New species of Metagonia Simon with directionally asymmetric male and female genitalia (Araneae, Pholcidae)

199 European Journal of Taxonomy 1026: 199–235 https://doi.org/10.5852/ejt.2025.1026.3117 europeanjournaloftaxonomy.eu ISSN 2118-9773 2025 · Huber B.A. & Meng G. This work is licensed under a Creative Commons Attribution License (CC BY 4.0) Received: 28 March 2025 • Accepted: 28 August 2025 • Published: 20 November 2025 Topic editor: Tony Robillard • Section editor: Arnaud Henrard • Desk editor: Pepe Fernández Research article urn:lsid:zoobank.org:pub:2D1E72FA-7236-40F6-9D22-DED6E774317D New species of Metagonia Simon with directionally asymmetric male and female genitalia (Araneae, Pholcidae) Bernhard A. HUBER1,* & Guanliang MENG 1,2  1 Zoological Research Museum Alexander Koenig, LIB, Bonn, Germany. 2 Present address: Institute of Zoology, Chinese Academy of Sciences, China. * Corresponding author: [email protected] 2 Email: [email protected] Abstract. Genital asymmetry is a rare phenomenon in spiders, and directional asymmetry, where all specimens are same-sided, is particularly scarce. In the New World genus Metagonia, only M. mariguitarensis (González-Sponga, 1998) was previously known to be directionally asymmetric. Here we describe three further species in the genus Metagonia that all share directionally asymmetric male and female genitalia: M. embera Huber sp. nov. (Colombia and Panama), M. uca Huber sp. nov. (Colombia), and M. wayuu Huber sp. nov. (Colombia and Venezuela). Metagonia uca is the species with the most extreme asymmetry and also the only species where female asymmetry is not limited to internal structuresbutextendstotheepigynalscape.InterspecificCO1distancesamongthesefourspeciesranged from15.5to20.9%.Intraspecificdistancesmostlyrangedfrom0.0–1.7%, but higher values were found for M. mariguitarensis (up to 9.1%). While the available evidence suggests that directional asymmetry in Metagonia arose only once (in the last common ancestor of the four species above), the origin of the more widespread asymmetry in Metagonia(femaleantisymmetry)islessclear.Webrieflydiscussthe phylogenetic pattern of antisymmetry in Metagonia, concluding that further focused research is necessary to provide the basic data for such an analysis. Keywords.Antisymmetry,Colombia,CO1barcodes,Panama,taxonomy,Venezuela. Huber B.A. & Meng G. 2025. New species of Metagonia Simon with directionally asymmetric male and female genitalia (Araneae, Pholcidae). European Journal of Taxonomy 1026: 199–235. https://doi.org/10.5852/ejt.2025.1026.3117 Introduction While genital asymmetry is a common and widespread phenomenon in some arthropods such as insects, it is exceedingly rare in others, such as spiders (Huber et al. 2007; Huber 2010; Rivera-Quiroz et al. 2020). As a possible explanation, it has been suggested that one-sided mating positions are an option for animals with an unpaired median intromittent organ (such as the insect aedeagus) but not for animals with paired male genitalia (such as the spider pedipalps, or palps) (Huber et al. 2007; Huber 2010). In such a scenario, males in many insect groups may have been under selection to switch from the plesiomorphic European Journal of Taxonomy 1026: 199–235 (2025) 200 and symmetric female-above position to a position that gives the male more control over copulation. In many cases, such a switch will necessarily result in an asymmetric mating position. If the mating position becomes one-sided, this may cause or allow components of the genitalia to become asymmetric too. In spiders, both palps need to be employed to transfer the full amount of sperm, and in many cases also to supply both sides of the paired female internal sperm storage organs. While asymmetric mating positions have also evolved in spiders (e.g., Helversen 1976), the need to use both palps prevented the evolution of one-sided positions, i.e., males that use asymmetric mating positions typically shift from one side to the other within a single copulation. Symmetric and two-sided mating positions in spiders have apparently disfavored the evolution of asymmetric genitalia. Pholcidae C.L. Koch, 1850 are among the few spider families with several cases of genital asymmetry, reflectingatleastfourindependentorigins(Huberet al. 2023). Pholcidae typically mate in a symmetric position, and both palps are usually inserted simultaneously. It has thus been suggested that asymmetry in Pholcidae may have originated via a different route than in insects, i.e., without involving evolutionary changesofmatingposition.Onepossibilitythatwasproposedisthe‘spaceconstrainthypothesis’ (Huber et al. 2007; Huber 2010): exaggerated male genital characters may require females to develop correspondinglycomplexinternalgenitaliathataredifficulttoarrangesymmetricallywithintheavailable space. At some point, further female