Dalodesmid millipedes from alpine and subalpine habitats in New South Wales and Victoria, Australia (Diplopoda, Polydesmida, Dalodesmidae)

303 Dalodesmid millipedes from alpine and subalpine habitats in New South Wales and Victoria, Australia (Diplopoda, Polydesmida, Dalodesmidae) Robert Mesibov1 1 Ulverstone, Tasmania, Australia Corresponding author: Robert Mesibov ([email protected]) Copyright: © Robert Mesibov. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International – CC BY 4.0). Research Article Abstract Eleven new species of Dalodesmidae (Diplopoda, Polydesmida) are described: Araneopedis porchi gen. nov. et sp. nov. (type species), A. bogong sp. nov., A. buffalo sp. nov., A. dargo sp. nov., A. gibbae sp. nov.; Cernethia dysmica sp. nov.; Dibologonus sladei gen. nov. et sp. nov. (type species), D. major sp. nov., D. minor sp. nov., D. oedipus sp. nov.; Polydactylogonus sanctogwinear gen. nov. et sp. nov. (type and only species). Males of D. oedipus sp. nov. have modified legpairs 13, 15 or 17, with reduced prefemur, femur and postfemur, and fused, swollen tibia and tarsus. New locality records are presented for the dalodesmids Cernethia inopinata Mesibov, 2015, Lissodesmus milledgei Mesibov, 2006 and Orthorhachis durabilis Mesibov, 2008. Key words: Litter sampling, locality records, new genus, new species, pitfall trapping, taxonomy Introduction Only three species of Dalodesmidae have previously been recorded at high-elevation sites in the mountain ranges of eastern Victoria (Vic) and southeastern New South Wales (NSW) (Mesibov 2008a): Orthorhachis catherinae Mesibov, 2008 (Kosciusko National Park, NSW, 1320 m), O. durabilis Mesibov, 2008 (Mt Buller, Vic, 1560 m) and O. vinnula Mesibov, 2008 (Bennison Plains, Vic, 1310 m). In this paper I describe 11 new alpine and subalpine dalodesmid millipedes from an invertebrate survey conducted in the Australian Alps in 2023–25 by Nicholas Porch (Deakin University) and his students. The survey also returned new localities, reported here, for three previously described dalodesmids. A twelfth new species from the survey, Procophorella bawbawensis Mesibov, 2025, has been separately described and its genus newly placed in Dalodesmidae (Mesibov 2025). Academic editor: Bruce A. Snyder Received: 28 October 2025 Accepted: 26 November 2025 Published: 10 December 2025 ZooBank: https://zoobank.org/ FCCCF129-31BF-4258-BF121D1887B901AA Citation: Mesibov R (2025) Dalodesmid millipedes from alpine and subalpine habitats in New South Wales and Victoria, Australia (Diplopoda, Polydesmida, Dalodesmidae). ZooKeys 1262: 303–333. https://doi.org/10.3897/ zookeys.1262.176273 ZooKeys 1262: 303–333 (2025) DOI: 10.3897/zookeys.1262.176273 304 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Materials and methods All specimens studied came either from litter samples (2023, 2024, 2025) or pitfall traps (2024). Leaf litter samples were collected and Tullgren funnel-extracted by Nicholas Porch and his students. Specimen lots dated 2023 were from single 2 m2 litter patches, and 2024 and 2025 lots were from four combined 0.25 m2 patches collected within 10 m of a pitfall grid. In the type details below, the two methods are referred to as “2 m2 litter sample” and “1 m2 litter sample”, respectively. Pitfall grids at each site comprised 16 plastic tubes set in a 4 × 4 square with traps ca 2–3 m apart. Traps were filled with 25 ml of 80% propylene glycol and removed after approximately two weeks. All specimens of the new species are preserved in 70% or 95% ethanol in Museums Victoria. Selected specimens were dissected for scanning electron microscopy and digital imaging. Whole-animal images were captured either with an OM Systems TG-7 digital camera or with an Omax A35180U3 eyepiece video camera. Gonopods were cleared in 90+% lactic acid, temporarily mounted in a 1:1 glycerol:water mixture and imaged with the Omax camera mounted on an AmScope B210 microscope, with subsequent focus-stacking of manually focused images using Zerene Stacker 1.04 software. Some gonopod figures show the focus-stacked images, while Figs 8B, 14D have outline drawings digitally traced from focus-stacked images. For scanning electron microscopy, material was air-dried and temporarily fixed to stubs prior to platinum coating to 5 nm with a Cressington 208 HR sputter coater and imaging with a Hitachi SU-70 operated in high-vacuum mode. Maps were generated with QGIS 3.22 (https://qgis.org/) and figures were composed and edited with GIMP 2.10 (https://www.gimp.org/). The base map