few palm trees, ferns and shrubs with thick leaf litters; there was a small stream at this site and a road through the forest connecting Mawrapat and Mawsynram (Fig. 20E). We found the single female individual among leaf litter. Other sympatric anuran species found at this locality include Rhacophorus bipunctatus Ahl, 1927, Kurixalus sp. Xenophrys sp. and Amolops sp. Raorchestes boulengeri sp. nov. https://zoobank.org/B794ACB2-00BF-4C16-9434EA761972F390 Figure 27; Tables 1, 2, S12 Holotype. An adult male (WII-ADA1539) collected by BB on 2 June 2022 from Cherrapunji (25.27696°N, 91.69745°E, elevation 1380 m a.s.l.), approximately one kilometre east of Nohkalikai Waterfall, East Khasi Hills, Meghalaya, India. Paratypes. Three adult males (WII-ADA1540, WIIADA1541 and WII-ADA1542). Collection details are the same as for the holotype. Diagnosis. Small sized Raorchestes, adult male, SVL 17.5–19.1 mm; female unknown; head length equal to width; vomerine teeth absent; snout rounded in dorsal view; snout length less than or equal to eye length; snout length greater than inter-upper eyelid width; nostril equidistant between eye and snout tip; bluntly conical tubercles on dorsal aspect of head, upper eyelid, behind eyelid, dorsolateral aspect of trunk, on dorsal aspect of tibia, and tarsus; spinules on dorsum; nuptial pad present on first finger in males; pair of concave dark brown stripes on dorsum; crossbars on forearm, thigh, and tibia; lower arm orange yellowish; supratympanic fold pale yellowish; finger disc yellow; irregular sized white patches on axilla, groin and abdomen. Description of the holotype. Holotype is in good condition except for an incision under right thigh; adult male with vocal sacs, SVL 17.9 mm, overall specimen in good condition, a small portion of muscle from ventral side of right thigh was sampled. Body slender, dorsoventrally flattened, head oval in shape, dorsoventrally flattened, length equal to width; snout rounded in dorsal view, acute in lateral view, slightly protruding beyond lower jaw; vomerine teeth absent; choanae round; tongue posteriorly broad and slightly notched medially at posterior end; pair of slit like openings on lower jaw; snout length Vertebrate Zoology 75, 2025, 517–625 571 slightly less than eye length; canthus rostralis distinct, rounded and vertical; loreal region concave; inter-upper eyelid space flat; narial region slightly raised; internarial distance slightly less than inter-upper eyelid width (INS/ IUE = 0.87) and greater than upper eyelid width (UEW/ INS = 0.75); nostril oval, laterally positioned, obliquely oriented, equally positioned between eye and snout tip; eye moderate in size (EL/HL = 0.45), protruding in life condition; tympanum barely visible, (HTYD/EL = 0.3); supratympanic fold distinct; trunk slender, dorsoventrally flattened, less than half of snout-vent length (AG/SVL = 0.45). Forelimbs slender; forearm slightly longer than hand length; digits with rounded disc, disc on third and fourth finger slightly wider than tympanic diameter; circum-marginal groove on disc present; palmar tubercles barely visible; indistinct flat granules present on palm; subarticular tubercles large distinct and round, proximal ones on finger III and IV smaller than distal subarticular tubercles; subarticular tubercles on finger I–IV = 1:1:2:2; enlarged nuptial pad on first finger; relative length of fingers = I<II<IV<III; webbing among fingers absent. Hindlimbs slender; thigh length nearly equal to tibia length (TBL/TL = 0.97) and half of the snout-vent length (TL/SVL = 0.49); tibia longer than foot length (FOL/TBL = 0.89); toes with rounded disc; relative length of toes = I<II<V<III<IV; circum-marginal groove present on toe disc; disc on fourth toe as wide as disc on finger III and IV; elliptical inner metatarsal tubercle present, outer one absent; subarticular tubercles visible, round (1:1:2:3:2); webbing slight, not reaching second subarticular tubercle on fourth toe. Dorsal skin on head nearly smooth, upper eyelid granular with indistinct blunt tubercles; few tubercles on mandibular region posterior to angle of jaw; tubercles above supratympanic fold and above axilla running dorso-laterally to middle of the trunk; flank granular, becoming distinct ventro-laterally; tubercles and spinules on head and dorsum in preserved condition not distinct as in life; tubercles on forelimb and hindlimb not visible in preserved condition unlike in life; gular skin loose; skin on chest, abdomen, and on ventral aspect of thigh granular, but granules not as distinct on abdomen; ventral side of forelimbs with barely visible flat granules to palm; tibia and tarsus smooth. Colouration in life. Head dorsally brown; anterior part of inter-upper eyelid space slightly reddish brown; indistinct, brown inverted triangular mark on head starting from inter-upper eyelid space and extending posteriorly; dorsum reddish brown, pair of broad dark brown stripes on dorsum, inwardly curved and outer margins diffused toward flank, starting from posterior end of upper eyelid, extending up to groin; tip of tubercles on head, upper eyelid, dorsum and flank white; lateral aspect of head pale greyish brown with brown mottling on it, small irregular white and faint brown patches on lips; supratympanic fold cream coloured, lower end broad, faint brown stripe in front of supratympanic fold staring from posterior corner of the eye to angle of jaw; lateral aspect trunk pale greyish brown with pinkish tinge and brown mottling on it; few large white patches on groin, ventrolateral aspect of flank and axilla; lower arm dorsally orange yellow, forearms and hands pale brown; a slightly darker crossbar on forearm; finger disc yellow, brown mottling on fourth finger disc; hind limb pale brown, short dark brown crossbars on thigh, tibia, and tarsus, base of thigh dorsally pale yellowish, tibio-tarsal articulation and outer lateral aspect of tarsus reddish brown; disc of inner three toes yellow; ventrally gular region with brown and white mottling, abdomen with irregular white patches and brown mottling. Colouration in preservative. Dorsally head pale brown; upper eyelid dark grey; a slightly darker greyish brown reversed triangular mark on head, staring between upper eyelids extending posteriorly, posterior end of the marking diffused; loreal region slightly darker, remaining lateral aspect of head paler; dorsum anteriorly pale brown, pair of pale cream coloured broad stripes, inwardly curved, both stripes merge and diffused posteriorly; forelimb, hindlimb, and digital discs dorsally pale yellowish with brown mottling; faint brown crossbars on forearm, thigh, and tibia. Ventrally pale yellowish with brown mottling. Morphological variation. Detailed morphometric variations are provided in Table S12. In addition, pair of stripes on dorsum prominent in the paratypes than holotype; tubercles behind upper eyelid and spinules on dorsum prominent in WII-ADA1541 than that of other paratypes and holotype; crossbar on forearm and tibia prominent in WII-ADA1542 than that of other type specimens; skin on dorsal aspect of snout and head shagreen in WII-ADA1540 and WII-ADA1541; snout tip slightly more pronounced in WII-ADA1541 than holotype and other paratypes. Morphological comparison. Raorchestes boulengeri sp. nov. differs from R. andersoni by head length being equal to width (vs. head length less than width), position nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. annandalii by presence of dark brown and white patches on groin (vs. no pattern on groin), presence of dense spinules on dorsum (vs. scattered tubercles on dorsum); it differs from R. cinerascens nov. comb. by snout length being greater than inter-upper eyelid width (vs. snout length equal to inter-upper eyelid width), position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. dulongensis by head length being equal to head width (vs. head longer than its width), nuptial pad present on first finger in males (vs. nuptial pad absent); it differs from R. garo by smaller body size, SVL 17.5–19.1 mm in adult males (vs. SVL 19.9–26.9 mm in adult males); it differs from R. hekouensis by presence of nuptial pad only on first finger (vs. nuptial pad present on first and second finger); it differs from R. hillisi and R. menglaensis by head length being equal to head width (vs. head longer than wide), snout length being less than or equal to eye length (vs. snout length greater than eye Boruah B et al.: Revision of bush frogs from northeast India 572 length); it differs from R. huanglianshan by inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than or equal to eye length); it differs from R. jadoh by larger body size in adult males, SVL 17.5–19.1 mm (vs. SVL 13.6–14.0 mm), and inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length), and thigh length being greater than tibia length (vs. thigh length less than tibia length); it differs from R. leiktho by larger body size in adult males, SVL 17.5–19.1 mm (vs. SVL 15.7–15.8 mm), position of nostril equidistant from eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. longchuanensis and R. yadongensis by inter-upper eyelid width being smaller than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by inter-upper eyelid width being smaller than eye length (vs. inter-upper eyelid width greater than or equal to eye length); it differs from R. mindat by presence of comparatively smaller white patches on groin (vs. enlarged black and white patches present on groin), absence of white patches on lateral aspect of thigh (vs. enlarged white patches on lateral aspect of thigh); it differs from R. parvulus by thigh length greater than tibia length (vs. thigh length smaller than or equal to tibia length), three crossbars present on thigh and tibia (vs. one on thigh and one or two on tibia); it differs from R. rezakhani by head length being equal to width (vs. head wider than long), snout length being greater than inter-upper eyelid width (vs. snout length less than or equal to inter-upper eyelid width); it differs from R. shillongensis by presence of dense spinules on back (vs. skin on dorsum moderately or heavily tuberculated); it differs from R. tytthus nov. comb. by snout length being less than or equal to eye length (vs. snout longer than eye length), position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); morphologically R. boulengeri sp. nov. is close to R. mawsynramensis sp. nov. A detailed morphological comparison of this species with its congeners is summarized in Table 1. Acoustics. The calls of R. boulengeri sp. nov. recorded in its type locality on 2 June 2022 at 18:15 hrs at an ambient temperature of 25.9°C. The call description is based on 40 calls from the holotype (WII-ADA1539). The calls are single type, non-pulsatile (Fig. 24), emitted as a single call at the beginning and gradually modified in groups (2 calls per group). The mean call duration is 25.03 ± 3.48 ms (20–31 ms) with a rise time of 1 ms and fall time of 24.1 ± 3.47 ms (20–30 ms). The mean interval between calls is 187.06 ± 13.18 ms (173–216 ms) when calls were emitted in groups. The dominant frequency is 3740.33 ± 20.81 Hz (3703.7–3789.8 Hz). The call of R. boulengeri sp. nov. differs from the call of its sister species R. mawsynramensis sp. nov. by the following characters: call duration of R. boulengeri sp. nov. is generally longer, 20–31 ms (vs. call duration 13–20 ms), inter-call interval is lower, 173– 216 ms (vs. inter-call interval 1127–2133 ms), and peak frequency range is lower, 3703–3789 Hz (vs. 4263–4608 Hz). A detailed comparison of the advertisement calls with those of the congeners is presented in Table 2. Figure 27. Raorchestes boulengeri sp. nov. A–C Holotype (WII-ADA1539), A dorsal view and B ventral view in preserved condition, C holotype in life. D–F Paratype (WII-ADA1542) in preserved condition, D dorsal view, E ventral view, F lateral view of head. Scale bar = 10 mm. Vertebrate Zoology 75, 2025, 517–625 573 Phylogenetic relationship and genetic divergence. Raorchestes boulengeri sp. nov. is sister to R. mawsynramensis sp. nov. (Figs 2, 3). The genetic divergence between these two species is 2.5–2.9% in the 16S, 3.9–4.4 in the cyt b, and 3.6–3.9% in the COI genes. The genetic divergence of R. boulengeri sp. nov. with other congeners varied between 3.4–9.8% in the 16S, 9.3–18.0% in the cyt b and 6.0–14.6% in the COI genes (Table S7A–C). Etymology. This species is named after George Albert Boulenger for his contribution to Indian herpetology, particularly bush frogs. Suggested common name. Boulenger’s bush frog. Distribution and natural history. Raorchestes boulengeri sp. nov. is currently known only from the type locality (Fig. 25A). Calling individuals of this species were recorded on shrubs and bamboo thickets in a small isolated forest patch. The forest patch was surrounded by grasslands. A small stream was present approximately 300 m west of the forest. Other sympatric anuran species recorded in the area were Amolops sp. and Minervarya sp. Raorchestes barakensis sp. nov. https://zoobank.org/52117744-1919-4F83-A8540A72C30F7935 Figure 28; Tables 1, 2, S12 Holotype. An adult male (WII-ADA612) collected by BB on 18 April 2019 from Maruwacherra (24.973744°N, 92.768593°E, elevation 50 m a.s.l.), Cachar District, Assam, India. Paratypes. Six adult males (WII-ADA611, WIIADA613– WII-ADA617). Collection details are same as for the holotype. Referred material. Three adult males (WII-ADA862, WII-ADA863 and WII-ADA865) collected by BB and AD on 2 August 2021 from Aramsangram (25.8312°N, 94.8731°E, elevation 1460 m a.s.l.), approximately 1.6 km (aerial distance) northeast to Pungro, Kiphire District, Nagaland; one adult male (WII-ADA942) collected by BB, NGP and AD on 4 September 2021from Hmuifang (23.45357°N, 92.75236°E, elevation 1500 m a.s.l.), Aizawl District, Mizoram; one adult male (WII-ADA1050) collected by BB, NGP and AD on 13 September 2021 from Phuldungsei (23.53537°N, 92.41584°E, elevation 780 m a.s.l.), Dampa Tiger Reserve, Mamit District, Mizoram; seven adult males (WII-ADA1335, WII-ADA1340, WII-ADA1346–WII-ADA1350) collected by BB and AD on 13 May 2022 from Motijheel Trail (27.49963°N, 96.33256°E, elevation 370 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh; three adult males (WII-ADA1451–WII-ADA1453) collected by BB, VJ and AD on 20 May 2022 from Gibbons Land (27.50168°N, 96.33169°E, elevation 350 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh; two adult males (WII-ADA1643 and WIIADA1644) collected by BB on 25 July 2022 from Lamdan (24.5954°N, 93.70851°E, elevation 1270 m a.s.l.), Churachandpur District, Manipur; one adult male (WIIADA3207) collected by RNV and SD on 5 May 2023 near M’Pen village (27.50166°N, 96.32147°E, elevation 370 m a.s.l.), Changlang District, Arunachal Pradesh. Diagnosis. Small sized Raorchestes, SVL 16.7–21.0 mm in adult males; head length equal to or less than width (HL/HW = 0.89–1.01); snout length less than or equal to eye length (SL/EL = 0.82–1.03); nostril equidistant between eye and snout tip or slightly closer to snout tip; internarial distance less than or equal to inter-upper eyelid width (IN/IUE = 0.74–1.0) and greater than upper eyelid width (UEW/IN = 0.7–0.91); inter-upper eyelid width smaller than eye length (IUE/EL = 0.72–0.96); vomerine teeth absent; nuptial pad present on first finger in males; blunt tubercles on head, upper eyelid, behind upper eyelid, forearm, thigh, tiba, and tarsus; spinules on dorsum intermixed with blunt tubercles; a brown “)-(“ marking on dorsum; brown crossbars on forearm, thigh and tibia; disc on inner two fingers yellow; bony projection on humerus on ventral aspect. Description of the holotype. Holotype in good condition except for an incision on abdomen towards left side and another incision on ventral side of right thigh. Adult male with vocal sac, 