exaggeration may only be possible if one side is reduced, resulting inasymmetry.Aslongasthesidednessoftheasymmetryisnotfixed,i.e.,femalesareantisymmetric rather than directionally asymmetric, there will be no selection on males to evolve asymmetry. This idea was developed based mainly on studies of the internal female genitalia of Metagonia Simon, 1893 and Mesabolivar yuruani (Huber, 2000) (Huber 2004, 2006). It remains unclear if and to which extent it may also apply to the other Pholcidae cases (Panjange Deeleman-Reinhold & Deeleman, 1986 and Mecolaesthus Simon, 1893) and to other spider families with several independent origins of genital asymmetrysuchasOonopidaeSimon,1890. In the species-rich New World genus Metagonia, female internal genital asymmetry seems to be common, and in most cases it seems to fall in the category of antisymmetry: roughly half of the females are‘right-sided’,theotherhalfare‘left-sided’(Huber1997b;Huber&Villarreal2020).Malesinthose species are symmetric. The only exception previously known was M. mariguitarensis (González-Sponga, 1998), a leaf-dwelling species originally described from Venezuela and later recorded from neighboring South American countries. In this species, all females are same-sided, and this directional asymmetry also extends to the male palps. Right male palps are overall much bigger than left palps. Intriguingly, however, the sperm containers, i.e., the genital bulbs, show the opposite pattern, with bigger left than right bulbs. It has thus been suggested that M. mariguitarensis males use their palps for different purposes: a predominantly stimulating right palp and a predominantly sperm transferring left palp (Huber 2004). Here we describe two new species that appear closely related to M. mariguitarensis judging by numerous specificsimilarities,andonenewspeciesthatmaybetheclosestknownrelativeofthis‘mariguitarensisgroup’,judgingbymoleculardata(Huberet al. 2022). All these species seem to share directionally asymmetric male and female genitalia (sample sizes are partly small), suggesting that this group of species represents a single origin of this rare phenomenon. Material and methods Material examined The taxonomic part of this study is based on the examination of 160 adult specimens (listed in the descriptions below as well as Huber 2004 and Huber & Villarreal 2020), deposited in the following collections: Museo de Entomología de la Universidad del Valle, Cali, Colombia (MUSENUV); HUBER B.A. & MENG G., Asymmetric Metagonia spiders 201 Zoological Research Museum Alexander Koenig, Bonn, Germany (ZFMK); and Zoological Museum of the University of Copenhagen, Denmark (ZMUC). Taxonomy and morphology Taxonomic descriptions follow the style of recent taxonomic work on Metagonia (e.g., Huber & Villarreal 2020; Huber et al. 2022; based on Huber 2000). Measurements were done on a Nikon SMZ18 stereo microscope with an ocular grid and are in mm unless otherwise noted; eye measurements are ±5µm.Genitalbulbdiameterisgivenasthemeanofbulblengthandbulbwidth(asdefinedinHuber 2004:fig.17).PhotoswereeithermadewithaCanonEOS2000DdigitalcameramountedonaNikon SMZ18 stereo microscope or with a Nikon Coolpix 995 digital camera mounted on a Leitz Dialux 20 compound microscope. CombineZP (https://combinezp.software.informer.com/) was used for stacking photos.Drawingsarepartlybasedonphotosthatweretracedonalighttableandfinalizedunderastereo microscope, or they were directly drawn with a Leitz Dialux 20 compound microscope using a drawing tube. Cleared epigyna were stained with chlorazol black. The number of decimals in coordinates gives a rough indication about the accuracy of the locality data: four decimals means that the collecting site is within about 10 m of the indicated spot; three decimals: within ~100 m. The distribution map was generated with ArcMap ver. 10.0 (Environmental Systems Research Institute, Redlands, CA). Species descriptions are sorted by similarity to Metagonia mariguitarensis, the only previously known species of Metagonia with asymmetric male genitalia. Abbreviations ALE = anterior lateral eye(s) ALS = anterior lateral spinneret(s) AME = anterior median eye(s) a.s.l. = above sea level L/d = length/diameter PME = posterior median eye(s) PMS = posterior median spinneret(s) Abbreviationsusedinfiguresonlyareexplainedinthefigurelegends. Molecular data and analyses OftheeleveningroupCO1barcodesusedinthisstudy(Table1),fourwerenewlygeneratedusing Sanger sequencing as described in Huber & Meng (2024) (UH codes in Table 1), seven were taken from the literature (JA23 from Astrin et al. 2006, M codes and BH codes from Huber et al. 2022). As a root, we used Metagonia taruma Huber, 2000 (from Huber et al.2022).DNAextraction,amplification, sequencing, barcode assembly, and alignment followed the same protocols as described in Huber et al. (2024). A