in all map figures is from OpenTopoMap (https://opentopomap.org), with an overlay of major roads from Data Vic (https://discover.data.vic.gov.au/dataset/ vicmap-transport-road-line). All elevations reported are above sea level. Details of all specimen lots for named Dalodesmidae from the Hermon Slade Foundation project are provided in Suppl. material 1 in Darwin Core format. In this paper I use the term “solenomere” for a major process on the gonopod telopodite that carries the opening of the prostatic groove. The term is one of convenience for describing and labelling the process, and I am not suggesting that the structure labelled in this way is homologous with similar processes on the telopodites of other Polydesmida. Abbreviations ACT Australian Capital Territory, Australia; NSW New South Wales, Australia; VIC Victoria, Australia; NMV Museums Victoria, Melbourne; M adult male; F adult female; J juvenile. 305 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Results Taxonomy Order Polydesmida Pocock, 1887 Suborder Dalodesmidea Hoffman, 1980 Family Dalodesmidae Cook, 1896 Araneopedis gen. nov. https://zoobank.org/83711322-8551-445B-8BD5-B5956B3FA3DA Type species. Araneopedis porchi sp. nov., by present designation. Other assigned species. Araneopedis bogong sp. nov., A. buffalo sp. nov., A. dargo sp. nov., A. gibbae sp. nov. Diagnosis. Gonopod telopodite split at 1/3 to 1/2 height into large, erect, similarly sized, lateral and medial branches, with a smaller, shorter, separate, posteromedial solenomere. The only other Australasian dalodesmid with a gonopod split into similarly sized branches with a separate solenomere is Paurodesmus sjoestedti (Verhoeff, 1924) (Mesibov 2008b), but in that species the solenomere is nearly as large as the medial and lateral branches and arises basally, rather than at ca 1/2 telopodite height. Description. Small dalodesmids ca 7–9 mm long with body plan head + 19 rings (including telson). Male colour in alcohol pale brownish-yellow, darker on head, distally on antennae and marginally on tergites and metatergites. Head with vertex sparsely setose, frons and clypeus setose; vertigial sulcus reaching ca 1/2 way to level of line between top of antennal sockets. Sockets separated by ca 2× socket diameter. Antenna almost reaching tergite 3 when manipulated. Relative antennomere lengths (6,3) > 2 > (4,5), 6 widest. Relative tergite widths 6 > 5 > 4 > 3 > 2 > collum; rings 6–16 subequal in width, 17 and 18 narrower. Collum much narrower than head, ovoid in dorsal view, corner rounded. Paranotal margin on ring 2 lower than ring 3 margin; large pit ventrally under ring 2 paranotum. Midbody paranotal margin at ca 2/3 ring height, level; paranotum with anterior corner gently convex, laterally very slightly convex and slightly wider behind, with a few short marginal setae laterally and posteriorly; posterior margin more or less straight; posterior corner slightly projecting on last few rings. Metatergites with 3 transverse rows of low bumps carrying short setae where not abraded; anterior row of bumps narrowest, posterior row widest. Limbus an irregular row of blunt doubled spines. Pore formula normal; ozopore opening dorsally at posterolateral corner of paranotum. Epiproct extending a little beyond anal valves, sides slightly concave, apex truncate; spinnerets in square array. Hypoproct trapezoidal. Sternites slightly wider than long, impressions shallow, transverse impression a little deeper than longitudinal impression. Spiracles small, round or slightly ovoid, on diplosegments with posterior spiracle between leg bases. Length of midbody leg ca 1.5–1.7× midbody ring diameter. Relative podomere lengths tarsus >> (prefemur, femur) >> (postfemur, tibia); tarsus very slightly curved. Anterior legs somewhat swollen, prefemur and femur arched dorsally. Numerous sphaerotrichomes on anterior leg tarsus, tibia; sphaerotrichomes with pointed shafts strongly declined and with 306 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes flattened globular bases. Brush setae on prefemur and femur, tapering to blunt points, often curving proximally. Gonopore opening distomedially on leg 2 coxa. Aperture transversely ovoid, ca 1/2 width of ring 7 prozonite, rim projecting a little posterolaterally. Retracted gonopod telopodites reaching just past leg 6. Ring 6 sternite excavate with short setal brushes laterally, supporting retracted telopodites. Telopodites erect, closely appressed, divided into lateral branch, medial branch and posteromedial solenomere. Female