20.4 mm in SVL; head length equal to width; snout rounded in dorsal view, truncated in lateral view and slightly protruding beyond lower jaw; canthus rostralis smooth, obliqued; loreal region concave; snout length equal to eye length; nostril oval, laterally positioned, obliquely oriented, slightly closer to snout tip than eye (NS/EN = 0.86); internarial distance slightly smaller than inter-upper eyelid width (IN/IUE = 0.88) and greater than upper eyelid width (UEW/IN = 0.86); internarial region slightly concave; area between nostril and snout tip slightly concave; tympanum distinct, round, its diameter less than one third of eye length; tongue posteriorly wide and deeply notched; vomerine teeth absent; choanae round; pair of internal slit like openings present on lower jaw towards edges; symphysial knob present on lower jaw; habitus stout, half of the snout-vent length. Forelimbs slender, hand length slightly less than forearm length (HAL/FAL = 0.94), digit with rounded disc; circum-marginal groove present on each disc; third finger longest, relative length of fingers = I<II<IV<III; disc on third finger largest and slightly wider than tympanic diameter (HTYD/FIIID = 0.73); webbing on hand absent; subarticular tubercles distinct, enlarged and round except proximal ones on third and fourth fingers which are indistinct and smaller; subarticular tubercle formula on fingers I–IV = 1:1:2:2; palmar tubercles indistinct; bony projection on humerus directed ventrally (Fig. 25) Hindlimbs slender; thigh length half of snout-vent length (TL/SVL = 0.51); tibia length nearly equal to thigh Boruah B et al.: Revision of bush frogs from northeast India 580 larged yellow spots on thigh); differs from R. hekouensis by larger body size, SVL 18.0–21.1 mm in adult males (vs. SVL 16.1–17.5 mm in adult males), nuptial pad present only on first finger (vs. nuptial pad present on first and second finger); it differs from R. hillisi by larger body size, SVL 18.7–21.2 mm in adult males and SVL at least up to 23.1 mm in adult female (vs. SVL 14.5–17.7 mm in adult males and 17.5 in adult female), head length equal to width or slightly wider than long (vs. head longer than wide), dark brown patch on groin absent (vs. present); it differs from R. huanglianshan by dark brown patch on groin absent (vs. present), snout length being equal to or less than eye length (vs. snout length greater than eye length); it differs from R. jadoh by larger body size in adult males, SVL 18.0–21.1 mm (vs. 13.6–14.0 mm), and inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length), inter-upper eyelid width less than eye length (vs. inter-upper eyelid width greater than or equal to eye length), and thigh length being greater than or equal to tibia length (vs. thigh length less than tibia length); it differs from R. kempiae by dorsal skin, scattered tubercles present dorsum (vs. dorsal skin of dorsum with spinules and blunt tubercles), absence of marking on groin (vs. short brown strip present on groin); it differs from R. longchuanensis by inner-upper eyelid being smaller than eye length (vs. inter-upper eyelid greater than eye length); it differs from R. leiktho by larger body size in adult males, SVL Figure 31. Comparative spectrograms and oscillograms illustrating representative calls of three species of Raorchestes. A, B Oscillograms, C spectrogram, D power spectrum. The call marked with an arrow on top in A is expanded in B. Vertebrate Zoology 75, 2025, 517–625 581 18–21.1 mm (vs. SVL 15.7–15.8 mm); it differs from R. malipoensis by its large body size, SVL 18.7–21.2 mm in adult males and SVL at least up to 23.1 mm in adult female (vs. SVL 14.6–17.7 mm in adult males and 18.3–19.3 in adult females), black patches on groin and lateral aspect of thigh absent (vs. present); it differs from R. menglaensis by head length being equal to width or slightly wider than long (vs. head longer than wide), dark brown or black blotch on groin absent (vs. present); it differs from R. mindat by absence of dark or white patches on groin (vs. enlarged black and white patches present on groin), no white patches on lateral aspect of thigh (vs. enlarged white patches on lateral aspect of thigh); it differs from R. boulengeri sp. nov. and R. mawsynramensis sp. nov. in having relative smooth skin with scattered tubercles on dorsum (vs. dense spinules on dorsal aspect of head, dorsum, and limbs), being nostril closer to snout tip than eyes (vs. nostril equidistant from eyes and snout tip in R. boulengeri sp. nov. and R. mawsynramensis sp. nov.); differs from R. orientalis sp. nov. by presence of scattered tubercles on dorsum (vs. dense spinules on dorsum), presence of broad dark brown crossbar on thigh and tibia (vs. three crossbars on thigh and tibia), presence of pair of concave stripes on dorsum (vs. a “)-(“ mark on dorsum); it differs from R. parvulus snout sub ovoid to nearly acute (vs. snout rounded), absence of marking on groin (vs. dark brown marbling enclosing a whitish blotch on groin); it differs from R. rezakhani by presence of single broad crossbar on each thigh and tibia (vs. at least three narrow dark brown crossbars on each thigh and tibia), absence of brown patch on groin (vs. a short brown streak present on groin); it differs from R. shillongensis by absence of marking on groin (vs. dark brown patch with white crown shaped mark or diffused brown patch on groin); it differs from R. tytthus nov. comb. by snout length being equal to or less than eye length (vs. snout length greater than eye length), absence of spot or marking on groin (vs. a large white spot on groin); it differs from R. yadongensis by absence of white patches on chest and abdomen (vs. present). A detailed morphological comparison is provided in Table 1. Acoustics. The calls of R. narpuhensis sp. nov. were recorded in Narpuh Wildlife Sanctuary, Meghalaya on 29 May 2022 between 19:00–21:00 hrs at an ambient temperature of 27.5°C. The call description is based on 40 calls from two individuals (WII-ADA1509 and WII-ADA1510). Calls are of a single type, non-pulsatile, emitted at regular intervals and not in groups (Fig. 31). The mean call duration is 18.7 ± 4.02 ms (13–25 ms) with a rise time of 1 ms and a fall time of 17.68 ± 3.83 ms (12–24 ms). The mean call interval between calls is 670.17 ± 85.57 ms (544–823 ms). The dominant frequency is 3954.57 ± 165.48 Hz (3574.5–4134.4 Hz). A detailed comparison of the advertisement calls with those of the congeners is presented in Table 2. Phylogenetic relationship. Raorchestes narpuhensis sp. nov. is sister to R. lawngtlaiensis sp. nov. (UFB 100, PP 1.0; Figs 2, 3) with genetic divergence of 2.3–2.7% in the 16S, 8.1–8.2% in the cyt b and 8.7–8.9% in the COI genes. The closest aerial distance between type localities of these two species is 293 km. Raorchestes narpuhensis sp. nov. has genetic divergence of 5.1–10.0% in the 16S, 13.7–20.8% in the cyt b and 8.7–15.7% in the COI genes with the other members of the genus (Table S7A–C). Etymology. The specific epithet is a toponym derived from the name “Narpuh Wildlife Sanctuary” in Meghalaya State where the type series were collected. Suggested common name. Narpuh bush frog. Distribution and natural history. Currently Roarchestes narpuhensis sp. nov. is known from its type locality in and around Narpuh Wildlife Sanctuary, and in Riwai of Meghalaya (Fig. 19A). We encountered calling males and a single female at ~1–2 m above ground perching on shrubs and on small bamboo leaves, Zingiber sp. on hill slopes (Fig. 20H). Other sympatric species found with the new species were Chirixalus sp. and Polypedates cf. himalayensis. Raorchestes lawngtlaiensis sp. nov. https://zoobank.org/CD636615-6E5F-46AC-A69A-F1D656DEF592 Figure 32; Tables 1, 2, S12 Holotype. WII-ADA947, an adult male collected by AD, BB and NGP on 6 September 2021 from Ngengpui Wildlife Sanctuary (22.48498°N, 92.75653°E, elevation 210 m a.s.l.), Lawngtlai District, Mizoram, India. Paratype. An adult male (WII-ADA946) collected by AD, BB and NGP on 6 September 2021 from Ngengpui Wildlife Sanctuary (22.48906°N, 92.75678°E, elevation 210 m a.s.l.), Lawngtlai District, Mizoram. Diagnosis. A small sized Raorchestes, SVL = 18.1–19.7 mm in males, female unknown; snout rounded, slightly less than eye length; nostril closer to snout tip than eye; head slightly wider than long or equal proportions; inter-upper eyelid width less than eye length; vomerine teeth absent; nuptial pad present on first finger in males; dorsal aspect pale yellowish brown; “)(“ shaped broad dark brown marking on dorsum, posterior ends of this marking bordered by irregular white spots; an oblique dark brown stripe bordered with white spots on flank; dark crossbars bordered with white spots on forelimb and on hindlimb; irregular small white spots on dorsal aspect of head; dorsum and limb; tympanic region dark brown; a dark brown streak ventral to eye bordered with white streak; groin, axilla, hind arm, lateral side of thigh, finger and toe discs yellow; irregular white flecks on chest and abdomen; forelimb and hindlimb dark brown; gular region yellowish brown. Boruah B et al.: Revision of bush frogs from northeast India 582 Description of the holotype. Adult male, SVL 18.1 mm; head wider than long (HL/HW = 0.95); snout rounded with a blunt tubercular projection at tip, truncated in lateral view, snout length less than eye length (SL/EL = 0.83); nostril oval, equidistant between eyes and snout tip; inter-upper eyelid width greater than inter narial distance (IN/IUE = 0.76); internarial distance equal to upper eyelid width; eye length nearly half of head length (EL/ Figure 32. Raorchestes lawngtlaiensis sp. nov. A–E Holotype (WII–ADA947) in preservative and F, G holotype in life; A dorsal view, B ventral view, C lateral view of head, D ventral view of right hand, E ventral view of right foot; F dorsolateral view, G ventral view. H, I Paratype (WII-ADA946) in preservative and J–M in life; H dorsal view, I ventral view, J, K dorsolateral view, L ventral view, M groin. Scale bar = 10 mm. Vertebrate Zoology 75, 2025, 517–625 583 HL = 0.46); canthal ridge distinct, oblique; loreal slightly concave; tympanum rounded, distinct; tympanic diameter one fifth of eye length; supratympanic fold distinct; vomerine teeth absent; choanae round; tongue notched medially at posterior end and with sparsely distributed flat granules. Forelimbs slender, forearm shorter than hand length (FAL/HAL = 0.86); third finger longest, relative length of fingers = I<II<IV<III; finger with rounded disc, disc with circum-marginal groove; disc on second, third and fourth finger wider than horizontal tympanic diameter; subarticular tubercles round and distinct except proximal ones on third and fourth fingers; palmar tubercles indistinct; nuptial pad present on first finger. Hindlimbs slender, thigh length longer than shank length (TBL/TL = 0.92) and foot length (FOL/TL = 0.85); shank longer than foot length (FOL/TBL = 0.92); fourth finger longest toes, relative length of toes = I<II<III<V<IV; toe with rounded disc, disc with circum-marginal groove, disc width of fourth toe slightly less than that of third toe; subarticular tubercles round and distinct except proximal ones on fourth and fifth toes; inner metatarsal tubercle present, longer than horizontal tympanic diameter, outer metatarsal tubercle absent. Skin on dorsal aspect of head smooth with scattered spinules; distinct spinules on upper eyelid; few granular tubercles behind angle of jaw; numerous spinules on dorsum, above supratympanic fold and flank; limb smooth dorsally; throat, chest, abdomen and ventral aspect of thigh granular; tibia and tarsus smooth. Colouration in life. Dorsal aspect of head and dorsum pale yellowish brown; slightly dark brown patch on snout and posterior part of head; tubercles on snout, upper eyelid and posterior part of head white; lateral aspect of head pale yellowish brown; narial region dark brown; alternative dark brown and white bands on upper jaw; white speckles on angle of jaw and mandibular region; tympanic region dark brown; few irregular sized white spots on dorsum; a pair of concave dark brown stripes on dorsum, posteriorly prominent and edged with white speckles; another similar short stripe on flank; white flecks on axilla; irregular white spots on forelimb; finger discs yellow; white spots of irregular size and shape on hindlimb; an indistinct broad crossbar on thigh and tibia; groin and lateral aspect of thigh pale yellow; ventral aspect of head yellowish with dense brown and white marbling, few small white patches along lower jaw; irregular white flecks on chest, abdomen, forelimb and hind limb; finger and disc pale yellow; yellow tinge on toe, first toe on left side yellow. Colouration in preservative. Dorsal and ventral colouration similar with that of colouration in life except that white spots visible in life are not visible in preserved condition; brown reticulation on pale-cream coloured background on chest and abdomen. Morphological comparison. Raorchestes lawngtlaiensis sp. nov. differs from R. andersoni by position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. annandalii by internarial distance being equal to upper eyelid width (vs. internarial distance greater than upper eyelid width), snout length being less than eye length (vs. snout length equal to or greater than eye length); it differs from R. barakensis sp. nov. by absence of bony projection on humerus (vs. bony projection on humerus present); it differs from R. boulengeri, R. kempiae, R. orientalis sp. nov., and R. shillongensis sp. nov. by internarial distance being equal to upper eyelid width (vs. internarial distance being greater than upper eyelid width); it differs from R. cinerascens nov. comb. by presence of a single broad crossbar on thigh and tibia (vs. three crossbars on thigh and tibia); it differs from R. dulongensis by snout length being less than eye length (vs. snout length equal to eye length); it differs from R. garo by smaller body size, SVL 18.1–19.7 mm in adult males (vs. SVL 19.9–26.9 in adult males); it differs from R. hekouensis, R. hillisi and R. malipoensis by larger body size, SVL 18.1–19.7 mm in adult males (vs. SVL 16.1–17.5 mm in R. hekouensis, 15.9–17.7 mm in R. hillisi and 14.6–17.7 in R. malipoensis); it differs from R. hillisi by snout length being less than eye length (vs. snout length greater than eye length); it differs from R. huanglianshan by snout length being less than eye length (vs. snout length greater than eye length); it differs from R. jadoh by larger body size in adult males, SVL 18.1–19.7 mm (vs. 13.6–14.0 mm), and inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. jakoid by snout length being less than eye length (vs. snout length greater than eye length), inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than or equal to eye length), and thigh length being greater than or equal to tibia length (vs. thigh length less than tibia length); it differs from R. leiktho by larger body size in adult males, SVL 18.1–19.7 mm (vs. SVL 15.7–15.8 mm); it differs from R. longchuanensis by inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than or equal to eye length); it differs from R. mawsynramensis sp. nov. by presence of moderately dense spinules on dorsum (vs. comparatively denser spinules on dorsum), presence of dark brown stripe edged with white spots on flank (vs. absent); it differs from R. menglaensis by snout length being smaller than eye length (vs. snout length longer than eye length), head length being equal to or slightly smaller than its width (vs. head longer than its width); it differs from R. mindat by presence of dark brown band bordered with white spots on groin (vs. enlarged black and white patches present on groin), by absence of white patches on lateral aspect of thigh (vs. enlarged white patches on