neighbor-joining (NJ) tree (Saitou & Nei 1987) and genetic distances among specimens were calculated using the Kimura 2-parameter model (Kimura 1980) in MEGA 11 (Tamura et al. 2021), during which pairwise deletion of gaps in the alignment was applied. The NJ tree was assessed with 5000 bootstrap replications (Felsenstein 1985). European Journal of Taxonomy 1026: 199–235 (2025) 202 Table 1. Geographic origins and GenBank accession numbers of ingroup specimens. Specimens are sorted as in Fig. 23. Previously published sequences are included for the sake of completeness: BH codes and M codes from Huber et al. 2022; JA23 from Astrin et al. 2006. Code Genus Species Vial Country Admin Locality Lat Long CO1 UH542 Metagonia uca sp. nov. Col238 Colombia Quindío Armenia, Universidad del Quindío 4.5537 -75.6608 PV788227 UH254 Metagonia uca sp. nov. Col237 Colombia Quindío N of Circasia, Bosque del Silencio 4.6411 -75.6379 PV788224 UH260 Metagonia embera sp. nov. Col247 Colombia Risaralda near Santa Cecilia 5.3458 -76.1094 PV788225 M025 Metagonia embera sp. nov. Car260 Colombia Chocó JardínBotánicodelPacífico 6.2663 -77.3749 OL870383 UH288 Metagonia wayuu sp. nov. Col290 Colombia La Guajira Tomarrazón 11.0701 -72.9357 PV788226 M092 Metagonia wayuu sp. nov. Ven20-149 Venezuela Falcón near Santa Cruz de La Alegría 10.8795 -68.4949 OL870413 BH45 Metagonia mariguitarensis Ven18-163 Venezuela Bolívar Ciudad Guayana, Parque La Llovizna 8.3130 -62.6724 OL870335 BH118 Metagonia mariguitarensis Ven18-163 Venezuela Bolívar Ciudad Guayana, Parque La Llovizna 8.3130 -62.6724 OL870348 BH46 Metagonia mariguitarensis Ven02/100-43 Venezuela Sucre Marigüitar 10.4390 -63.9080 OL870336 BH117 Metagonia mariguitarensis Ven02/100-43 Venezuela Sucre Marigüitar 10.4390 -63.9080 OL870347 JA23 Metagonia mariguitarensis Ven02/100-43 Venezuela Sucre Marigüitar 10.4390 -63.9080 DQ667887 HUBER B.A. & MENG G., Asymmetric Metagonia spiders 203 Results Taxonomy Class Arachnida Lamarck, 1801 OrderAraneaeClerck,1757 Family Pholcidae C.L. Koch, 1850 Genus Metagonia Simon, 1893 Metagonia mariguitarensis (González-Sponga, 1998) Figs 1A–B, 2A–B, 3–7 Anomalaia mariguitarensisGonzález-Sponga,1998:25,figs21–32(fig.28missing). Metagonia mariguitarensis–Huber2000:67,figs256–263(exceptspecimensfromPeru,figs264–267, seeDistributionbelow);2004:318,figs15–28. — Carvalho et al. 2017: 13. — Huber & Villarreal 2020:179,figs640–643, 1052 (except specimens from Falcón, see Distribution below). — Huber et al. 2022: 678 (molecular data, except specimen M092 Metagonia mariguitarensis Ven20-149, see Metagonia wayuu sp. nov. below). Notes This species has been studied extensively (see synonymy) and we do not have new material. However, it is included here because two very similar species newly described below require an updated diagnosis, and because a few details were missing in previous studies. In addition, some specimens previously assigned tentatively to this species are now considered to belong to other species (see Distribution below). Diagnosis Leaf-dwelling, long-legged pholcid with dark pattern on carapace (Figs 1–2). Easily distinguished from most known congeners (except M. wayuu sp. nov. and M. uca sp. nov.) by strongly asymmetric male palps (Figs 3–4; including asymmetry of femur and tibia), by male chelicerae with pair of strong lateral protrusions (Fig. 5A), and by female external and internal genitalia (Figs 5C, 6–7; epigynum withposteriorsemicircularprocess,or‘scape’;internalgenitaliawithcomplexsystemofpouches, ducts, and folds). Distinguished from both M. wayuu and M. uca by male chelicerae with rounded rather than pointed distal apophyses (Fig. 5A), by main branch of left procursus with distinctive ventral indentation (bold arrow in Fig. 4C), by hair-like process on right procursus (arrow in Fig. 4D), and by less pronounced palpal asymmetry, i.e., absolutely and relatively smaller right palp (e.g., right/left tibia diameter < 2.5 vs > 2.6; see also Fig. 22). Further distinguished from M. uca by different color pattern on carapace (both in males and females; Fig. 2), by smaller size and shorter legs (e.g., male tibia 1 < 5.0 vs > 6.5; female tibia 1 < 4.0 vs > 5.5), and by female external genitalia (epigynal scape without asymmetric groove; compare Fig. 6B with Fig. 16B). Description (amendments; see Huber 2000, 2004) Right procursus with hair-like process on retrolateral side (arrow in Fig. 4D). Prolateral trichobothrium absent on tibia 1, present on other leg tibiae. Female tibia 1 length (N = 50): 3.2–3.8 (mean 3.5). Shape of pore plates slightly variable (Fig. 7B, D). European Journal of Taxonomy 1026: 199–235 (2025) 204 Barcodes Wesequencedfivespecimensfromtwolocalities(geographicdistance:270km)(Table1;Fig.23). Within localities, distances were 0.0%; between localities, distances ranged from 8.4–9.1% (Table 2). Distances to the other three species treated herein ranged from 15.5 to 20.2 %. Fig. 1. Life specimens. A–B. Metagonia mariguitarensis (González-Sponga, 1998), male and female with eggsac from Venezuela, Ciudad Guayana, Parque La Llovizna. C–D. Metagonia wayuu Huber sp. nov., male and female with eggsac from Colombia, La Guajira, Tomarrazón. E–F. Metagonia uca Huber sp. nov., from Colombia, Quindío, Armenia and female from Quindío, Bosque del Silencio. G–H. Metagonia embera Huber sp. nov., males from Colombia, Risaralda, Santa Cecilia. At various scales. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 205 Table 2. CO1K2Pgeneticdistancesamongingroupspecimens.Boldnumbersareintraspecificdistances(N=13,0.0–9.1%,mean4.2%);interspecific distances (N = 42): 15.5–20.9% (mean 18.5%). UH254 UH542 M025 UH260 M092 UH288 BH45 BH118 BH46 JA23 UH254 Metagonia uca Col237 UH542 Metagonia uca Col238 0.002 M025 Metagonia embera Car260 0.205 0.209 UH260 Metagonia embera Col247 0.200 0.205 0.006 M092 Metagonia wayuu Ven20-149 0.192 0.195 0.173 0.172 UH288 Metagonia wayuu Col290 0.200 0.203 0.169 0.167 0.017 BH45 Metagonia mariguitarensis Ven18-163 0.195 0.193 0.190 0.186 0.159 0.164 BH118 Metagonia mariguitarensis Ven18-163 0.195 0.193 0.190 0.186 0.159 0.164 0.000 BH46 Metagonia mariguitarensis Ven02/100-43 0.188 0.191 0.188 0.188 0.155 0.164 0.084 0.084 JA23 Metagonia mariguitarensis Ven02/100-43 0.197 0.202 0.194 0.194 0.176 0.189 0.091 0.091 0.000 BH117 Metagonia mariguitarensis Ven02/100-43 0.188 0.191 0.188 0.188 0.155 0.164 0.084 0.084 0.000 0.000 European Journal of Taxonomy 1026: 199–235 (2025) 206 Distribution Known from several localities in eastern Venezuela (Sucre, Bolívar) and northwestern Brazil (Roraima) (Fig. 24). The females from Falcón listed in Huber & Villarreal (2020) are here assigned to the newly described M. wayuu sp. nov. (see below). Specimens from Peru listed and illustrated in Huber (2000) are considered to represent a distinct, formally undescribed species (or more than one species). Metagonia wayuu Huber sp. nov. urn:lsid:zoobank.org:act:BCE082D1-FE9C-446F-BD02-AA5ACA06CBE2 Figs 1C–D, 2C–D, 8–12 Metagonia mariguitarensis–Huber&Villarreal2020:179(misidentification;specimensfromFalcónonly). — Huber et al. 2022: 678 (molecular data, specimen M092 Metagonia mariguitarensis Ven20-149). Diagnosis Easily distinguished from most known congeners (except M. mariguitarensis and M. uca sp. nov.) by strongly asymmetric male palps (Fig. 8), by male chelicerae with pair of strong lateral protrusions Fig. 2. Male (top) and female (bottom) prosomata, dorsal views, at same scale. A–B. Metagonia mariguitarensis (González-Sponga, 1998), from Venezuela, Sucre, Marigüitar (ZFMK Ar 22011). C–D. Metagonia wayuu Huber sp. nov., paratypes from Colombia, La Guajira, Tomarrazón (ZFMK Ar 24780). E–F. Metagonia uca Huber sp. nov., paratypes from Colombia, Quindío, Armenia (ZFMK Ar 24781, 24782). Scale line = 0.5 mm. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 207 (Fig. 10A), and by female external and internal genitalia (Figs 11–12; epigynum with posterior semicircularprocess,or‘scape’;internalgenitaliawithcomplexsystemofpouches,ducts,andfolds). Distinguished from M. mariguitarensis by male chelicerae with pointed rather than rounded distal apophyses (Fig. 10A), by main branch of left procursus without distinctive ventral indentation (compare Fig. 4C with Fig. 9C), by absence of hair-like process on right procursus (compare Fig. 4D with Fig. 9D), and by stronger palpal asymmetry, i.e., absolutely and relatively bigger right palp (e.g., right/left tibia diameter > 2.6 vs < 2.5; see also Fig. 22). Further distinguished from M. uca by different color pattern on Fig. 3. Metagonia mariguitarensis (González-Sponga, 1998), male from Venezuela, Sucre, Marigüitar (ZFMK Ar 17867). Left and right palps at same scale. A–C. Left palp, prolateral, dorsal, and retrolateral views. D–F. Right palp, retrolateral, dorsal, and prolateral views. Abbreviations: b = genital bulb; e = embolus; fe = femur; hp = hinged process; p = procursus (main branch); ti = tibia. Scale line = 0.5 mm. European Journal of Taxonomy 1026: 199–235 (2025) 214 Description Male (holotype) MeasureMents. Total body length 2.8, carapace width 0.75. Distance PME–PME 170 µm; diameter PME 90 × 110 µm; distance PME–ALE 25 µm; AME absent. Leg 1: 18.7 (5.0 + 0.4 + 4.7 + 7.6 + 1.0), tibia 2: 2.8, tibia 3: 1.8, tibia 4: 2.8; tibia 1 L/d: 59; diameters of leg femora (at half length) 0.10; of leg tibiae 0.08. Fig. 12. Metagonia wayuu Huber sp. nov., cleared female genitalia in ventral (A, C) and dorsal (B, D) views. A–B. From Colombia, La Guajira, Tomarrazón (ZFMK Ar 24780). C–D. From Venezuela, Falcón, Santa Cruz (D–F) (ZFMK Ven20-149). Scale lines = 0.3 mm. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 215 Color (in ethanol). Carapace pale whitish ochre, with median brown mark including ocular area (Fig. 2C), clypeus not darkened; sternum whitish; legs whitish ochre, patellae and tibia-metatarsus joints brown; abdomen whitish, dorsally with few dark marks. B ody .HabitusasinFig.1C.Ocularareaslightlyraised.Carapacewithoutthoracicgroove.Clypeus with sclerotized rim (sclerotized rim narrower than in M. uca sp. nov.; cf. Fig. 15A). Sternum wider than long(0.54/0.46),unmodified.Abdomenapproximatelytwiceaslongaswide,dorso-posteriorlypointed. CheliCerae. As in Fig. 10A–B; with pair of lateral conical processes, pair of distal frontal processes set with~23modified(globular)hairseach,andpairofslightlydivergingapophysesinfrontoffangjoints. PalPs.AsinFig.8;coxaunmodified,apparentlysymmetric;trochanterwithshortroundedventral process, apparently symmetric; all other segments directionally asymmetric, see below; femur with distinct process on prolateral-ventral side; procursus consisting of main branch and ventral hinged process; genital bulb simple, consisting of globular part and embolus. asyMMetry. Right femur rather cylindrical, with cylindrical prolateral-ventral process; left femur smaller, distally strongly widened, and with conical prolateral-ventral process. Right tibia much bigger than left tibia (maximum diameter in lateral view 0.56–0.61 vs 0.21–0.22). Right procursus consisting of strongly sclerotized main branch (distally the sclerite is partly internal, covered by weakly sclerotized semitransparent cuticle) and weakly sclerotized semitransparent ventral hinged process; left procursus much smaller, with slender main branch, with distally widened and heavily sclerotized ventral hinged process. Right genital bulb with small globular part (diameter 0.27–0.29) and long slender embolus; left genital bulb with larger globular part (diameter 0.36–0.38) and with shorter and strongly widened embolus (similar to M. uca sp. nov.; cf. Fig. 15B–C). legs. Without spines, without curved hairs, without sexually dimorphic short vertical hairs; retrolateral trichobothrium of tibia 1 at 9%; prolateral trichobothrium absent on tibia 1; tarsus 1 with ~20 pseudosegments, very indistinct except distally. Variation Males Tibia 1 in three other males: 4.2, 4.2, 4.5. Color pattern on carapace consistent but pattern on abdomen variable, entirely whitish or with black and white marks dorsally. Females In general very similar to male (Fig. 1D) but carapace pattern limited to black lines (Fig. 2D), clypeus unmodified,sternumcolorvariable,insomefemaleswithbrownmarksnearlegcoxaeorentiresternum speckled; abdomen color variable as in males. Tibia 1 in ten females: 3.6–3.9 (mean 3.7). Epigynum (Fig. 11) simple, mostly weakly sclerotized, posteriorly with sclerotized scape, apparently symmetric; internal asymmetric structures visible through cuticle; posterior epigynal plate short and indistinct. Internal genitalia (Figs 10C, 12) with sclerotized receptacle on right side, with complex system of pouches, ducts, and folds (apparently similar to M. mariguitarensis;cf.Huber2004:figs1–2); with pair of oval pore plates (possibly slightly asymmetric, but this might be an artifact of preparation). Barcodes We sequenced two specimens from two localities (geographic distance: 485 km) (Table 1; Fig. 23). The CO1distancewas1.7%(Table2).Distancestotheotherthreespeciestreatedhereinrangedfrom15.5 to 20.3%. European Journal of Taxonomy 1026: 199–235 (2025) 216 Distribution Known from northern Colombia (La Guajira) and northwestern Venezuela (Falcón) (Fig. 24). Natural history At the type locality, the spiders were collected from palm and Heliconia L. leaves in a disturbed forest remnant along a river. The locality was shared with Mesabolivar eberhardi Huber, 2000 and an undescribed species of ChibcheaHuber,2000.InFalcón,thefivefemaleswerecollectedclosetothe forest margin of a well-preserved forest. They shared the locality with two further representatives of Metagonia, M. latigo Huber, 2020 and M. guttata Huber, 2020. The latter species seemed to share the same large dicot plant leaves with M. wayuu sp. nov. (Huber & Villarreal 2020). Metagonia uca Huber sp. nov. urn:lsid:zoobank.org:act:FB512521-5B86-4526-8AEF-0FF99EAAA7C3 Figs 1E–F, 2E–F, 13–16 Diagnosis Easily distinguished from most known congeners (except M. mariguitarensis and M. wayuu sp. nov.) by strongly asymmetric male palps (Fig. 13), by male chelicerae with pair of strong lateral protrusions (Fig. 15D), and by female external and internal genitalia (Figs 15F, 16; epigynum with posterior semicircularprocess,or‘scape’;internalgenitaliawithcomplexsystemofpouches,ducts,andfolds). Distinguished from both M. mariguitarensis and M. wayuu by different color pattern on carapace (both in males and females; Fig. 2), by larger size and longer legs (e.g., male tibia 1 > 6.5 vs < 5.0; female tibia 1 > 5.5 vs < 4.0), and by female genitalia (epigynal scape