closely similar to male, with shorter legs; epigynum slightly raised, subrectangular; cyphopods not examined in any species. Name. Latin aranea + pedis, “spider-foot”. The well-separated lateral and medial branches on the gonopod telopodite together with the smaller posteromedial solenomere remind me of the two principal claws and smaller median claw on the tarsus of a web-building spider. Gender masculine. Remarks. The five known species of Araneopedis gen. nov. are closely similar in overall appearance and are geographically clustered in the Victorian mountains, with a known genus range of ca 3500 km2 (Fig. 15A). Araneopedis porchi sp. nov. https://zoobank.org/36364101-843C-4060-8689-F17530CE55DE Figs 1, 2, 15A Type material. Holotype. Male, Bogong High Plains, Pretty Valley Road, 1.2 km SE of Mt McKay, site HS01-C-L1, -36.8823, 147.2534 ± 25 m, 1725– 1745 m, coll. Nicholas Porch, 2024-04-22, 1 m2 litter sample from closed shrubby snow gum woodland, NMV K16475. Paratypes. 6M, 11F, details as for holotype, NMV K16476; 1M, same details but site HS01-C-P1, pitfall sample, NMV K16477; 8M, 11F, same details but 1.25 km SE of Mt McKay, site HS01-C-L2, -36.8824, 147.2537 ± 25 m, 1730–1750 m, 1 m2 litter sample, NMV K16465; 1M in 95% EtOH, same details, NMV K16466; 5M, 5F, same details but 1.3 km SE of Mt McKay, site HS01-C-L3, -36.8828, 147.2539 ± 25 m, 1735–1755 m, NMV K16474. Additional material. 51M, 64F, 1J from nine other sites. See Suppl. material 1 for details. Diagnosis. Adult males distinguished from Araneopedis buffalo sp. nov. by the similar sizes of posterior rings vs enlarged rings; from A. buffalo sp. nov. and A. gibbae sp. nov. by the undivided vs divided lateral branch; from A. dargo sp. nov. by the equally tall lateral and medial branches vs much taller medial branch; and from A. bogong sp. nov. by the simply curved solenomere vs solenomere with a wide distal-facing concavity. Description. As for the genus, with the following details. Male/female length ca 7/7 mm, maximum midbody width 0.6/0.6 mm, midbody metatergite width 1.5× prozonite width. Telopodite (Fig. 1) with basal margin upturned. Telopodite erect, bulging posteriorly at ca 1/4 telopodite height, sparsely setose posteriorly at base and posterolaterally, divided at ca 1/2 telopodite height into lateral and medial branches of equal height. Lateral branch (Fig. 1) somewhat flattened anteroposteriorly, C-shaped with concavity on posterior side, tip directed posteriorly and bluntly pointed. Medial branch with rounded shoulder laterally at base, bent 307 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes a little laterally before extending distally, widening slightly and bent posteriorly at apex, the tip with blunt tooth at lateral corner. Solenomere arising posterior to telopodite division, expanded posteriorly, curving laterally and flattening mediolaterally, the posterior edge forming a rounded triangle, then tapering strongly and bending posteriorly, the tip pointed posteriorly below lateral and medial branch tips. Prostatic groove running on medial surface of telopodite and along anterior edge of solenomere to open at solenomere tip. Name. Noun in the genitive case, in honour of Nicholas Porch (Deakin University), principal investigator for the Hermon Slade Foundation project in which this and other new millipede species were collected. Distribution. Collected from two locality clusters near Mt Hotham and Mt McKay in the Victorian mountains (Fig. 15A) with a linear range of ca 16 km, in alpine and subalpine grassland and woodland from 1725 to 1860 m. Possibly parapatric with A. bogong sp. nov. Figure 1. Araneopedis porchi sp. nov., paratype male ex site HS01-C-L2, NMV K16465. Lateral (A), posterior (B) and (C) medial views of cleared right gonopod telopodite; composite focus-stacked images. Abbreviations: l = lateral branch, m = medial branch, s = solenomere. 308 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Remarks. Although the live colouring of A. porchi sp. nov. is currently unknown, specimens that were pitfall-trapped in propylene glycol are all almost uniformly darker brown (Fig. 2B). Propylene glycol may have stabilised colouring that was partially lost in the ethanol into which litter specimens were collected. Araneopedis bogong sp. nov. https://zoobank.org/E2EC364D-9014-4080-8F89-3931B501146F Figs 3, 15A Type material. Holotype. Male, Bogong High Plains (Vic), 0.37 km E by N of junction of Bogong High Plains Road and Big River Firetrail, site HS03-C-L2, -36.8725, 147.3218 ± 25 m, 1645–1665 m, coll. Nicholas Porch, 2024-04-22, 1 m2 litter sample from closed shrubby snow gum woodland, NMV K16482. Paratypes. 