the lateral aspect of thigh); it differs from R. narpuhensis sp. nov. by internarial distance being equal to upper eyelid width (vs. internarial distance greater than upper eyelid width), presence of dark brown stripe edged with white spots on groin (vs. no pattern on groin); it differs from R. parvulus by thigh Boruah B et al.: Revision of bush frogs from northeast India 584 Figure 33. Habitat at the type localities of Raorchestes species in northeast India. A Lowland forest stream at the type locality of R. lawngtlaiensis sp. nov. in Ngengpui WLS; B landscape view of Mehao WLS from Abango, type locality of R. dibangensis sp. nov. in Abango; C. hill stream and riparian habitat at the type locality of R. shillongensis in Malki, Shillong; D landscape view of the hills at Pumdunlong, the type locality of R. monolithus sp. nov. at Willong Khullen Village; E landscape view of hills and lowland areas at Khonoma, the type locality of R. khonoma sp. nov.; F forest cover at Bompu, Eaglenest WLS at the type locality of R. eaglenestensis sp. nov.; G hill stream and forest cover at Abor hills, habitat of R. magnus sp. nov.; H landscape view of Abor hills and adjacent lowland areas, habitat of R. arunachalensis sp. nov. Vertebrate Zoology 75, 2025, 517–625 585 being longer than tibia (vs. thigh shorter than or equal to tibia length); it differs from R. rezakhani by presence of dark brown stripe edged with white spots on flank (vs. no brown stripe on flank); it differs from R. tytthus nov. comb. by snout length being less than eye length (vs. snout length greater than eye length); it differs from R. yadongensis by inter-upper eyelid width being less than eye length (vs. inter-upper eyelid width greater than eye length), by snout length being less than eye length (vs. snout length equal to eye length). A detailed morphological comparison is given in Table 1. Phylogenetic relationship and genetic divergence. Raorchestes lawngtlaiensis sp. nov. is sister to R. narpuhensis sp. nov. (Figs 2, 3). The genetic divergence with other congeners included in this study is 2.3– 9.3% in the 16S, 13.9– 21.0% in the cyt b and 13.9– 21.0% in the COI genes (Table S7A–C). Etymology. The specific epithet is a toponym derived from the name “Lawngtlai” District in Mizoram State where the type locality of this species lies. Suggested common name. Lawngtlai bush frog. Distribution and natural history. Raorchestes lawngtlaiensis sp. nov. is currently known from its type locality in Ngengpui Wildlife Sanctuary, Lawngtlai, Mizoram (Fig. 19A). The holotype was found calling on a leaf approximately at one metre height above ground along a forest trail at around 23:00 hrs. The paratype was recorded while it was calling from a bamboo branch approximately 1.5 m above ground at around 20:15 hrs at the edge of a small stream of approximately two meters in width (Fig. 33A). Raorchestes nasuta sp. nov. https://zoobank.org/F55DCD22-E950-431A-B542-F145DCC252C9 Figure 34; Tables 1, 2, S12 Holotype. An adult male (WII-ADA3388) collected by RNV on 12 June 2023 from Ranijheel (27.53903°N, 96.4888°E, elevation 910 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India. Paratypes. Two adult males (WII-ADA3398 and WIIADA3399) collected by RNV on 13 June 2023 from Bulbulia (27.53872N, 96.4763E, elevation 880 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh. Referred Material. Two adult males (WII-ADA3216 and WII-ADA3218) collected by RNV and SD on 10 May 2023 from Hornbill (27.53810°N, 96.44037°E, elevation 660 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh. Diagnosis. A small sized Raorchestes, SVL 17.0–19.9 mm in adult males, female unknown; head longer than wide; snout acute with dermal projection on snout tip; snout length equal to eye length; inter-upper eyelid width less than or equal to eye length (IUE/EL = 0.88–0.96); nostril equidistant between eye and snout tip; horn like dermal projection on edge of upper eyelid; an hour-glass shaped dark brown mark starting on inter-upper eyelid space and extending to dorsum; bright yellow patches on groin and thigh; finger and toe disc yellow. Description of the holotype. Holotype well preserved except for an incision on the ventral side of right thigh. Adult male, SVL 17.9 mm; head longer than wide (HW/ HL = 0.9); snout acute in dorsal and lateral view as a dermal projection present on snout tip, protruding beyond lower jaw in ventral view; snout length equal to eye length and slightly greater than inter-upper eyelid width (IUE/ SL = 0.85); symphysial knob present on lower jaw; narial region protruding; nostril oval, laterally positioned and obliquely oriented, equidistant between eye and snout tip; slightly concave on dorsal aspect of snout; canthus rostralis rounded, vertical; loreal concave; eye moderate in size (EL/HL = 0.37); internarial distance nearly equal to inter-upper eyelid width (IN/IUE = 0.91) and greater than upper eyelid width (UEW/IN = 0.86); tympanum indistinct, round, one third of eye length (HTYD/EL = 0.31); supratympanic fold distinct; vomerine teeth absent; choanae round; tongue posteriorly deeply notched and the two lobes are acute; pair of internal vocal sac openings on lower jaw; habitus less than half of snout-vent length (AG/SVL = 0.46). Forelimbs slender; forearm nearly equal to hand length (FAL/HL = 0.96); relative length of fingers = FI<FII<FIV<FIII; rounded disc on finger, disc on finger III and IV wider than tympanic diameter; circum-marginal groove on each disc; rudimentary webbing present between fingers; palmar tubercles indistinct; subarticular tubercles round, lower subarticular tubercle on finger III and IV small and indistinct; enlarged, fine granular nuptial pad on first finger. Hindlimbs slender; thigh longer than tibia (TBL/TL = 0.89) and half of snout-vent length (TL/SVL = 0.5); relative length of toes = TI<TII<TIII<TV<TIV; rounded disc on toe, smaller than those of fingers; circum-marginal groove present each disc; subarticular tubercles distinct in live condition, proximal subarticular on fourth and fifth toes indistinct; inner metatarsal tubercle present, its length equal to width of discs of toes II–V; very thin dermal fringe along fifth toe; webbing moderate, reaching beyond second subarticular tubercle on fourth toe. Skin on dorsal aspect of snout and head smooth (shagreen in live condition); indistinct tubercles on upper eyelid, a horn like tubercle on edge of each upper eyelid; tubercles on angle of jaw; skin on dorsum (shagreen in live condition) with spinules, scattered on middle and dense towards dorsolateral aspect; a weak mid-dorsal dermal ridge visible in live condition starting from snout and becoming diffused posteriorly; flank smooth; dorsal aspect of forelimb and hindlimb smooth; throat and chest Boruah B et al.: Revision of bush frogs from northeast India 586 smooth; abdomen and thigh granular; tibia and tarsus smooth. Colouration in life. Dorsal aspect of snout and top of head, dorsum brown; an hourglass shaped dark brown marking starting at inter-upper eyelid space and covering posterior half of upper eyelid extending to dorsum, becoming diffused posteriorly; a diffused dark brown broad stripe along supratympanic fold; another similar stripe on loreal region reaching snout tip; irregular pale cream coloured white spots on upper jaw; two yellow spots on groin on each side and inner lateral aspect of thigh; on outer lateral aspect of thigh yellow patches barely visible; a broad cross bar on each thigh and tibia barely visible; disc on digits yellow; ventral aspect of head, chest, abdomen and thigh brown, paler than dorsal aspect; dense dark brown mottling on chin, throat with few white flecks on anterior part of the jaw; brown mottling on ventral aspect of forelimb chest, abdomen and thigh not dense; irregular white flecks on forearm, thigh, tarsus and foot; granules on anterior to middle of the abdomen with white flecks; brown mottling on foot dense; Colouration in preservative. Colouration darker than in life; marking on head and dorsum visible; mandibular region dark brown; dorsal aspect of distal half of forearm and hand dark brown; knee dark brown; crossbars on thigh and tibia distinctly visible; one broad cross bar on each thigh and two on each tibia; disc on digits pale cream coloured with brown mottling; dark brown patch around vent; chin and throat brown; chest, abdomen and ventral aspect of thigh pale cream coloured with brown flecks; forearm, tibia, tarsus, and feet brown; yellow spots on groin and thigh and white flecks on abdomen not visible. Morphological variation. Detailed morphometric variations are given in Table S12. Additionally, yellow spots on groin and thighs vary among individuals (Fig. 34). For example, WII-ADA3216 has yellow patches on base of lower arm, ventral aspect of thigh and tibia; distinct enlarged yellow patches on outer lateral aspect of thigh; yellow patches on groin much enlarged unlike holotype; a tubercle on inter-upper eyelid space. Dorsal marking on head and dorsum in WII-ADA3216 distinct in preserved condition and barely visible in WII-ADA3218, WIIADA3398 and WII-ADA3399. Brown mottling on the ventral side in paratypes is not as dense as in holotype. Morphological comparison. Raorchestes nasuta sp. nov. differs from its congeners by its acute snout shape; further it differs from R. andersoni by position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. annandalii, R. boulengeri sp. nov., and R. kempiae by presence of enlarged yellow patches on groin and thigh (vs. absent); it differs from R. barakensis sp. nov. by head being longer than wide (vs. head length less than or equal to width), enlarged yellow patches present on groin (vs. enlarged brown patch present on groin), by presence of dark brown hourglass shaped pattern on dorsum (vs. pair of concave dark brown stripes present on dorsum); it differs from R. cinerascens nov. comb. by snout length being equal to eye length and longer than inter-upper eyelid width (vs. snout length less than eye length and equal than inter-upper eyelid width); it differs from R. dulongensis by position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye), enlarged yellow spots present on groin and thigh (vs. absent); it differs from R. garo by presence of enlarged yellow patches on groin and thigh (vs. dark brown patches with or without yellow spots present); it differs from R. hekouensis by head being longer than wide (vs. head wider than long), snout being longer than inter-upper eyelid width (vs. snout length less than or equal to inter-upper eyelid width), nuptial pad present only on first finger (vs. nuptial pad present on first and second finger); it differs from R. hillisi and R. menglaensis by position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye), snout length being equal to eye length (vs. snout length greater than eye length); it differs from R. huanglianshan by head being longer than wide (vs. head length less than or equal to width), by snout length being equal to eye length (vs. snout length greater than eye length); it differs from R. jadoh by larger body size in adult males, SVL 17.0–19.9 (vs. SVL 13.6–14.0 mm); itr differs from R. jadoh and R. jakoid snout acute (vs. snout rounded), by position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye), and enlarged yellow patches present on groin and thigh (vs. absent); it differs from R. lawngtlaiensis sp. nov. by head being longer than wide (vs. head length equal to or smaller than width), by snout length being equal to eye length (vs. snout length less than eye length); it differs from R. leiktho by larger body size in adult males, SVL 17.0–19.9 mm (vs. SVL 15.7–15.8 mm), an hourglass shaped pattern present on dorsum (vs. absent); it differs from R. longchuanensis by inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by head being longer than wide (vs. head wider than long), by snout being longer than inter-upper eyelid width (vs. snout length less than or equal to inter-upper eyelid width); it differs from R. mawsynramensis sp. nov. and R. shillongensis by head being longer than wide (vs. head length less than or equal to width), enlarged yellow patches present on groin and thigh (vs. absent); it differs from R. mindat by presence of yellow patches on groin and thigh (vs. enlarged black and white patches present on groin and thigh), an hourglass shaped pattern present on dorsum(vs. absent); it differs from R. narpuhensis sp. nov. by head being longer than wide (vs. head length less than or equal to width), by position of nostril equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. parvulus by thigh being longer than tibia (vs. thigh length smaller than or equal to tibia length); it differs from R. rezakhani by snout length being equal to eye length (vs. snout length greater than eye length), by head being longer than wide (vs. head wider than long); it differs from R. tytthus nov. comb. by head being longer than wide (vs. head length equal to width), snout length being equal to eye length Vertebrate Zoology 75, 2025, 517–625 587 (vs. snout length greater than eye length); it differs from R. yadongensis by head being longer than wide (vs. head wider than long), inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length). A detailed morphological comparison is provided in Table 1. Figure 34. Raorchestes nasuta sp. nov. A–D Holotype (WII-ADA3388) in preservative, A Dorsal view, B ventral view, C lateral view, D ventral view of right hand. E, F Paratype (WII-ADA3216) in preservative. G–J Holotype in life, G dorsolateral view, H ventral view, I dorsal view, J groin. K–O paratype (WII-ADA3216) in life, K dorsolateral view, L dorsal view of head, M ventral view, N groin, O posterior view of thighs. Scale bar = 10 mm. Photos (G–O) by Rajiv N.V. Boruah B et al.: Revision of bush frogs from northeast India 588 Phylogenetic relationship and genetic divergence. Raorchestes nasuta sp. nov. is sister to an undescribed species from Tibet and Adi hills, Arunachal Pradesh (UFB 100, PP 1.0; Figs 2, 3). These two lineages have a shallow genetic divergence of 1.5–2.0% in the 16S gene. The genetic divergence of R. nasuta sp. nov. with other congeners included in this study are 3.1–8.9% in the 16S, 9.1–19.2% in the cyt b and 3.2–14.8% in the COI genes (Table S7A–C). Etymology. The specific epithet is derived from the Latin word nose “Nasuta”, in reference to the prominent acute snout of this species. Suggested common name. Pointy-nosed bush frog. Distribution and natural history. Raorchestes nasuta sp. nov. is currently distributed within Namdapha Tiger Reserve in Ranijheel, Bulbulia and Hornbill on the northern bank of the Noa-Dihing River, Arunachal Pradesh, India between 600–1000 m a.s.l. elevation (Fig. 20A). Calling aggregation of the species was recorded between 18:00– 22:00 hrs on vegetation along streams and forest trails. Raorchestes dibangensis sp. nov. https://zoobank.org/03F4255C-EBDB-4925-92A6-AF654C29C440 Figure 35; Tables 1, 2, S12 Holotype. An adult male (WII-ADA1677) collected by BB on 7 August 2022 from Abango (28.09974°N, 95.89392°E, elevation 410 m a.s.l.), Lower Dibang Valley District, Arunachal Pradesh, India. Paratype. An adult male (WII-ADA1671) collected along with holotype from the same locality. Diagnosis. A small sized Raorchestes, SVL 19.6–21.8 mm in adult males, female unknown; head length equal to width; snout rounded, its length equal to or less than eye length; tympanum indistinct; small blunt tubercles on upper eyelid; spinules on middle of dorsum, above supratympanic fold, flank and sparsely present on limb; two indistinct crossbars on thigh and tibia; dorsum pale brown with a pair of faint concave stripes, posterior ends of these stripes distinct near groin; white bar present on inter-upper eyelid space in some individuals; small white spots visible on abdomen in life. Description