with asymmetric groove; Fig. 16B). Further distinguished from M. mariguitarensis by male chelicerae with pointed rather than rounded distal apophyses (Fig. 15D), by main branch of left procursus without distinctive ventral indentation (compare Fig. 4C with Fig. 14C), by absence of hair-like process on right procursus (compare Fig. 4D with Fig. 14D), and by stronger palpal asymmetry, i.e., absolutely and relatively bigger right palp (e.g., right/left tibia diameter > 2.6 vs < 2.5; see also Fig. 22). Etymology Thespeciesnamealludestofiddlercrabs(Uca and other genera), where the males have a major claw significantlylargerthantheminorclaw. Type material Holotype COLOMBIA–Quindío•♂;Armenia,UniversidaddelQuindío;4.5537°N,75.6608°W;1500ma.s.l.; 8 Sep. 2022; B.A. Huber and G.A. Rodríguez leg.; MUSENUV Ar 3533. Paratypes COLOMBIA–Quindío•1♂,2♀♀;samecollectiondataasforholotype;MUSENUVAr3534•7♂♂, 9♀♀;samecollectiondataasforholotype;ZFMKAr24781, 24782. Other material examined COLOMBIA–Quindío•3♀♀,1juv.,inpureethanol;samecollectiondataasforholotype;ZFMK Col238(voucherofUH542)•1♀;3kmNofCircasia,ReservaBosquedelSilencio;4.6411°N, 75.6379°W;1850ma.s.l.;7Sep.2022;B.A.HuberandG.A.Rodríguezleg.;ZFMKAr24783•2♀♀, in pure ethanol; same collection data as for preceding; ZFMK Col237 (voucher of UH254). – Risaralda •1♀;LaCelia,VeredaSanEugenio;4.970°N,75.006°W;1600ma.s.l.;25Feb.2010;N.Betancour HUBER B.A. & MENG G., Asymmetric Metagonia spiders 217 leg.;MUSENUV2214•1♀;samecollectiondataasforpreceding;MUSENUV2220•1♂,1♀;same collection data as for preceding; MUSENUV 2226. Description Male (holotype) MeasureMents. Total body length 3.2, carapace width 0.9. Distance PME–PME 250 µm; diameter PME 120 × 130 µm; distance PME–ALE 30 µm; AME absent. Leg 1: 31.5 (7.8 + 0.5 + 7.7 + 14.0 + 1.5), tibia 2: 4.9, tibia 3: 2.8, tibia 4: 4.4; tibia 1 L/d: 86; diameters of leg femora (at half length) 0.10–0.11; of leg tibiae 0.09. Fig. 13. Metagonia uca Huber sp. nov., paratype, ♂, from Colombia, Universidad del Quindío (ZFMK Ar 24781). Left and right palps at same scale. A–C. Left palp, prolateral dorsal, and retrolateral views. D–F.Rightpalp,retrolateral,dorsal,andprolateralviews;notethatrightbulbisartificiallyrotatedaway from resting position (cf. Fig. 8F). Scale line = 1 mm. European Journal of Taxonomy 1026: 199–235 (2025) 218 Color (in ethanol). Carapace anteriorly pale ochre-yellow, posterior half dark brown (Fig. 2E), ocular area with brown pattern, clypeus brown; sternum whitish; legs ochre-yellow, patellae and tibia-metatarsus joints dark brown; abdomen pale ochre-gray, dorsally and laterally with dark and whitish marks. Fig. 14. Metagonia uca Huber sp. nov., paratype, ♂, from Colombia, Universidad del Quindío (ZFMK Ar 24781). Left and right palpal tarsi and procursi at different scales. A–C. Left tarsus and procursus, prolateral, dorsal, and retrolateral views. D–F. Right tarsus and procursus, retrolateral, dorsal, and prolateral views. Scale lines = 0.5 mm. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 219 B ody .HabitusasinFig.1E.Ocularareaslightlyraised.Carapacewithoutthoracicgroove.Clypeus withstronglysclerotizedrim(Fig.15A).Sternumwiderthanlong(0.68/0.56),unmodified.Abdomen approximately twice as long as wide, dorso-posteriorly pointed. CheliCerae. As in Fig. 15D–E; with pair of lateral conical processes, pair of distal frontal processes set with ~12–14modified(globular)hairseach,andpairofdivergingapophysesnearfangjoints. Fig. 15. Metagonia uca Huber sp. nov., paratypes, male and female, from Colombia, Universidad del Quindío (ZFMK Ar 24781, 24782). A. Male ocular area, clypeus, and chelicerae, oblique frontal view. B–C. Right and left genital bulbs, prolateral views, at same scale. D–E. Male chelicerae, frontal and lateral views. F. Cleared female genitalia, dorsal view. Scale lines: A–C, F = 0.5 mm; D–E = 0.3 mm. European Journal of Taxonomy 1026: 199–235 (2025) 220 PalPs.AsinFig.13;coxaunmodified,apparentlysymmetric;allothersegmentsdirectionallyasymmetric, see below; trochanter with short ventral apophysis; femur with distinct process on prolateral-ventral side; procursus consisting of main branch and ventral hinged process; genital bulb simple, consisting of globular part and embolus. Fig. 16. Metagonia ucaHubersp.nov.,paratype,♀,fromColombia,UniversidaddelQuindío(ZFMK Ar 24782). A. Abdomen, ventral view. B–C. Epigynum, ventral and lateral views; arrow in B points at asymmetric groove. D–E. Cleared female genitalia, ventral and dorsal views. Scale lines = 0.5 mm. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 221 asyMMetry. Right trochanter slightly larger than left trochanter. Right femur rather cylindrical, with cylindrical prolateral-ventral process; left femur smaller, distally strongly widened, and with conical prolateral-ventral process. Right tibia much bigger than left tibia (maximum diameter in lateral view: 0.70–0.77 vs 0.25–0.27). Right procursus consisting of strongly sclerotized main branch (distally the sclerite is mostly internal, covered by weakly sclerotized and semitransparent cuticle) and weakly sclerotized semitransparent ventral hinged process; left procursus much smaller, with slender main branch, with distally widened and heavily sclerotized ventral hinged process. Right genital bulb with small globular part (diameter 0.30–0.34) and long slender embolus; left genital bulb with larger globular part (diameter 0.42–0.46) and with shorter and strongly widened embolus (Fig. 15B–C). legs. Without spines, without curved hairs, without sexually dimorphic short vertical hairs; retrolateral trichobothrium of tibia 1 at 8%; prolateral trichobothrium absent on tibia 1; tarsus 1 with ~25 pseudosegments, very indistinct. Variation Males Tibia 1 in ten males: 6.7–7.8 (mean 7.4). Females In general very similar to male (Fig. 1F) but carapace posteriorly with two Y-marks (Fig. 2F), ocular area andclypeusnotdarkened,clypeusunmodified,sternumdarker(eitherdarkbrownwithsmalllightspots or light brown and medially ochre). Tibia 1 in 18 females: 5.7–6.6 (mean 6.2). Epigynum (Fig. 16A–C) simple, mostly weakly sclerotized, posteriorly with sclerotized and slightly asymmetric scape (groove on left side; all females same-sided); internal asymmetric structures visible through cuticle; posterior epigynal plate short and indistinct. Internal genitalia (Figs 15F, 16D–E) with sclerotized receptacle on right side, with complex system of pouches, ducts, and folds (apparently similar to M. mariguitarensis; cf.Huber2004:figs1–2); with pair of elongated pore plates (possibly slightly asymmetric, but this mightbeanartifactofpreparation).OneclearedfemalefromVeredaSanEugenioapparentlyidentical to female from type locality. Barcodes We sequenced two specimens from two localities (geographic distance: 10 km) (Table 1; Fig. 23). The CO1distancewas0.2%(Table2).Distancestotheotherthreespeciestreatedhereinrangedfrom18.8 to 20.9%. Distribution Known from three neighboring localities in Colombia (Fig. 24). Natural history In Armenia, most specimens were collected from palm leaves in the entrance area of the small secondary forest within the university campus; deeper in the forest they seemed to be very rare or absent. They shared the locality with a second (undescribed, symmetric) species of leaf-dwelling Metagonia. In Reserva Bosque del Silencio, the three females were collected on a single small palm tree; no further specimens were found despite focused search. Metagonia embera Huber sp. nov. urn:lsid:zoobank.org:act:1E9D5F43-AB9F-4C3F-981A-341B529C64DC Figs 1G–H, 17–21 M025 Metagonia Car260 – Huber et al. 2022: 678 (molecular data). European Journal of Taxonomy 1026: 199–235 (2025) 222 Diagnosis Easily distinguished from known congeners by male palpal asymmetry largely restricted to procursus (Figs 17–18), i.e., barely involving palp size as in other species with asymmetric males described above.Alsobyroundedmedianprocessonclypeus(Fig.19A),bymalecheliceraewithsmall,modified (globular) hairs arranged in two lateral bands (Fig. 19A), by epigynum without scape (Fig. 20B), and by asymmetric structures in female internal genitalia (Figs 19B, 20D–G; sclerotized receptacle on right side and arched membranous structure on left side). Etymology The species name honors the Emberá, an indigenous people in the Chocó Department of western Colombia and in Panama. Type material Holotype COLOMBIA–Risaralda•♂;nearSantaCecilia;5.3458°N,76.1094°W;450ma.s.l.;9Sep.2022; B.A. Huber and G.A. Rodríguez leg.; on leaves at forest edge; MUSENUV Ar 3535. Paratype COLOMBIA–Risaralda•1♂;samecollectiondataasforholotype;ZFMKAr24784. Other material examined COLOMBIA–Chocó•1♂,1♀,inpureethanol;JardinBotánicodelPacífico,“trailtoMiradorafter streamcrossings”;6.266°N,77.375°W;16Jan.2014;CarBioteamleg.;ZFMKCar260(voucherof M025)•1juv.,assignedtentatively,inpureethanol;JardinBotánicodelPacífico,CeibaLoopTrail; 6.266°N,77.375°W;13Jan.2014;CarBioteamleg.;ZFMKCar257.–Risaralda•1♂,inpure ethanol; same collection data as for holotype; ZFMK Col247 (voucher of UH260). PANAMA – Colón•1♂;SanLorenzoProtectedArea;9.267°N,79.967–79.983°W;~150ma.s.l.; 13May2004;J.SchmidlandJ.Bailleg.;fogging;ZMUC•1♂;samelocalityasforpreceding; 15May2004;J.SchmidlandJ.Bailleg.;ZMUC•1♀;samelocalityasforpreceding;17Oct.2003; J.SchmidlandA.Florenleg.;ZMUC•1♂;samelocalityasforpreceding;17Oct.2003;J.Schmidland J.Bailleg.;ZMUC•1♂;samelocalityasforpreceding;12May2003;J.SchmidlandJ.Bailleg.; ZMUC•1♀;samelocalityasforpreceding;27May2004;J.SchmidlandJ.Bailleg.;ZMUC•1♂; samelocalityasforpreceding;8Oct.2004;J.Bailleg.;ZMUC•2♂♂;samelocalityasforpreceding; 15 May 2004; J. Schmidl and J. Bail leg.; ZMUC. Description Male (holotype) MeasureMents. Total body length 2.1, carapace width 0.7. Distance PME–PME 70 µm; diameter PME 90 × 110 µm; distance PME–ALE 30 µm; AME absent. Leg 1: 22.9 (5.7 + 0.3 + 5.4 + 10.3 + 1.2), tibia 2: 3.5, tibia 3: 2.1, tibia 4: 3.3; tibia 1 L/d: 77; diameters of leg femora (at half length) 0.09; of leg tibiae 0.07. Color (in ethanol). Carapace pale ochre-yellow with distinct ochre-brown pattern on posterior half, ocular area and clypeus without dark marks (Fig. 1G–H); sternum mostly whitish, only posteriorly with small ochre mark; legs ochre-yellow, patellae and tibia-metatarsus joints dark brown; abdomen pale ochre-gray, dorsally and laterally with dark marks. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 223 Body. Habitus as in Fig. 1G–H.Ocularareaslightlyraised.Carapacewithoutthoracicgroove.Clypeus withshortmedianprocessatrim(length~30µm).Sternumwiderthanlong(0.56/0.44),unmodified. Abdomen approximately twice as long as wide, dorso-posteriorly pointed. CheliCerae. As in Fig. 19A; with series of ~16–19modified(globular)hairsoneachsideandpairof distal apophyses near fang joints, without proximal lateral processes. Fig. 17. Metagonia embera Huber sp. nov., paratype, ♂, from Colombia, Risaralda, Santa Cecilia (ZFMK Ar 24784). Left and right palps at same scale. A–C. Left palp, prolateral, dorsal, and retrolateral views. D–F. Right palp, retrolateral, dorsal, and prolateral views. Scale line = 0.5 mm. European Journal of Taxonomy 1026: 199–235 (2025) 230 Acknowledgements ForsupportwithfieldworkinColombia,BAHthanksJimmyCabraGarcía(organizationandcollection permit),GermánAndrésRodríguez,WilliamGalvis,andDavidVergaraMoreno(assistanceinthefield), and Pedro Londoño (permit to enter Bosque del Silencio). Colombian specimens were collected under permit #1070 granted by the Autoridad Nacional de Licencias Ambientales (ANLA) to the Universidad delValle.ForsupportwithfieldworkinVenezuela,BAHthanksthedirectorsoftheMuseodel InstitutodeZoologíaAgrícola(Maracay),VilmaSaviniandJoséClavijo,forfacilitatingfieldwork; BorisStriffler,QuintínArias,andOsvaldoVillarrealforsupportinthefield;AbelPérez-Gonzálezfor hishelpwithgettingacollectionpermit,andtheDirecciónGeneraldeFaunayOficinaNacionalde Diversidad Biológica in Caracas for issuing permit No 01-11-0966. Additional specimens from Panama and Colombia were kindly provided by Jan Pedersen (University of Copenhagen) and Ingi Agnarsson (CarBioproject).WethankLauravonderMark(ZFMK)forhelpwithCO1barcoding,andAbelPérezGonzález and an anonymous reviewer for valuable comments on the manuscript. Trips to Venezuela and ColombiawerefinanciallysupportedbytheGermanResearchFoundation(DFG,projectsHU980/1-1, HU 980/13-1, HU 980/14-1). Author contributions BAH: initiation of project, funding acquisition, collecting, taxonomy, writing. GM: curation and analysis of molecular data, writing. Fig. 25. Examples of symmetric (A–C) and antisymmetric (D–F) female internal genitalia in Metagonia Simon, 1893, from Huber & Villarreal (2020). A. M. triocular (González-Sponga, 2011). B. M. guttata Huber, 2020. C. M. guianesa Huber, 2020. D. M. beni Huber, 2000. E. M. latigo Huber, 2020. F. M. conica (Simon, 1893). At various scales. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 231 References Astrin J.J., Huber B.A., Misof B. & Kluetsch C.F.C. 2006. 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The other members of the consortium are: Meise Botanic Garden, Meise, Belgium; Natural History Museum of Denmark, Copenhagen, Denmark; Naturalis Biodiversity Center, Leiden, the Netherlands; Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain; Leibniz Institute for the Analysis of Biodiversity Change, Bonn – Hamburg, Germany; National Museum of the Czech Republic, Prague, Czech Republic; The Steinhardt Museum of Natural History, Tel Aviv, Israël. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 233 Appendix 1. Genital asymmetry in Metagonia Simon, 1893 – an overview. Genital symmetry (blue) and asymmetry (red), mapped on the phylogeny of Metagonia. The tree is an exact copy of the tree published in Huber et al. (2022) except that two new names proposed herein are updated (in Fig. A3: M025 and M092). Light red stands for female asymmetry, which is antisymmetry in all cases where this detail has been studied. Dark red (in Fig. A3 only) stands for directional female and male asymmetry. No color means that the internal female genitalia have not yet been studied. Fig. A1. The Metagonia taruma, petropolis, and bifida groups. Upper inset: relationships to other species groups. Lower inset: position of this clade in the complete tree. European Journal of Taxonomy 1026: 199–235 (2025) 234 Fig. A2. The Metagonia rica and potiguar groups. Inset: position of this clade in the complete tree. HUBER B.A. & MENG G., Asymmetric Metagonia spiders 235 Fig. A3. The Metagonia furcata and delicata groups. Inset: position of this clade in the complete tree.