3F, details as for holotype, NMV K16481; 1M in 95% EtOH, same details but 0.2 km E by N of junction of Bogong High Plains Road and Big River Firetrail, site HS03-C-L1, -36.8730, 147.3199 ± 25 m, 1620–1640 m, NMV K16480; 1M, 8F, same details, NMV K16483; 1M, same details but Dinner Plain area, 0.51 km SSW of JB Plain carpark, site HS07-C-L3, -37.0264, 147.2187 ± 25 m, 1650 m, 2024-04-14, closed grassy/shrubby snow gum woodland, NMV K16484. Additional material. None. Figure 2. Araneopedis porchi sp. nov. males. A. Ex site HS02-O-L1, NMV K16467, litter extraction. B. Ex site HS02-O-P1, NMV K16478, pitfall trap. 309 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Diagnosis. Adult males distinguished from Araneopedis buffalo sp. nov. by the similar sizes of posterior rings vs enlarged rings; and from other species of Araneopedis gen. nov. by the solenomere flattened and with a wide distal-facing concavity. Description. As for the genus, with the following details. Male/female length ca 9.0/9.0 mm, maximum midbody width 0.8/0.8 mm, midbody metatergite width ca 1.4× prozonite width. Telopodite base with upturned basal margin (Fig. 3A), sparsely setose. Division of telopodite into lateral and medial branches and solenomere at ca 1/2 telopodite height; telopodite bulging posteriorly below division. Lateral branch (Fig. 3B) a little taller than medial branch, narrow, flattened mediolaterally, bowed medially, tip curving posteriorly and pointed, lateral margin with triangular extension at ca 3/4 branch height. Medial branch widening from base and broadly truncate, concave posteriorly. Solenomere mediolaterally flattened, extending distally, then curving anterodistally, creating wide distal-facing concavity in profile, then tapering and curving posteriorly and terminating in posteriorly directed point with the opening of the prostatic groove. Name. Noun in apposition, for the Bogong High Plains, from which most of the known specimens were collected. Distribution. Collected from two locality clusters near Dinner Plain and east of Falls Creek in the Victorian mountains (Fig. 15A), a linear range of ca 19 km, in subalpine woodland from 1620 to 1665 m. Possibly parapatric with A. porchi sp. nov. Figure 3. Araneopedis bogong sp. nov., paratype males ex site HS07-C-L3, NMV K16484 (A) and site HS03-C-L1, NMV K16483 (B, C). A. Posterior view of gonopods in situ; B, C. Medial and anteromedial views of cleared right gonopod telopodite; focus-stacked images. Abbreviations: l = lateral branch, m = medial branch, s = solenomere. 310 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Araneopedis buffalo sp. nov. https://zoobank.org/E086C259-3332-4ECA-8DC0-508CCD04C747 Figs 4, 5A, 15A Type material. Holotype. Male, Mt Buffalo (Vic), 0.5 km SE by E of Mt Buffalo Park Office, site HS15-C-L1, -36.7281, 146.8079 ± 25 m, 1380–1400 m, coll. Nicholas Porch, 2024-04-13, 1 m2 litter sample from closed shrubby subalpine woodland, NMV K16486. Paratypes. 2M, 5F, details as for holotype but 0.3 km ESE of Cresta Valley carpark entrance, site HS13-O-L3, -36.7655, 146.7884 ± 25 m, 1465–1485 m, open herb-rich subalpine grassland, NMV K16488; 1M in 95% EtOH, same details, NMV K16485; 2M, 4F, same details but 0.29 km SE of Mt Buffalo Park Office, site HS15-C-L2, -36.7274, 146.8059 ± 25 m, 1370 m, closed shrubby subalpine woodland, NMV K16487. Additional material. 2M from two other sites. See Suppl. material 1 for details. Figure 4. Araneopedis buffalo sp. nov., paratype males ex site HS15-C-L2, NMV K16487 (A), and site H13-O-L3, NMV K16488(B). A. Gonopods in situ; B. Lateral view of cleared right gonopod telopodite, composite focus-stacked image. Abbreviations: l = lateral branch, m = medial branch, s = solenomere. 311 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Diagnosis. Adult males distinguished from other species of Araneopedis gen. nov. by the posterior rings being enlarged vs of similar size to anterior rings (Fig. 5). Distinguished from A. bogong sp. nov. by the lack of a wide distal-facing concavity in the solenomere; from A. porchi sp. nov. and A. dargo sp. nov. by the terminal division of the lateral branch of the gonopod telopodite; and from A. gibbae sp. nov. by much larger size and presence of a terminal, posteriorly directed spine on the medial branch. Description. As for the genus, with the following details. Male/female length ca 9.0/8.5 mm, maximum midbody width 0.9/0.8, midbody metatergite width 1.3× prozonite width. Telopodite base with upturned basal margin (Fig. 4A), sparsely setose. Lateral branch arising lower on telopodite than medial branch + solenomere at ca 1/2 telopodite height, somewhat flattened mediolaterally, curving anterodistally, divided at ca 1/3 branch height into medial process and shorter lateral process with two posteriorly directed subapical teeth; medial process expanded medially Figure 5. A. Araneopedis buffalo sp. nov., holotype male ex site HS15-C-L1, NMV K16486; B. A. gibbae sp. nov., holotype male ex site HS22-C-L3, NMV K16495. 