of the holotype. Holotype well preserved except for an incision on underside of right thigh; small sized. Adult male with vocal sac, SVL 21.8 mm; head length equal to width; snout rounded in dorsal view and nearly truncated in lateral view, its length (2.9 mm) equal to eye length (2.9 mm); nostril obliquely oval in shape, laterally positioned and oblique, closer to snout tip than eye (NS/EN = 0.69); narial region raised; canthus rostralis smooth, obliqued; loreal region concave; internarial distance equal to inter-upper eyelid width and greater than upper eyelid width (UEW/IN = 0.68); tympanum indistinct, round, less than one third of eye length (HTYD/ EL = 0.28); supratympanic fold distinct; tongue posteriorly wide and deeply notched; small flat tubercles on tongue; choanae oval; vomerine teeth absent; a pair of slit like openings on lower jaw near angle of jaw; symphysial knob present on lower jaw. Habitus slender, dorso-ventrally flattened, less than half of snout-vent length (AG/SVL = 0.44); forelimb slender; hand length greater than forearm length (FAL/ HAL = 0.86); digit with rounded disc; circum-marginal groove present on each disc; third finger longest, relative length of fingers = I<II<IV<III; disc on third finger wider than tympanic diameter (HTYD/TIIID = 0.73); palmar tubercles barely visible; subarticular tubercles rounded, proximal ones on third and fourth finger smaller than distal ones and indistinct; no webbing among the fingers; finely granular nuptial pad on first finger; hindlimb slender; thigh longer than tibia (TBL/TL = 0.94) and nearly half snout-vent length (TL/SVL = 0.48); fourth toe longest; toe with rounded disc, disc width equal to those of fingers; relative length of toes = I<II<III=V<IV; no dermal fringe along fifth toe; webbing slight, not reaching the second subarticular tubercle on fourth toe; small inner metatarsal tubercle present, outer one absent; subarticular tubercles round, proximal subarticular tubercles on toe III–V barely visible; no supernumerary tubercles. Skin on dorsal aspect of head smooth; snout on dorsal aspect and upper eyelids shagreen; indistinct tubercles on upper eyelid; at least two blunt tubercles on mandibular region, behind angle of jaw; spinules on dorsolateral aspect of trunk and middle of dorsum, starting above posterior part of supratympanic fold, few scattered on anterior and posterior part of dorsum; flank, forelimb and hindlimb smooth on dorsal aspect; throat and chest smooth; gular skin loose; abdomen granular; thigh granular but not as distinct as on abdomen; tibia smooth on ventral aspect. Colouration in preservative. Dorsal aspect of head brown; pale white bar on inter-upper eyelid space followed by a slightly darker inverted triangular mark on head; upper eyelid dark grey; loreal region darker than dorsal aspect of head; supratympanic fold dark brown; dorsum darker than head, paler on flank; forelimb pale brown on dorsal aspect; a slight dark brown crossbar on forearm; a similar short bar on hand below fourth finger; hindlimbs pale brown dorsally, slightly darker towards knee; single dark brown cross bar on each thigh; a single cross bar on left tibia and two on right tibia; two crossbars on each tarsus, faint; a short dark brown bar on foot below fifth toe; area around vent darker; chin, throat, chest, abdomen, ventral aspect of limb, hand, and feet creamy white with brown mottling, chin towards the edge of lower jaw heavily mottled. Colouration in life. Head and body and limbs on top pale greyish brown; a broken pale white bar on inter-upper Vertebrate Zoology 75, 2025, 517–625 589 eyelid space; iris whitish with brown spots and irregular wavy brown lines, golden mottling on upper half of it; a pair of barely visible, faint brown concave stripes on dorsum; single faint brown crossbar on forearm; similar two crossbars on each thigh and tibia and single cross bar on tarsus towards distal end; disc on inner two fingers and inner two toes yellow; ventral aspect of head, abdomen and limbs pale flesh coloured with brown mottling; vocal sac pale yellow and pale semi-transparent,; white spots of irregular size on granules of abdomen; irregular white spots on thigh, tibia, tarsus, and forearm. Morphological variation. Morphometric details are given in Table S12. The paratype does not have a white bar on inter-upper eyelid space; crossbars on limbs not visible in preserved condition unlike holotype; lower jaw and chest heavily mottled with brown unlike holotype. Morphological comparison. Raorchestes dibangensis sp. nov. differs from R. andersoni by head length being equal to width (vs. head wider than length); R. annandalii by presence of dense spinules on dorsum (vs. skin on dorsum smooth); it differs from R. barakensis sp. nov. by absence of pattern on groin (vs. enlarged brown patch on groin), two indistinct crossbars present on thigh and tibia (vs. three narrow bands present on thigh and tibia), concave stripes on dorsum indistinct or not visible (vs. concave stripes on dorsum distinct); it differs from Figure 35. Raorchestes dibangensis sp. nov. A Dorsal and B ventral view of holotype (WII-ADA1677) in preserved condition. C–E paratype (WII-ADA1671) in preserved condition, C dorsal view, D ventral view, E lateral view of head. F Dorsolateral and G ventral view of holotype in life. Scale bar = 10 mm. Boruah B et al.: Revision of bush frogs from northeast India 596 dorsum); it differs from R. hillisi by larger body size in males, SVL 17.9–20.6 mm (vs. SVL 15.9–17.7 mm in males), by head being wider than long (vs. head longer than wide), by snout length being equal to or slightly less than eye length (vs. snout length longer than eye length), tympanum indistinct (vs. tympanum distinct), absence of dark stripes on dorsum (vs. a dark “)(“ shaped marking on dorsum); it differs from R. huanglianshan by snout length equal to or slightly less than eye length (vs. snout length greater than eye length), tympanum indistinct (vs. tympanum distinct), absence of dark marking on inter-upper eyelid space (vs. a brown triangular marking on inter-upper eyelid space), and by absence of “X” mark on dorsum (vs. a dark “X” mark on dorsum); it differs from R. jadoh and R. jakoid by snout length equal to inter-upper eyelid width (vs. snout length greater than inter-upper eyelid width), by nostril being equidistant between snout tip and eye (vs. nostril closer to snout tip than eye), and thigh length being greater than tibia length (vs. thigh length less than tibia length); it differs from R. kempiae by snout length being equal to inter upper eyelid width (vs. snout length greater than inter-upper eyelid width), inter-upper eyelid width being equal to eye length (vs. inter upper eyelid width smaller than eye length); it differs from R. lawngtlaiensis sp. nov. by inter upper eyelid width being equal to eye length (vs. inter upper eyelid width greater than eye length), internarial distance being greater than upper eyelid width (vs. internarial distance equal to upper eyelid width); it differs from R. leiktho by larger body size in adult males, SVL 17.9–20.6 mm (vs. SVL 15.7–15.8 mm); it differs from R. longchuanensis by smaller body size in males, SVL 17.9–20.6 mm (vs. SVL 21.4–23.9 mm in males), by inter upper eyelid width being equal to eye length (vs. inter upper eyelid width greater than eye length), tympanum indistinct (vs. distinct); it differs R. mawsynramensis sp. nov. by dorsal skin smooth with few scattered spinules on it (vs. dense spinules on dorsum), absence of “)-(“ on dorsum (vs. present), marking absent on inter-upper eyelid space absent (vs. present); it differs from R. menglaensis by head being wider than long (vs. head longer than wide), snout length being equal to or slightly less than eye length (vs. snout length longer than eye length),, no “X” shaped marking on dorsum (vs. a “X” marking on dorsum present), tympanum indistinct (vs. tympanum distinct); it differs from R. mindat by absence of black and white patches on groin (vs. enlarged black and white patches present on groin), by absence of white patches on lateral aspect of thighs (vs. enlarged white patches on lateral aspect of thighs); it differs from R. narpuhensis sp. nov. by presence of brown patch with white crown shaped patch below it on groin (vs. groin yellowish without dark or light patches), and by position of nostril equidistant from eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. nasuta sp. nov. by rounded snout (vs. acute snout), by head being wider than long (vs. head longer than its width), and snout length being equal to inter-upper eyelid width (vs. snout length being greater than inter upper eyelid width); it differs from R. orientalis sp. nov. by scattered tubercles on dorsum (vs. dense spinules on dorsum), darker stripes on dorsum barely visible or absent (vs. concave dorsal stripes distinct); it differs from R. parvulus by absence of inter-upper eyelid bar and stripes on dorsum (vs. bar or triangular mark between upper eyelids and “)(“ mark on dorsum present), tympanum indistinct (vs. tympanum distinct); it differs from R. rezhakhani by absence of concave stripes on dorsum (vs. a “)(“ or “)-(“ mark on dorsum), by presence of single crossband on thigh and tibia (vs. three crossbands on thigh and tibia); it differs from R. shillongensis by absence of stripe or blotch on dorsum (vs. dorsal colour variable, distinct or indistinct “)(“ mark or dark hourglass shaped mark may be present); it differs from R. tytthus nov. comb. by position of nostril equidistant from eye and snout tip (vs. nostril closer to snout tip than eye), by snout length being equal to eye length (vs. snout length longer than eye length), absence of “)(“ marking on dorsum (vs. a “)(“ mark on dorsum); it differs from R. yadongensis by inter-upper eyelid width being slightly less than or equal to eye length (vs. inter-upper eyelid width greater than eye length), absence of triangular mark between upper eyelids (vs. distinct dark triangular marking between upper eyelids), tympanum indistinct (vs. tympanum distinct). Detailed morphological comparison with other congeneric species included in this study is provided in Table 1. Acoustics. The calls of R. monolithus sp. nov. were recorded in Pumdunlong, Manipur on 21 July 2022 at 18:50 hrs at an ambient temperature of 21.6°C. The call description is based on 70 calls from two individuals (WIIADA1634 and WII-ADA1635). The calls are single type, non-pulsatile (Fig. 31) and are emitted in groups (5–13 calls per call group). In each call group, the amplitude peaks after the initial 1–3 calls. The mean call duration is 22.01 ± 16.07 ms (12–29 ms) with a call rise time of 1 ms and call fall time of 18.52 ± 4.62 (11–28 ms). The intercall interval is 164.78 ± 25.14 ms (118–285 ms). The mean dominant frequency is 3470.51 ± 59.77 Hz (3316.1–3531.4 Hz). A detailed comparison of advertisement calls with those of the congeners is presented in Table 2. Phylogenetic relationship and genetic divergence. Raorchestes monolithus sp. nov. is sister to R. shillongensis and R. jadoh with strong nodal support (UFB 100, PP 1.0; Figs 2, 3). The genetic divergence with other congeners included in this study is 3.9–8.6% in the 16S, 11.8–18.2% in the cyt b and 6.5–13.8% in the COI genes (Table S7A–C). Etymology. This species is named after the “monoliths” located in Willong Khullen village in Manipur State, 4 km southwest from the type locality of this species. Suggested common name. Willong-Khullen bush frog. Distribution and natural history. Raorchestes monolithus sp. nov. is known only from its type locality and around Willong Khullen Village in Manipur (Fig. 19B). Calling individuals were recorded between 18:00–20:00 Vertebrate Zoology 75, 2025, 517–625 597 hrs on shrubs and small woody vegetation at perch heights of ~2 m. Calling aggregations were recorded in secondary forests at various degradation state (Fig. 33D). We observed breeding aggregation of Hyla annectans (Jerdon, 1870) in the same habitat in temporary water puddles. Raorchestes khonoma sp. nov. https://zoobank.org/F8DFBFD3-C19D-4B52-AC34BA08D2237356 Figure 38; Tables 1, 2, S12 Holotype. An adult male (WII-ADA897) collected by BB and AD on 8 August 2021 from 2.7 km west of Khonoma village (25.64145°N, 93.99801°E, elevation 2040 m a.s.l.), Kohima District, Nagaland, India. Paratypes. Three adult males (WII-ADA894–896) collected from the same locality as holotype. Diagnosis. Small sized Raorchestes, SVL 16.9–22.0 mm in adult males; head width equal to or slightly wider than length (HL/HW = 0.94–1.0); snout rounded, its length equal to or slightly less than eye length (SL/EL = 0.93–1.0); snout length less than or equal to inter-upper eyelid width (0.94–1.04); nostril equidistant to snout tip and eye; inter-upper eyelid width equal to eye length; internarial distance greater than upper eyelid width (UEW/ IN = 0.75–0.91); dorsal colour pale yellowish brown with golden tinge; slightly darker brown and white patches on groin and inner lateral aspect of thigh; single broad, brown crossbar on thigh and tibia. Description of the holotype. Adult male with vocal sac, SVL 22 mm; head length equals to width; snout rounded in both dorsal and lateral views, its length slightly less than eye length (SL/EL = 0.94) and inter-upper eyelid width (SL/IUE = 0.94); snout sharply sloped anteriorly from internarial region; loreal region slightly concave; canthus rostralis rounded and oblique; interorbital space flat; nostrils oval and obliquely oriented, equidistant between snout tip and eye; eye moderate in size, protruding (EL/HL = 3.4); pineal ocellus absent; tympanum indistinct, rounded; supratympanic fold distinct; internarial distance smaller than inter upper eyelid width (IN/IUE = 0.71) and equal to upper eyelid width; tongue posteriorly broad and bilobed; vomerine teeth absent; choanae rounded; pair of slit like openings on lower jaw; symphysial knob on lower jaw; maxillary teeth present; translucent external subgular vocal sac present. Habitus slender (AG/SVL = 0.5), dorsoventrally flattened; forelimbs slender, forearm length nearly equal to hand length (FAL/HAL = 0.97); third finger longest, relative length of fingers = I<II<IV<III; all digits with rounded discs; largest disc on third and fourth finger, disc width of the finger IV greater than tympanic diameter; circum-marginal groove present on each disc present; palmar tubercles barely visible on left hand; subarticular tubercles large and round, proximal ones on third and fourth finger small and indistinct; subarticular tubercles on finger = 1:1:2:2; on flat granules present on palm, a large fine granular nuptial pad on first fingers. Hindlimbs slender; thigh slightly longer than tibia (TBL/TL = 0.93) and half of snout-vent length (TL/SVL = 0.5); tibia longer than foot length (FOL/TBL = 0.86); relative length of toes = I<II<V<III<IV; toe with rounded disc, as wide as on fingers; circum-marginal groove present on each toe; inner metatarsal tubercle present, outer one absent; subarticular tubercles distinct, round, proximal subarticular tubercles on outer three toes smaller; subarticular tubercles on toes = 1:1:2:3:2; webbing slight, not reaching the second subarticular tubercle of fourth finger. Skin on dorsal aspect of head smooth to shagreen on dorsum; few small tubercles scattered on upper eyelid; few tubercles above supratympanic fold; tubercles dorsolateral aspect of dorsum and on tibia sparsely present; tubercles posterior to angle jaw barely visible; forelimb smooth; gular region, chest granular but not as distinct on abdomen; abdomen granular; flank towards ventrolateral aspect granular; ventral aspect of thigh granular but of tibia smooth. Colouration in life. Dorsally head, back and limbs pale-yellowish brown with golden tinge; a very faint bar on inter-upper eyelid space; faint crossbars on thigh and tibia; ventrally, anterior part of head pale greyish brown, posteriorly pale yellowish brown with dense white mottling on and sparse brown mottling; abdomen whitish with brown mottling, few black irregular spots on anterior part of the abdomen; forelimb ventrally pale yellowish with brown mottling and brown spots on forearms; thighs ventrally pale yellow brown with brown mottling and irregular white spots; large creamy white patches on tibia; large brown patch on groin and slightly smaller white patch on either side of it; another white patch on inner lateral aspect of thigh towards base. Colouration in preservative. Dorsally head and back grey, upper eyelid slightly darker, an indistinct slightly dark bar between upper eyelids; loreal region darker, two indistinct dark streaks on upper jaw radiating from the eye; forelimbs and hindlimbs dorsally greyish brown, slightly darker brown cross bar on forearm, thigh, tibia and tarsus; flank pale greyish brown; on ventral aspect, head cream coloured with brown mottling, dense on anterior part of lower jaw; abdomen cream coloured with small indistinct white spots and brown mottling, irregular small brown patches on abdomen and towards flank; forelimb ventrally with denser brown mottling; hindlimb cream coloured with dense brown mottling, brown crossbars on thigh and tibia visible, pale-white spots on thigh and tibia; no marking on outer lateral aspect of thigh and around vent. Morphological variation. Detailed morphological variations are provided in Table S12. In addition, black spots on the abdomen are absent in the paratypes; a pair of in- Boruah B et al.: Revision of bush frogs from northeast India 598 distinct concave and slightly dark stripes on the dorsum visible on WII-ADA896 in preserved condition. Morphological comparison. Raorchestes khonoma sp. nov. differs from R. andersoni and R. rezakhani by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length); it differs from R. annandalii by snout length being equal to or less than inter-upper eyelid width (vs. snout length greater than inter-upper eyelid width); it differs from R. barakensis sp. nov. by absence of bony projection on humerus (vs. bony projection on humerus present), inter-upper Figure 38. Raorchestes khonoma sp. nov. A–C and F, G holotype (WII-ADA897) in preserved condition. A Dorsal view, B ventral view, C lateral view of head, F ventral view of left hand, G ventral view of left feet. D Dorsal and E ventral view of paratype (WIIADA896) in preserved condition. H–L Holotype in life, H dorsolateral view, I ventral view, J groin, K posterior view of thigh, L granules on abdomen. Scale bar = 10mm. Vertebrate Zoology 75, 2025, 517–625 599 eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length); it differs from R. boulengeri sp. nov. by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length), by absence of spinules on dorsum, few blunt scattered tubercles present (vs. dense spinules on dorsum), and by absence of concave stripes on dorsum, may be barely visible in preserved condition (vs. distinct pair of dark brown concave stripes present on dorsum); it differs from R. cinerascens nov. comb. by presence of a single broad brown crossbar on thigh and tibia (vs. three crossbars on thigh and tibia); it differs from R. dibangensis sp. nov. and R. narpuhensis sp. nov. by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width less than eye length), by nostril being equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. dulongensis by head length being equal to or less than head width (vs. head longer than wide), by nostril being equidistant between eye and snout tip (vs. nostril closer to tip of snout); it differs from R. garo by absence of spinules on dorsum (vs. spinules present on dorsum); it differs from R. hekouensis by presence of nuptial pad only on first finger (vs. nuptial pad present on first and second fingers), presence of few scattered tubercles on dorsum (vs. numerous tubercles on dorsum); it differs from R. hillisi and R. menglaensis by head length being less than or equal to head width (vs. head longer than wide), snout length being equal to or less than eye length (vs. snout length greater than eye length); it differs from R. huanglianshan by snout length being equal to or less than eye length (vs. snout length longer than eye length), nostril being equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. jadoh by larger body size in adult males, SVL 16.9–22.0 mm (vs. SVL 13.6–14.0), and inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length), nostril being equidistant between snout tip and eye (vs. nostril closer to snout tip than eye); it differs from R. kempiae by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length), by snout length being smaller than or equal to inter-upper eyelid width (vs. snout length greater than inter-upper eyelid width); it differs from R. lawngtlaiensis sp. nov. by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width less than eye length), internarial distance being greater than upper eyelid width (vs. internarial distance equal to upper eyelid width); it differs from R. leiktho by larger body size in adult males, SVL 16.9–22.0 mm (vs. SVL 15.7–15.8 mm), nostrils being equidistant between eye and snout tip (vs. nostrils closer to snout tip), presence of scattered tubercles on dorsum (vs. numerous spinules on dorsum), brown and white patches present on groin (vs. a short brown bar present on the groin); it differs from R. longchuanensis by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by nostril being equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); differs from R. mawsynramensis sp. nov. by absence of spinules on head and dorsum, few blunt scattered tubercles present (vs. dense spinules on top of head and dorsum), by absence of concave stripes on dorsum, may be barely visible in preserved condition (vs. distinct pair of dark brown concave stripes present on dorsum); it differs from R. mindat by presence of brown and white patches on groin (vs. enlarged black and white patches present on groin), by presence of scattered tubercles on dorsum (vs. dense spinules on dorsum); it differs from R. nasuta sp. nov. by head length being less than or equal to its width (vs. head longer than wide), rounded snout (vs. snout acute), inter-upper eyelid width being greater than or equal to snout length (vs. snout length greater than inter-upper eyelid width), presence of slightly dark brown and white patch on groin and thigh (vs. bright yellow patches on groin and thigh); it differs from R. orientalis sp. nov. by presence a few blunt scattered tubercles on dorsum (vs. spinules on dorsum), a single broad cross bar visible on thigh and tibia (vs. three or four narrow crossbars on thigh and tibia); it differs from R. parvulus by thigh length being greater than tibia length (vs. thigh length less than or equal to tibia length); it differs from R. shillongensis by absence of “)(“ mark on dorsum (vs. a dark brown “)(“ mark present on dorsum); it differs from R. tytthus nov. comb. by snout length being equal to or less than eye length (vs. snout length longer than eye length); it differs from R. yadongensis by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width greater than eye length), by position of nostrils equidistant between eye and snout tip (vs. nostrils closer to snout tip than eye). Morphologically R. khonoma sp. nov. close to R. monolithus sp. nov. Detailed morphological comparison with other congeneric species is provided in Table 1. Phylogenetic relationship and genetic divergence. Raorchestes khonoma sp. nov. is sister to the clade which includes R. dulongensis, R. hillisi and R. yadongensis with weak support (UFB 71, PP <50; Figs 2, 3). The genetic divergence of R. khonoma sp. nov. with the congeners included in this study are 3.1–6.7% in the 16S, 11.2–17.0% in the cyt b and 7.8–14.3% in the COI genes (Table S7A–C). Etymology. The specific epithet is a toponym derived from the name of the village “Khonoma” in Nagaland State where the type series was collected. Suggested common name. Khonoma bush frog. Distribution and natural history. Raorchestes khonoma sp. nov. is currently known from its type locality Khonoma and Dzuleke village in the Kohima District of Nagaland from an elevation of 2000–2040 m a.s.l. (Fig. 19B). This species has also been recorded from low elevation areas at Khonoma Nature Conservation and Tragopan Sanctuary (KNCTS). Individuals of the species were most commonly found along the subtropical forest margins and hilly terrace croplands (Fig. 33E). Gravid Boruah B et al.: Revision of bush frogs from northeast India 600 females were photographed in June and calling males were recorded from May to September. We observed males calling on shrubs at a perch height of approximatelyone meter above ground level. Many individuals were observed calling from Eupatorium thickets. The area at the type locality was mostly covered by jhum and terrace cultivation. Raorchestes eaglenestensis sp. nov. https://zoobank.org/7035E94D-EA2B-4018-8D95-46EA5DA9309C Figure 39; Tables 1, 2, S12 Holotype. Adult male (WII-ADA1619) collected by BB, KB and DSG on 7 July 2022 near Bompu camp (27.06641°N, 92.40599°E, elevation 1970 m a.s.l.), Eaglenest Wildlife Sanctuary, West Kameng District, Arunachal Pradesh, India. Paratypes. Eight adult males (WII-ADA1612–WIIADA1618, WII-ADA1626) collected from the same locality and same date as the holotype by BB, KB and DSG. Referred material. Three adult males (WII-ADA1556– WII-ADA1558) collected by BB and KB on 30 June 2022 from Glow Bari (27.17112°N, 92.46007°E, elevation 2160 m a.s.l.), approximately 5 km north of Eaglenest Wildlife Sanctuary, West Kameng District, Arunachal Pradesh; two adult females (WII-ADA2513 and WII-ADA2514) and one adult male (WII-ADA2518) collected by KB on 23 August 2022 near Bompu camp (27.07193°N, 92.4005°E, elevation 2000 m a.s.l.), Eaglenest Wildlife Sanctuary, West Kameng District, Arunachal Pradesh. Diagnosis. Small sized Raorchestes, SVL 18.8–23.6 mm in adult males and SVL 21.9–22.8 mm in adult females; head length equal to width or slightly less than width in males (HL/HW = 0.93–1.01) and head longer than wide in females (HL/HW = 1.07); vomerine teeth absent; snout rounded to sub-oval, its length slightly less than or equal to eye length (SL/EL = 0.85–1.0); nuptial pad present on first finger; blunt tubercles on top of head, upper eyelid, dorsum and dorsal surface of limb; pair of olive brown, concave stripes on dorsum; a broad brown crossbar on forearm; three crossbars on thigh and tibia. Description of the holotype. Holotype is well preserved except for an incision on underside of right thigh. Snoutvent length 22.1 mm; head slightly wider than long; depression on dorsal aspect of snout between internasal region and snout tip; snout rounded in dorsal view and nearly acute in lateral view, slightly protruding beyond lower jaw, blunt tubercular projection on snout tip; its length less than eye length (SL/EL = 0.9); canthus rostralis rounded, obliqued; loreal region concave; nostril oval, laterally positioned and obliquely oriented; nostrils equally positioned between eye and snout tip; eye moderate in size, length less than half of head length (EL/HL = 0.41); tympanum round, distinct, nearly one third of the eye length (HTYD/EL = 0.29); supratympanic fold distinct; internasal distance less than inter-upper eyelid width (IN/ IUE = 0.85) and greater than upper eyelid width (UEW/ IN = 0.7); choanae oval; vomerine teeth absent; tongue posteriorly notched and posterior lobe on right side shorter than lobe on left side; pair of slit like openings present on lower jaw; trunk dorso-ventrally flattened, slender, half of snout-vent length (AG/SVL = 0.51). Forelimbs slender, forearm shorter than hand length (FAL/HAL = 0.72); relative length fingers = I<II<IV<III; finger with rounded disc; circum-marginal groove on disc present; disc of the fingers II–IV wider than tympanic diameter; webbing absent; subarticular tubercles rounded and enlarged except the proximal subarticular tubercle on third and fourth finger which smaller and indistinct; subarticular tubercles on fingers I:II:III:IV = 1:1:2:2; palmar tubercles not visible; finger without lateral dermal fringe; fine granular nuptial pad present on base of first finger covering inner lateral and dorsal surface, supernumerary tubercles absent. Hindlimbs slender, thigh length half of the snoutvent length (TL/SVL = 0.5); relative length toes = I<II<III<V<IV; tibia length equal to thigh length and longer than foot length (FOL/TBL = 0.84); toe with rounded disc; disc width equal to those of fingers; circum-marginal groove present; subarticular tubercles rounded, proximal subarticular tubercles on toe III–V smaller and indistinct; indistinct inner metatarsal tubercle present; outer metatarsal tubercle absent; supernumerary tubercles absent; no dermal fringe along toe V; webbing slight, reaching below second subarticular tubercle of fourth toe. Smooth skin on dorsal aspect of snout, upper eyelids and head; three tubercles in a longitudinal straight line on middle of head; indistinct tubercles on upper eyelid; few prominent tubercles on mandibular region behind angle of jaw; tubercles scattered dorsal to supratympanic folds, on dorsum and spreading to flank; tubercles absent on posterior part of dorsum; forelimb and hindlimb smooth dorsally; tubercles on limb not visible as in life condition; throat, chest, ventral aspect of forelimb and tibia smooth; abdomen granular, indistinct; granules on thigh barely visible. Colouration in life. Dorsal surface of head, dorsum and limbs pale reddish brown; upper eyelids pale grey; lateral aspect of head pale-greyish with reddish tinge; iris dark brown, speckled with golden, heavily speckled dorsally; inverted triangular patch on dorsal surface of head covering inter-upper eyelid space and posterior part of head; a broad “X” shaped, olive-brown coloured pattern on dorsum; indistinct cross bar on forearms; similar bars on dorsal surface of hand and outer two fingers; three broad crossbars on thigh and tibia; similar bars on dorsal surface of foot and outer three toes; disc on inner two fingers and inner three toes yellow, rest of the discs reddish with brown mottling; on ventrum, head, abdomen and limbs flesh-coloured with brown mottling; enlarged Vertebrate Zoology 75, 2025, 517–625 601 white blotches on chest and abdomen; lateral side of thigh pale-reddish. Colouration in preservative. Dorsal surface of snout and lateral aspect of head pale brown; slightly dark brown stripe on loreal region; upper eyelids dark grey; large dark brown patch on head; dark brown spots on upper jaw, below eyes to mandibular region; posterior part of head to anterior part of dorsum pale yellowish brown, posteriorly dorsum slightly darker; a “X” shaped dark brown mark on dorsum, its anterior ends starts from posterior corner of upper eyelid, posterior ends broader and directed towards Figure 39. Raorchestes eaglenestensis sp. nov. A Dorsal and B ventral view of holotype (WII-ADA1619) in preserved condition. C Dorsal view of WII-ADA2514 in preserved condition. D–G Holotype in life, D dorsolateral view, E ventral view, F groin, G posterior view of thigh. H WII-ADA1556 in life; I paratype (WII-ADA1615) in life; J, K two uncollected males from Bompu, Eaglenest Wildlife Sanctuary. Scale bar = 10mm. Boruah B et al.: Revision of bush frogs from northeast India 602 groin; forelimbs pale yellowish brown, a broad brown cross bar on forearm; irregular sized, brown patches on top of hands and two outer fingers; hindlimb pale yellowish brown; three broad crossbars on each thigh and tibia; similar bars on tarsus and foot and outer three toes; an enlarged dark brown patch on vent area; throat, chest, abdomen, ventral aspect forelimb and hindlimb pale cream coloured with brown mottling. Sexual dimorphism and morphological variation. In males head length equals to width or slightly smaller than width vs. head longer than head width in female; a subgular vocal sac present in males; a pair of internal vocal sac openings present on lower jaw and a nuptial pad present in males. Snout shape varies among the individuals from rounded to sub-oval; in some individuals, a white bar on head connecting the upper eyelids was observed; irregular shaped and sized yellow spots present on head, back and limbs present in some individuals. Morphometric variations are provided in Table S12. Morphological comparison. Raorchestes eaglenestensis sp. nov. differs from R. annandalii by snout length being smaller than or equal to eye length (vs. snout length greater than or equal to eye length); it differs from R. bara kensis sp. nov. by absence of extra bone on humerus (vs. an extra bone present on humerus); it differs from R. boulengeri sp. nov., R. mawsynramensis sp. nov., and R. orientalis sp. nov. by presence of distinct tubercles on dorsum (vs. dense spinules on dorsum); it differs from R. cinerascens nov. comb. by absence of enlarged dark and light patches on groin (vs. spot partially encircled by yellow tinge on groin); it differs from R. dibangensis sp. nov. by presence of distinct bunt tubercles on dorsum (vs. dense spinules on dorsum), presence of three broad crossbars on thigh and tibia (vs. two indistinct crossbars on thigh and tibia); it differs from R. dulongensis by presence of nuptial pad on first finger (vs. nuptial pad absent); it differs from R. garo by absence of dark brown patches on groin and thigh (vs. present), dorsum with blunt tubercles (vs. dorsum with spinules); it differs from R. hekouensis, R. hillisi and R. malipoensis by larger body size, SVL 18.8–23.6 mm in adult males (vs. 16.1–17.5 mm in R. hekouensis, 15.9–17.7 mm in R. hillisi and 14.6–17.7 mm in R. malipoensis); it differs from R. huanglianshan, R. menglaensis, and R. tytthus nov. comb. by snout length being equal to or less than eye length (vs. snout length longer than eye length); it differs from R. jadoh by larger body size in adult males, SVL 18.8–23.6 mm (vs. SVL 13.6–14.0 mm), and by inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length); it differs from R. khonoma sp. nov. by presence of three crossbars on thigh and tibia (vs. single crossbar on thigh and tibia), presence of distinct “X” mark or concave stripes on dorsum (vs. stripes on dorsum barely visible), presence of tubercles pronounced on head and dorsum (vs. tubercles on head and dorsum comparatively small and more sparsely distributed), and absence of brown and white patch on groin (vs. brown and white patches on groin present); it differs from R. lawngtlaiensis sp. nov. by internarial distance being greater than upper eyelid width (vs. internarial distance equal to upper eyelid width); it differs from R. leiktho by larger body size in adult males, SVL 18.8–23.6 mm (vs. SVL 15.7–15.8 mm); it differs from R. longchuanensis, R. yadongensis by inter upper eyelid width being equal to eye length (vs. inter upper eyelid width greater than eye length); it differs from R. menglaensis Figure 40. Comparative spectrograms and oscillograms illustrating representative calls of two new species of Raorchestes. A, B Oscillograms, C spectrogram, D power spectrum. The call marked with an arrow on top in A is expanded in B. Vertebrate Zoology 75, 2025, 517–625 603 by snout length being equal to or smaller than eye length (vs. snout length longer than eye length); it differs from R. mindat by absence of black or white patches on groin (vs. enlarged black and white patches present on groin), absence of white patches on the lateral aspect of thigh (vs. enlarged white patches on lateral aspect of thigh); it differs from R. monolithus sp. nov. by the distinct “X” mark or concave stripes on dorsum (vs. stripes on dorsum barely visible), tubercles pronounced on head and dorsum (vs. tubercles on head and dorsum comparatively small and more sparsely distributed), and absence of brown and white patch on groin (vs. light brown and white patches on groin present); it differs from R. nasuta sp. nov. by rounded or sub-oval shaped snout (vs. snout acute); it differs from R. narpuhensis sp. nov. by presence of three crossbars on thigh and tibia (vs. single cross bar on thigh and tibia); it differs from R. parvulus by presence of three crossbars on thighs (vs. single cross bar on thigh); it differs from R. rezakhani by absence of dark pattern on groin (vs. a short brown streak present on groin); it differs from R. shillongensis by presence of three broad crossbars on thigh and tibia (vs. single broad crossbar on thigh and tibia). A detailed morphological comparison with its congeneric species is provided in Table 1. Morphological characters of R. eaglenestensis sp. nov. and R. kempiae are similar but they have minor overlap in morphospace (Fig. 6C). Raorchestes kempiae is restricted to south of Brahmaputra Valley while R. eaglenestensis sp. nov. is restricted to north of Brahmaputra Valley. Acoustics. The calls of R. eaglenestensis sp. nov. were recorded in Glowbari, near Eaglenest Wildlife Sanctuary on 30 June 2022 at 20:10 hrs and at an ambient temperature of 21.4°C; in Bompu, Eaglenest Wildlife Sanctuary on 7 July 2022 at 20:00 hrs and at ambient temperature of 21.1°C. The call description is based on 60 calls including two individuals (WII-ADA1558 and WII-ADA1619). The calls are single type, non-pulsatile, emitted in groups (2–4 calls per group) in regular intervals (Fig. 40). The mean call duration is 16.3 ± 1.74 ms (9–20 ms) with call rise time of 1 ms and call fall time of 15.45 ± 1.7 ms (12– 18 ms). The mean inter-call interval is 236.56 ± 8.89 ms (224–270 ms). The mean dominant frequency is 3029.73 ± 61.33 Hz (2971.6–3100.8 Hz). A detailed comparison of advertisement calls with those of congeners is summarised in Table 2. Phylogenetic relationships and genetic divergence. Phylogenetically R. eaglenestensis sp. nov. was recovered as a basal lineage to a large clade containing R. hillisi group, R. kempiae group, R. rezakhani group, and R. garo group in ML analysis with weak support (UFB <50) and in BI analysis it nested with hillisi group with weak support (PP <0.5; Figs 2, 3). The genetic divergence of R. eaglenestensis sp. nov. with the other members of the genus varies between 2.9–8.0% in the 16S, 9.1–19.1% in the cyt b and 7.3–15.4% in the COI genes (Table S7A–C). Etymology. The specific epithet is a toponym derived from the name of the “Eaglenest Wildlife Sanctuary” in the State of Arunachal Pradesh where the type specimens were collected. Suggested common name. Eaglenest Bush frog. Distribution and natural history. Raorchestes eaglenestensis sp. nov. is currently known only from the Eaglenest Wildlife Sanctuary and adjacent areas such as Glow Bari within an elevation range of 1950–2200 m a.s.l. (Figs 25B, 33F) We recorded the individuals on hill slopes along forest trails; in the months of June and July. Calling males were observed on ferns, bamboo and shrubs at a height of 0.5–2 m above ground. Other amphibian species recorded at this locality include Nasutixalus sp., Xenophrys sp. Amolops wangyali Mahony et al., 2022, Amolops sp., Rhacophorus burmanus (Andersson, 1939), Leptobrachium bompu, Duttaphrynus himalayanus (Günther, 1864), Nanorana liebigii (Günther, 1860) and Nanorana sp. Athreya (2006) reported several morphs of unidentified Raorchestes sp. (as Philautus sp.) from Eaglenest Wildlife Sanctuary and suggested that it had at least four different calls. Athreya (2006) did not provide details of the locations and acoustic parameters for comparison. However, some of the photographs of Philautus sp. provided in Athreya (2006) falls within the morphological variation of R. eaglenestensis sp. nov. Raorchestes arunachalensis sp. nov. https://zoobank.org/CE8875FB-F369-4B4E-B5B8-A2EC99C4A6E5 Figure 41; Tables 1, 2, S12 Chresonymy. Ixalus tuberculatus — Annandale (1912): 7, 17 Ixalus annandalei — Annandale (1912): 7, 16 (spelling error) Raorchestes annandalii — Ohler et al. (2018): 282, 286 Holotype. An adult male (WII-ADA1553) collected by BB on 17 June 2022 from Rengging village (28.14136°N, 95.27059°E, elevation 470 m a.s.l.), East Siang District, Arunachal Pradesh, India. Paratype. An adult male (WII-ADA1554) collected along with holotype from the same locality. Referred material. Two adult females (WII-ADA676, WII-ADA677) and four subadult males (WII-ADA491, WII-ADA678, WII-ADA680 and WII-ADA681) collected by BB and AD on 17 October 2019 from Potin (27.34786°N, 93.84970°E, elevation 580 m a.s.l.), Lower Subansiri District, Arunachal Pradesh; one subadult (WII-ADA1712) collected by BB on 29 October 2021 from Balek village (28.06245°N, 95.27216°E, elevation 520 m a.s.l.), East Siang District, Arunachal Pradesh; two adult males (WII-ADA1308 and WII-ADA1327) collected by BB and AD on 12 May 2022 near Deban (27.49662°N, 96.38949°E, elevation 380 m a.s.l.), Nam- Boruah B et al.: Revision of bush frogs from northeast India 604 dapha Tiger Reserve, Arunachal Pradesh; two adult males (WII-ADA1336, WII-ADA1345) collected by BB VJ and AD on 13 May 2022 from Motijheel trail (27.48690°N, 96.33134°E, elevation 660 m a.s.l.), Namdapha Tiger Reserve, Arunachal Pradesh; two adult males (WIIADA1551 and WII-ADA1552) collected by BB on 16 June 2022 from Rottung (28.14113°N, 95.15619°E, elevation 390 m a.s.l.), East Siang District, Arunachal Pradesh; two adult males (WII-ADA1549 and WIIADA1550) collected by BB, KB and DSG on 29 June 2022 near Sessa (27.10079°N, 92.53770°E, elevation 1030 m a.s.l.), West Kameng District, Arunachal Pradesh; four adult males (WII-ADA1704–WII-ADA1707) collected by BB on 8 August 2022 near Mehao nallah (28.15436°N, 95.90596°E, elevation 930 m a.s.l.), Mehao Wildlife Sanctuary, Lower Dibang Valley District, Arunachal Pradesh; one adult male (WII-ADA3203) collected by RNV and SD on 2 May 2023 from Deban (27.49284°N, 96.38569°E, elevation 490 m a.s.l.), Namdapha Tiger Reserve, Arunachal Pradesh; one adult male (WII-ADA3215) collected by RNV and SD on 10 May 2023 from Hornbill (27.53810°N, 96.44037°E, elevation 660 m a.s.l.), Namdapha Tiger Reserve, Arunachal Pradesh; one adult male (WII-ADA3250) collected by AD, RNV, SD and JDG on 25 May 2023 from 70 mile (27.38734°N, 96.78273°E, elevation 870 m a.s.l.), Namdapha Tiger Reserve, Arunachal Pradesh; one adult male (WII-ADA3265) collected by AD, RNV, SD and JDG on 29 May 2023 from Kamala Valley (27.46148°N, 96.42758°E, elevation 650 m a.s.l.), Namdapha Tiger Reserve, Arunachal Pradesh; one subadult (WII-ADA2537) collected by KB on 27 August 2022 from Sessni (27.04747°N, 92.41797°E, elevation 1260 m a.s.l.), West Kameng District, Arunachal Pradesh; one subadult (WIIADA2548) collected by KB on 28 August 2022 from Khellong (27.01314°N, 92.41408°E, 800 m a.s.l.), West Kameng District, Arunachal Pradesh. Diagnosis. A medium sized Raorchestes, SVL 19.6–26.3 mm in adult males and SVL 22.3–27.7 mm in adult females; vomerine teeth absent; snout rounded to subovate in dorsal view; nostril closer to snout tip than eye; inter-upper eyelid width less than eye length; nuptial pad present on first finger in males; numerous tubercles on head, dorsum and limb intermixed with spinules; prominent bluntly conical tubercles on upper eyelid; a broad dark brown “X” marking on dorsum extending to groin; broad dark brown crossbars on forelimb and hindlimb. Description of the holotype. Holotype well preserved except for an incision on underside of right thigh. Medium sized Raorchestes, adult male with vocal sac, 24.8 mm in SVL; head length nearly equal to width (HL/HW = 0.97); snout sub-oval in dorsal view, truncated in lateral view, slightly protruding beyond lower jaw in ventral view; snout slightly depressed dorsally at internarial region; snout length less than eye length (SL/EL = 0.81); canthus rostralis distinct, obliqued; loreal region slightly concave; narial region protruding; nostril oval, laterally positioned and obliquely oriented; nostril equidistant between eye and snout tip; internarial distance less than inter-upper eyelid width (IN/IUE = 0.85) and equal to upper eyelid width; eye moderate in size, less than half of head length (EL/HL = 0.45); tympanum distinct, rounded less than one fourth of eye length; supratympanic fold distinct; vomerine teeth absent; choanae rounded; tongue posteriorly notched; trunk dorso-ventrally flattened, its length nearly half of snout-vent length (AG/SVL = 0.49). Forelimbs slender, forearm length nearly equal to hand length (FAL/HAL = 0.94); relative length of fingers = FI<FII<FIV<FIII; fingers with rounded disc; disc on fourth finger widest and wider than tympanic diameter (HTYD/FIVD = 0.63); circum-marginal groove present on discs; palmar tubercles indistinct; subarticular tubercles distinct and rounded, proximal subarticular tubercle on third and fourth fingers smaller than distal ones; enlarged finely granular nuptial pad present on first finger; webbing between fingers absent. Hindlimbs slender, thigh slightly longer than tibia (TBL/TL = 0.96) and more than half of the snoutvent length (TL/SVL = 0.54); relative length of toes = TI<TII<TIII<TV<TIV; each toe with rounded disc; disc as wide as finger disc; circum-marginal groove present on each disc; elongated metatarsal tubercle present; outer metatarsal tubercle absent; webbing moderate, reaching second subarticular tubercle of fourth toe. Skin on dorsal aspect of snout and anterior part of head smooth with scattered tubercles; prominent tubercles on upper eyelid; posterior part of the head with dense spinules intermixed with blunt slightly large tubercles; scattered tubercles below loreal region and few prominent tubercles on mandibular region; numerous spinules on dorsum and flank; blunt tubercles scattered among spinules on flank; forelimbs smooth dorsally; hindlimbs smooth dorsally with scattered blunt tubercles; on ventral aspect of throat and chest smooth; abdomen and thigh granular; tibia smooth; tubercles on ventro-lateral aspect of tarsus and forearm. Colouration in life. Dorsal aspect of head, dorsum, limbs greyish brown; indistinct light bar with darker edge present on inter-upper eyelid space a broad dark brown “X” mark on dorsum, posterior ends of this marking extending to groin where it is darker; dark brown stripe along supratympanic fold covering tympanum; broad dark stripe on upper jaw ventral to eye; narial region dark brown; a broad dark brown band on forearm, one on base of the hand and one on each third and fourth finger; three broad dark brown crossbars on thigh and tibia; one similar bar on each tarsus and base of foot; irregular dark brown patches on top of foot and toes; dark brown patches on lateral aspect of thigh; enlarged dark brown patch around vent; on ventral aspect of lower jaw, chest, abdomen and limbs whitish; brown mottling along lower jaw; pale yellowish patches on gular area and base of lower arm. Colouration in preservative. Dorsal aspect of head and dorsum brown; upper eyelid dark grey; markings on head, dorsum and limbs visible as in life; forearm, thigh, and tibia paler than dorsum; hand, tarsus, and foot pale cream Vertebrate Zoology 75, 2025, 517–625 605 Figure 41. Raorchestes arunachalensis sp. nov. A–C Holotype (WII-ADA1553) in preserved condition, A dorsal view, B ventral view, C lateral view of head. D–G WII-ADA3203 in life from Namdapha TR, D lateral view, E ventral view, F groin, G posterior view of thigh. H Dorsolateral and I ventral view of WII-ADA678 in life from Potin. J Dorsolateral view of holotype in life. K Paratype (WII-ADA1554) in life. L Dorsolateral view of WII-ADA1549 from Sessa in life. M Dorsolateral view of WII-ADA1705 from Mehao WLS in life. Inset image showing dense tubercles on dorsum in A, distinct blunt tubercles in D, granular skin on abdomen in I. Scale bar = 10 mm. Boruah B et al.: Revision of bush frogs from northeast India 612 shape, oblique and laterally positioned, equidistant from snout tip and eyes; internarial distance smaller than inter-upper eyelid width (IN/IUE = 0.79) and greater than upper eyelid width (UEW/IN = 0.84); inter upper eyelid space slightly convex; canthus rostralis smooth, slightly oblique; loreal region concave; tympanum round, indistinct, less than one third of eye length (HTYD/EL = 0.28); eye moderate in size, less than half of head length (EL/ HL = 0.41). Forelimbs slender, forearm length equal to hand length, nearly one third of snout-vent length (FAL/SVL = 0.27); third finger longest, relative length of fingers = I<II<IV<III; fingers with rounded disc; circum-marginal groove present on each disc; disc on third finger widest and greater than the tympanic diameter (HTYD/FID = 0.78); webbing absent between fingers; subarticular tubercles distinct, proximal one on finger III and IV smaller in size than that of upper one; supernumerary tubercles absent; palmar tubercles indistinct. Hindlimbs slender; thigh longer than tibia (TBL/TL = 0.94) and foot (FOL/TL = 0.8); tibia longer than foot (FOL/TBL = 0.85); fourth toe longest, relative length of toes = I<II<III<V<IV, toes with rounded disc; circum-marginal groove present on each disc; disc on fourth toe wider than tympanic diameter and slightly smaller than that of finger III; subarticular tubercles distinct, rounded, proximal one on toe IV very small; supernumerary tubercles absent; inner metatarsal tubercle present, outer metatarsal tubercle absent. Skin on dorsal aspect of head and dorsum smooth; distinct and bluntly conical tubercles on upper eyelid, posterior part of head, posterior to upper eyelid and anterior part of dorsum; lateral aspect of head smooth, few rounded tubercles behind angle of jaw; supratympanic folds distinct; dorsum with dense spinules, spreading towards flank; forelimbs and hindlimbs smooth with indistinct tubercular projections; on ventrum, head smooth, abdomen, ventral aspect of lower arm, and thigh distinctly granular; numerous flat granules on palm and ventral aspect of foot. Colouration in life. Dorsally head, dorsum and limb dark brown, flank slightly paler; enlarged black patch between two white patches present on groin, covering posterior half of the flank; similar black and white patches of irregular size and shape present on lateral and ventral aspects of thigh, tibia, and lateral aspect of tarsus; one broad black or dark brown crossbar present on dorsal side of each forearm, thigh and tibia; irregular small pale bluish white spots on upper jaw present; ventrally dark brown; small irregular pale-bluish white spots present on gular region, forearm and hind arm, chest, abdomen and ventral side of tarsus; digital disc yellowish on dorsal aspect. Colouration in preservative. Dorsal aspect of head and dorsum similar to that of life colouration; dorsal aspect of limbs slightly paler brown than in life; ventral aspect pale brown, all white and black markings visible as when it was alive. Morphological variation. Details of morphometric variations are provided in Table S12. Shape and size of the black and white patches on groin and hindlimbs varies among individuals; intensity of the small white spots on the ventral aspect of body and on chin varies among individuals of this species. Phylogenetic relationship. Raorchestes mindat is sister to a group containing R. huanglianshan and R. menglaensis with weak support in ML analysis (Fig. 2). In BI analysis, R. mindat recovered as a sister to R. annandalii with weak support (Fig. 3). The genetic divergence of R. mindat with its congeners included in this study are 2.4–7.4% in the 16S, 11.7–17.7% in the cyt b genes (Table S7A–B). Distribution and natural history. Raorchestes mindat was known only from the type locality, between Hline Thoat village and Gyin Dwe village, Ovatmataung National Park of Mindat District, Myanmar. The present study reports this species from India for the first time (Fig. 19B) and it extends the northeast distribution boundary of the species by 548 km from the type locality in Myanmar. We recorded calling males in a degraded agricultural farm on the edge of Fakim Wildlife Sanctuary (Fig. 44A). Calling individuals were found on the hill slopes of an abandoned jhum field between 18:00–19:00 hrs on leaves of EupaFigure 44. Habitats of Raorchestes mindat and R. annandalii A Landscape view of the hills at Fakim WLS and B landscape view at Darjeeling. Vertebrate Zoology 75, 2025, 517–625 613 torium sp., one metre above ground. The area was mostly covered in maize and soybean as well as invasive plants such as Eupatorium sp. and Parthenium sp., on a slope with an incline of approximately 60 degrees. Raorchestes annandalii (Boulenger, 1906) Figures 45, 46; Tables 1, 2, S12 Chresonymy. Ixalus annandalii Boulenger, 1906: 385. Ixalus annandalei — Annandale (1908): 305; incorrect spelling. Rhacophorus (Philautus) annandalii — Ahl (1931): 71. Philautus annandalii — Bourret (1942): 451; Gorham (1974): 166; Sarkar et al. (1992): 90; Dutta (1997): 74; Ahmed et al. (2009): 15, 147. Philautus (Philautus) annandalii — Bossuyt and Dubois (2001): 38. Pseudophilautus annandalii — Li et al. (2009): 519. Raorchestes annandalii — Subba et al. (2017): 4, 11; Frost (2025). Comments on taxonomic status. Boulenger (1906) described Raorchestes annandalii from Kurseong, Darjeeling (= Darjiling), West Bengal, India. Bossuyt and Dubois (2001) redescribed the lectotype (BMNH 1947.2.26.58; female). We re-examined the lectotype at NHM, London and we collected topotypes from Darjeeling. We found the following exception in our collected specimens against the lectotype description by Bossuyt and Dubois (2001): 1) head longer than wide (vs. head length equal to width), snout length equal to eye length (vs. snout length greater than or equal to eye length); tibia longer than thigh (vs. tibia shorter than or equal to thigh). Based on new information, we provide a revised diagnosis and expanded description of this species. Material examined. Lectotype (BMNH 1947.2.26.58; Fig. 45) collected by N. Annandale from Kurseong, Darjeeling (= Darjiling), West Bengal. Newly collected material. Four adult males (WIIADA521, WII-ADA537, WII-ADA548, WII-ADA551) and three adult females (WII-ADA520, WII-ADA530 and WII-ADA533) collected by NGP on 23 April 2018 from Ravangla (27.2879°N, 88.34717°E, elevation 1780 m a.s.l.), Namchi District, Sikkim; one adult male (WIIADA2721) and two adult females (WII-ADA2716 and WII-ADA2722) collected by NGP on 8 August 2022 near Rock Garden waterfall (27.02778°N, 88.22889°E, elevation 1500 m a.s.l.), Darjeeling District, West Bengal. Diagnosis. A small sized Raorchestes (Fig. 46), SVL 17.3–19.6 mm in adult males and SVL 18.9–21.6 mm in adult females; head length equal to head length; vomerine teeth absent; snout rounded to sub ovoid in dorsal view; snout slightly longer than eye length or equal to eye length (EL/SL = 0.82–1.03); snout length greater than or equal to inter-upper eyelid width (SL/IUE = 0.97–1.23); snout length greater than or equal to eye length (SL/EL = 0.96–1.15); nostrils equidistant between eye and snout tip or closer to eye than snout tip; nuptial pad present on first finger in males; dorsal skin on head and dorsum smooth or shagreened; scattered tubercles towards dorsum and flank; dark brown band on inter-upper eyelid space; a pair of concave dark brown stripes on dorsum; brown mottling and white flecks on ventrum. Description of a newly collected material (WIIADA2721). An adult male, small size, SVL 17.3 mm; head as long as wide (HL/HW = 0.98); snout rounded in dorsal view, protruding beyond lower jaw in lateral and ventral views; snout length slightly greater than eye length (EL/SL = 0.92); canthus rostralis rounded, oblique; loreal concave; narial region protruding; internarial distance slightly less than inter upper eyelid width (IN/IUE = 0.91) and greater than upper eyelid width (UEW/IN = 0.75); inter-upper eyelid space slightly convex; nostril oval, laterally positioned and obliquely oriented, equidistant between eye and snout tip; eye in moderate size, less than half of head length (EL/HL = 0.4), slightly greater than inter upper eyelid width (IUE/EL = 0.92); tympanum barely visible, rounded, one fourth of eye length (HTYD/ EL = 0.25); supratympanic fold distinct; vomerine teeth absent; choanae round; tongue posteriorly wide and medially notched, posterior two lobes widely separated; pair of internal vocal sac opening on lower jaw; habitus dorso-ventrally flattened, length more than half of snout-vent length (AG/SVL = 0.52). Forelimbs slender; hand longer than forearm (FAL/ HAL = 0.83); relative length fingers = I<II<IV<III; fingers with rounded disc; disc on third finger slightly wider than tympanic diameter (HTYD/FIIID = 0.75); circum-marginal groove present on each disc; subarticular tubercles distinct and rounded except the proximal subarticular tubercles on third and fourth finger which small and indistinct; palmar tubercles indistinct; webbing on fingers absent; a fine granular nuptial pad on first finger. Hindlimbs slender; thigh longer than tibia (TBL/TL = 0.94) and less than half of snout-vent length (TL/SVL = 0.48); relative length toes = I<II<III<V<IV; rounded disc on toe; disc width equal to that of fingers; subarticular tubercles distinct, rounded except the lower subarticular tubercles on toe III–V which are small and indistinct; indistinct inner metatarsal tubercle present and outer one absent; webbing slight, reaching second subarticular tubercle on fourth toe. Snout and dorsal aspect of head smooth; an indistinct longitudinal ridge on middle of head; lateral aspect of head smooth, a tubercle present on mandibular region; dorsum smooth; flank granular towards ventrolateral aspect, indistinct; forelimbs and hindlimbs smooth on top; on ventrum, throat smooth; posteriorly gular skin granular; chest, and abdomen granular; granules on ventral aspect of thigh indistinct; tibia smooth on ventral aspect. Colouration in life. Head, dorsum and limbs brown on dorsal aspect; anterior part of head to interorbital space slightly paler than posterior part of head and dorsum; loreal region slightly darker; indistinct dark brown patch ventral to eye; a dark-brown stripe below the supratym- Boruah B et al.: Revision of bush frogs from northeast India 614 panic fold; dark brown concave bar on inter-upper eyelid space and dark brown patch posterior to it; pair of concave dark brown stripes on dorsum, starting behind upper eyelid and posterior ends directing towards groin; a broad dark brown crossbar on forearm; similar band on each thigh, tibia, and tarsus; disc on finger and toe yellow; groin, lateral aspect of thigh, inner lateral side of tibia and tarsus reddish-brown; dark brown patch around vent; brown marbling and irregular white flecks on ventral side of head, abdomen and limbs. Sexual dimorphism and morphological variation. Males have a pair of internal vocal sac openings on lower jaw; external subgular vocal sac, and nuptial pad on first finger. Dorsal concave stripes and cross bars may be indistinct in some individuals of this species; tubercle towards flank may be completely absent; Detailed morphometric variations are given in Table S12. Morphological comparison. Raorchestes annandalii diff er from R. andersoni, R. dulongensis, R. hillisi, R. huan gli anshan, R. menglaensis, and R. tytthus nov. comb. by position of nostril equidistant between eye and snout tip or closer to eye than snout tip (vs. nostril closer to snout tip than eye); it differs from R. cinerascens nov. comb. by snout length being greater than or equal to eye length (vs. snout length smaller than eye length); it differs from R. dulongensis by nostril being equidistant between eye and snout tip or closer to eye than snout tip (vs. nostril closer to snout tip than eye); it differs from R. hekouensis by presence of nuptial pad only on first finger (vs. nuptial pad present on first and second fingers); it differs from R. hillisi and R. huanglianshan by nostril being equidistant between eye and snout tip or closer to eye than snout tip (vs. nostril closer to snout tip than eye); it differs from R. jadoh by larger body size in adult males, SVL 17.3–19.6 mm (vs. 13.6–14.0 mm); it further differs from R. jadoh and R. jakoid by head length being greater than or equal to head width (vs. head wider than long), and thigh length being greater than or equal to tibia length (vs. thigh length less than tibia length); it differs from R. leiktho by larger body size in adult males, SVL 17.3–19.6 mm (vs. SVL 15.7–15.8 mm); it differs from R. longchuanensis by inter upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by absence of black patches on groin and inner lateral aspect of thigh (vs. black patches present on groin and inner lateral side of thigh); Figure 45. Raorchestes annandalii (lectotype; BMNH 1947.2.26.58). A Dorsal and B ventral view, C ventral aspect of hand, D ventral aspect of foot, E granular skin on abdomen. scale bar = 10 mm. Vertebrate Zoology 75, 2025, 517–625 615 it differs R. menglaensis by nostril being equidistant between eye and snout tip or closer to eye than snout tip (vs. nostril closer to snout tip than eye); it differs from R. mindat by the absence of black or white patches on groin (vs. enlarged black and white patches present on groin), by absence of white patches on the lateral side of thigh (vs. enlarged white patches on the lateral side of thigh); it differs from R. parvulus absence of dark brown and whitish blotch on groin (vs. dark brown marbling enclosing a whitish blotch present on groin); it differs from R. rezakhani by absence of dark or light pattern on the groin (vs. a short brown streak present on groin), and by snout length being greater than inter-upper eyelid width (vs. snout length less than or equal to inter upper eyelid width); it differs from R. tytthus nov. comb. by position nostril equidistant between eye and snout tip or closer to eye than snout tip (vs. nostrils closer to snout tip than eye); it differs from R. yadongensis by inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length). Morphological comparisons of R. annandalii with newly described species in this study are provided in the morphological comparison section of each respective species and Table 1. Phylogenetic relationship and genetic divergence. Phylogenetically R. annandalii recovered as basal lineage to three species including R. arunachalensis sp. nov., R. magnus sp. nov. and R. longchuanensis in ML analysis with weak support (Fig. 2). In BI analysis, it is sister to R. mindat with weak support (Fig. 3). The genetic divergence with its congeners included in this study are 3.8–8.2% in the 16S, 13.7–19.7% in the cyt b and 10.0–16.8% in the COI genes (Table S7A–C). Distribution and natural history. Sarkar et al. (1992) reported this species from Kalimpong, Goomti, Mahanadi, Ghum Bhanjan in Northern West Bengal; Subba et al. (2017) reported it from Sikkim; Srestha (2001), Anders (2002), Khatiwada et al. (2021) and Shah and Tiwari (2004) reported it from Nepal. Calling aggregations were observed on shrubs after the dusk during April–July (Fig. 44B). Remarks. Annandale (1912) reported this species from Mangaldai, Assam; Chanda (1992, 1994) reported this species from Goalpara in Assam and Namdapha in Arunachal Pradesh followed by Sarkar and Ray (2006). Ao et al. (2003) reported this species from Nagaland. However, our sampling across the region shows that R. annandalii is restricted to Sikkim (Ravangla), Darjeeling (Rock Garden Waterfall) and eastern Nepal. Furthermore, the present study suggests that the previous records of this Figure 46. Newly collected material of R. annandalii. A Dorsolateral and B ventral view of topotype (WII-ADA2721) in life (inset image showing granular skin on abdomen). C WII-ADA534 in life. D–G WII-ADA520, D dorsal view immediately after euthanization (inset image showing fine granular skin on dorsum), E dorsal view, F lateral view of head, G ventral view. Scale bar = 10 mm. Photos A–D by Naitik G. Patel. Boruah B et al.: Revision of bush frogs from northeast India 616 species from Assam (Annandale 1912), Nagaland (Ao et al. 2003) and Arunachal Pradesh (Sarkar and Ray 2006; Mathew and Sen 2010) are erroneous. Wangyal et al. (2020) reported this species from Bhutan, which requires further verification to confirm the identity of this species. Discussion The description of thirteen new species and one new record (R. mindat), as well as the revision of the taxonomy of previously described species, has increased the total number of species in the genus Raorchestes from northeast India to 21. In this revision we resolved the taxonomic identity and phylogenetic status of eight historically known species from the region (R. garo, R. kempiae, “R. asakgrensis”, “R. manipurensis”, “R. namdaphaensis”, and “R. sahai”, Liurana kempii nov. comb., and Nasutixalus microdiscus nov. comb.). The current generic placement of P. dubius still remains unresolved and requires further study. A few studies involving large scale regional sampling have been conducted in the Western Ghats and in northeast India (Biju and Bossuyt 2009; Biju et al. 2011; Biju et al. 2014a, 2014b; Vijayakumar et al. 2014; Garg et al. 2021; Kamei et al. 2013; Mahony et al. 2018). However, this is the first study of its kind to include the genus Raorchestes from the sub-Himalayan region which was previously the subject of anecdotal studies by Pillai and Chanda (1979), Chanda (1992, 1994), Sengupta et al. (2000), Choudhury et al. (2001), Ao et al. (2003); Sarkar and Ray (2006), Sen and Mathew (2008), Mathew and Sen (2010), Sengupta et al. (2010), Sen et al. (2013), Saikia et al. (2016), Ohler et al. (2018), Purkayastha et al. (2020a) or the identity of the species was not determined (Das et al. 2009; Boruah et al. 2018; Purkayastha et al. 2020b). One of the features of the northeast clade of Raorchestes is the overlapping morphological characters of the species in the clade, unlike their congeners in the Western Ghats which are distinctive in their morphological characters, colouration and body size (Biju and Bossuyt 2005; Gururaja et al. 2007; Biju and Bossuyt 2009; Biju et al. 2010; Zachariah et al. 2011; Seshadri et al. 2012; Vijayakumar et al. 2014; Rajkumar et al. 2016; Zachariah et al. 2016; Garg et al. 2021). All the species described in this study are endemic to northeast India. Among the new species, R. boulengeri sp. nov., R. dibangensis sp. nov., R. khonoma sp. nov., R. lawngtlaiensis sp. nov., R. mawsynramensis sp. nov. and R. monolithus sp. nov. are point endemics currently known only from the type localities. Further research may extend the distribution range to neighbouring regions. Our study extended the distribution of R. mindat to India which was recently described from Mindat in Myanmar by Köhler et al. (2025). Of the two widespread species of the region, R. arunachalensis sp. nov. and R. garo, the latter is distributed in the southern part of the Brahmaputra Valley namely Meghalaya, Assam, Mizoram, Manipur, Nagaland and southeastern part of Arunachal Pradesh, Bangladesh to Yunnan, China. The records of R. parvulus from the Garampani-Nambor-Doigurung landscape in Assam (Sengupta et al. 2010) and Bangladesh (Rahman et al. 2022) need further verification. The photograph of R. andersoni (as Theloderma andersoni) from Bangladesh (Ahmad and Mim 2020) seems to be one of the morphs of R. garo. Similarly, the report of R. andersoni from Bhutan (Wangyal and Jamtsho 2022) requires further verification. Recent studies have highlighted the importance of integrative taxonomic approach especially to identify and describe cryptic amphibians (Garg et al. 2018, 2021; Gorin et al. 2024; Vences et al. 2024). Using multiple lines of evidence, we were able to resolve the mistaken taxonomic identities of the R. asakgrensis, R. cangyuanensis, R. manipurensis, R. sahai, and “P. namdaphaensis”. In addition, the present study demonstrates the importance of including the topotypic material in determining the correct identity of cryptic species with overlapping distributions such as in the cases of R. garo and R. kempiae. Re-examination of the type specimens enabled us to transfer Philautus microdiscus and Philautus kempii to Nasutixalus microdiscus nov. comb. and Liurana kempii nov. comb. respectively. Additionally, we recommend generic reallocation of two species of Philautus from Myanmar to the genus Raorchestes (R. cinerascens nov. comb. and R. tytthus nov. comb.). In our multivariate analysis (PCA), R. annandalii, R. garo, R. mindat, and R. shillongensis were distinct in morphospace without overlap with the other members of their respective groups (Fig. 6). Between the phylogenetically sister species such as R. shillongensis and R. monolithus sp. nov., R. mawsynramensis sp. nov. and R. boulengeri sp. nov. there was no overlap in morphospace, while R. arunachalensis sp. nov. and R. magnus sp. nov. have partial overlap. Sample sizes were low for R. dibangensis sp. nov. and R. lawngtlaiensis sp. nov., additional sampling is required to understand the extent of morphological variation of these two species. In addition to this, phylogenetically distantly related species such as R. barakensis sp. nov., R. boulengeri sp. nov., R. eaglenestensis sp. nov., R. kempiae, R. khonoma sp. nov., R. mawsynramensis sp. nov., R. monolithus sp. nov., R. narpuhensis sp. nov., R. nasuta sp. nov. and R. orientalis sp. nov. showed partial overlap in morphospace. The PCA analysis showed that the small-bodied species are morphologically cryptic, while there is clear morphological separation of large-bodied species (R. arunachalensis sp. nov., R. eaglenestensis sp. nov., R. garo, and R. magnus sp. nov. All Raorchestes species found in mainland Asia, except in northeast India, are small-bodied. Therefore, there is a high likelihood of discovering additional cryptic species from previously unsampled locations in mainland Asia. Phylogenetically the northeast Indian lineages of Raorchestes radiated from the “bombayensis group” (Vijayakumar et al. 2016; Garg et al. 2021). The phylogenetic relationships of many of the subclades within this sister clade found in northeast India and the Indochina region remain unresolved with low nodal support (Figs 2, 3). Additional taxon sampling across this region and Vertebrate Zoology 75, 2025, 517–625 617 next-generation sequencing may help resolve these weakly supported nodes. Genetic divergences between sister species found in northeast India are mostly moderate (>2% to <4% in the 16S gene) except for a single species (R. garo) that has high (≥4%) divergence in the 16S gene (Table S7A–C). Additionally, R. nasuta sp. nov. has the lowest (1.5–2%) divergence in the 16S gene (Table S7A–C) from an undescribed lineage found in Tibet and Adi Hills, Arunachal Pradesh (Figs 2, 3). Our results also shows that widespread species such as R. arunachalensis sp. nov. have notable intra-species genetic divergence (0.0–2.2%) in the 16S gene. The genetic divergence among the species of this genus in northeast India is unlike that of Western Ghats. In Western Ghats, Raorchestes species are mostly highly divergent (Vijayakumar et al. 2014). This high divergence can be attributed to: i) the age of the lineages in the Western Ghats being older (ca. 31 million years (my)), and ii) geographical barriers including isolated massifs, and deep valleys such as the Palghat Gap and elevational gradients within the Western Ghats Mountain ranges. Whereas, the lineages in northeast India are recent radiation (ca. 13 my; Vijayakumar et al. 2013) and the terrain in the northeast Indian hills are less variable compared to the Western Ghats. Although the Brahmaputra Valley has been identified as a geographical barrier for certain vertebrate species (Mani 1974; Ripley and Beehler 1990; Pawar et al. 2007; Deepak and Karanth 2018) the role of hill ranges and valleys in the speciation of smaller vertebrates in northeast India remains poorly understood. The diversity of Raorchestes species found in the northeast hills (Sensu Mani 1974) south of the Brahmaputra valley is higher (16 species) compared to those found north of the valley (five species). A similar pattern is observed in the diversity of bent-toed geckos in northeast India (Agarwal et al. 2014; Boruah et al. 2024). In addition to this, the easternmost part of the region more specifically the Namdapha-Kamlang region appears to be a contact zone for the widely distributed species from the north of the valley (R. arunachalensis sp. nov.) and species from south of the valley (R. garo). Altitudinal gradients in the Western Ghats are known to have played a major role in the diversification of bush frogs (Vijayakumar et al. 2016). However, it is poorly understood in northeast India. Based on the samples we collected from 82 localities across northeast India, we found that most of the species in northeast India are distributed across low to mid or high elevations (<100 m to >1500 m), except for two species (R. dibangensis sp. nov. and R. lawngtlaiensis sp. nov.) that are restricted to low elevations (<500 m) and three species (R. eaglenestensis sp. nov., R. mindat and R. khonoma sp. nov.) that are restricted to higher elevations (>1500 m). Additional sampling in this region and biogeographic analyses will either confirm or revise these results and reveal diversification patterns in bush frogs of northeast India and the factors influencing it. Bioacoustic studies have proven to be useful in amphibian taxonomy especially in differentiating cryptic anuran species (Prasad et al. 2020; Garg et al. 2021; Vences et al. 2024; Gorin et al. 2024). The acoustic repertoire of Raorchestes from northeast India can be broadly classified into pulsatile and non-pulsatile calls. Comparatively small-bodied species such as R. mawsynramensis sp. nov. and R. narpuhensis sp. nov. have the highest dominant frequency calls, while large-bodied species such as R. arunachalensis sp. nov., R. garo, and R. eaglenestensis sp. nov. have the lowest dominant frequency calls. Some of the Western Ghats congeners have more than one type of call (1–3 types) and some of them emit both pulsatile and non-pulsatile calls (e.g., R. resplendens Biju et al., 2010; see Garg et al. 2021). However, species from northeast India have a single type of call and emit either pulsatile or non-pulsatile calls. The present study is the first of its kind in northeast India to describe acoustics of 12 species of bush frogs. This will aid future research and acoustic monitoring of anurans in this region. Among the 13 new species of Raorchestes described in this study, seven are from protected areas (PAs) or in the vicinity of PAs namely: R. barakensis sp. nov. (near Barail WLS, Assam), R. dibangensis sp. nov. (near Mehao WLS, Arunachal Pradesh), R. eaglenestensis sp. nov. (Eaglenest WLS, Arunachal Pradesh), R. lawngtlaiensis sp. nov. (Ngengpui WLS, Mizoram), R. nasuta sp. nov. (Namdapha TR, Arunachal Pradesh), R. narpuhensis sp. nov. (Narpuh WLS, Meghalaya) and R. orientalis sp. nov. (Namdapha TR, Arunachal Pradesh). The type localities of R. arunachalensis sp. nov. and R. magnus sp. nov. do not fall within PAs but these species are distributed in PAs (Kamlang TR, Mehao WLS, Mouling NP, Namdapha TR, Arunachal Pradesh). Among the PAs mentioned above, Namdapha TR now has the richest diversity of bush frogs represented by five species. In addition, recently three new amphibian species (Gracixalus patkaiensis, Alcalus fontinalis, Nidirana noadihing Boruah et al., 2023) have been described from Namdapha TR, which represents the northern limit of tropical rainforest distribution (Proctor et al. 1998). Our study reiterates the fact that extensive sampling across multiple physiographic formations is crucial for delineating cryptic diversity that is threatened from anthropogenic activities (Arunachalam et al. 2004). During our fieldsurveys we observed ongoing rapid deforestation in the region due to jhum cultivation, cardamom cultivation, and linear infrastructure and mega dam projects. Protected areas of the northeast Indian region thus are cornerstones for the conservation of endemic amphibian diversity. Acknowledgements We thank the National Geographic Society for the award of National Geographic Explorer Grant (NGS-74044R-20), SERB-DST (CRG/2018/000790) and Meghalaya Biodiversity Board (SBB.84/Research Studies/CAMPA/2021 dated March 2022) for financial support. Fieldwork was made possible with appropriate permissions and logistical support by the State Forest Departments of Arunachal Pradesh, Assam, Meghalaya, Mizoram, Manipur, Nagaland, Tripura, Sikkim and West Bengal (vide letter nos. FWC/G/173/Pt-111/3897-908 dated 9 February, 2016; CWL/GEN/13(95)/11-12/Pt.V/438-40 dated 2 May Boruah B et al.: Revision of bush frogs from northeast India 618 2018; CWL/G/173/2018-19/Pt.VII/1100-07 dated 22 August 2019; WL/FG.31/Technical Committee/2019, dated 18 July, 2019; CWL/ GEN/96(Vol-III)/550 dated 8 July, 2019; B.19060/1/2020-CWLW/112 dated 2 February 2021; CWL/GEN/355/2021/3178 dated 28 September 2021; 866/WL/4R-28/2021 dated 7 April, 2021; No.F.8(163)/ForWL-2020/MoU/1846-51 dated 19 March, 2021; FOR.77/2019/66 dated 27 June, 2022; CWL/173/2018-19/Prt.VII(A)/296-303 dated 20 April 2023). We sincerely acknowledge the support received from officials of Arunachal Pradesh Forest Department namely Sh. Milo Taser, Sh. Aduk Paron, Sh. Tajum Yomcha, Sh. Dhawan Kumar Rawat, Sh. Harshraj Wathore, Sh. Taluk Rime, Sh. Bunty Tao, Sh. B. Darang, Sh. Kabuk Lego, Sh. Taluk Rime, Sh. Rupir Boli, Kashok Solung, Sh. Kamin Dai, Sh. Tashi Mize, Basant Taye, Sh. Mayur Variya, Sh. Aditya Das for their support during field work. We thank Sh. Aochuba (Field director, Intanki NP, Nagaland), Bendang Temsu (Range Officer, Kiphire, Nagaland), Limthure Yimchunger (Nagaland). We thank B. Lalrinmuanpuia (Mizoram) and Parsanga (Ngengpui) for their help. Our sincere thanks to Sh. Arpiyush Sangma (Meghalaya Forest dept.) for valuable support. We thank Gobind Sagar Bhardwaj (Director), Ruchi Badola (Dean) and Sh. Maria Christu Raja D. (Registrar) of Wildlife Institute of India, Dehradun for their constant support. We are grateful to the Director, Zoological Survey of India (ZSI), Kolkata for giving us permission to examine type specimens. We thank Kaushik Deuti, ZSI, Kolkata for his support during type specimen examination. We thank Jeff Streicher for his curatorial support at NHM, London and Mark Wilkinson for checking vomerine teeth for some of the type specimens at NHM. We thank Indraneil Das and Werner Conradie for their valuable inputs on the first draft of this manuscript. We thank Santanu Dey, Naitik G. Patel, Vijayan Jithin, Jason D. Gerard, Samuel Lalronunga, Sourav Dutta, Rajiv N.V., Krishnendu Banerjee, Deb Shankha Goswami, Gaurav Rai Pariyal, Pranoy K. Borah, Vignesh, Mirza G. Ghazi, Shahid Dar, Neelam Dutta, Malsawmdawngliana, Isaac Zosangliana and K. Lalhmangaiha, for field support. We thank A. Madhanraj, Surya Prasad Sharma, Swati Nawani, Surya Narayanan, Kumudani Bala Gautam, Bhim Singh for their help during lab work. BB thanks Shahid Dar, Vineet Rana and Hem Rana for their support during the museum visit in Kolkata. We thank Amirtha Balan and Srabani Bose for their help in statistical analyses. We thank S.K. Dutta, Indraneil Das, Uttam Saikia and Samrat Mondol for their support. 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