318 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Gonopore small, opening distomedially on leg 2 coxa. Gonocoxae small, subconical, lightly joined distomedially. Aperture a little longer than wide, ca 1/2 ring 7 prozonite width, margin produced posterolaterally. Gonopod telopodites slender, straight, split into medial branch and lateral solenomere; ring 6 sternite excavate to accommodate retracted telopodites, with small tufts of setae above leg bases. Prostatic groove running from medial surface at telopodite base across posterior surface, then between medial branch and solenomere and curving in spiral around solenomere (left-handed spiral on left telopodite, right-handed spiral on right telopodite). Name. Greek dibolos (“two-pointed”) plus “-gonus”, an ending for genus names in Polydesmida that refers to gonopod structure. The gonopod telopodite is split into two parallel processes. Gender masculine. Remarks. The four species of Dibologonus gen. nov. are partly distinguishable by adult size, but more reliably by differences in the structure of the gonopod telopodite. As the telopodite processes are tightly packed together, these differences are best seen under high magnification (Fig. 9). Species of Dibologonus gen. nov. occur widely in eastern Victoria and southeastern New South Wales (Fig. 16A), and more species (or significant range extensions) are likely to be found in future. Dibologonus sladei sp. nov. https://zoobank.org/ED34DE1A-DB54-4AB4-97B5-02C79F503081 Figs 9A, 10, 16A Type material. Holotype. Male, Dargo High Plains Road (Vic), 90 m S by W of King Spur Track junction, site HS10-C-L3, -37.1134, 147.1662 ± 25 m, 1575– 1595 m, coll. Nicholas Porch, 2024-04-14, 1 m2 litter sample from closed snow gum woodland, NMV K15999. Paratypes. 13M, 24F, details as for holotype, NMV K16005; 6M, 14F, same details but 0.14 km SE by E of King Spur Track junction, site HS10-C-L1, -37.1134, 147.1677 ± 25 m, 1565–1585 m, NMV K16002; 1M, same details but in 95% EtOH, NMV K15998; 12M, 13F, same details but 0.13 km S by E of King Spur Track junction, site HS10-C-L2, -37.1137, 147.1669 ± 25 m, 1570–1590 m, NMV K16004. Additional material. 11M, 15F from five other sites. See Suppl. material 1 for details. Diagnosis. Much larger than D. minor sp. nov. and D. oedipus sp. nov. Solenomere with apex not expanded as in D. major sp. nov. and D. oedipus sp. nov.; major telopodite division into medial branch and solenomere at ca 1/3 telopodite height vs 2/3 height as in D. minor sp. nov. Description. As for the genus, with the following details. Colour in alcohol brownish-yellow with pale brown at collum and paranotal margins. Adult male/ female approximate measurements: length 14/14 mm, maximum midbody width 1.5/1.5 mm. Brush setae dense, tips curving distally and with mid-height notch on distal surface (Fig. 10A); sphaerotrichomes with slightly flattened globular base, shafts with rounded tips curving distally (Fig. 10B). Gonopod telopodites (Figs 9A, 10C) almost reaching legpair 4 when retracted, setose posterolaterally to ca 1/3 telopodite height. Telopodite divided into medial branch and solenomere at ca 1/3 telopodite height. Medial 319 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes branch divided at ca 1/2 telopodite height into parallel anteromedial and posterolateral processes, both processes somewhat flattened; anteromedial process with blunt, rounded tip below level of solenomere; posteromedial process shorter than anteromedial, with truncate tip. Solenomere divided at ca 3/4 telopodite height into anterolateral process and much shorter, parallel, posteromedial process, the latter somewhat flattened and tapering to point. Anterolateral process somewhat flattened, curving a little laterally, bending medially at apex and dividing into two short, tooth-like processes, the prostatic groove opening on the proximal tooth. On the anterior surface of the telopodite at ca 1/2 telopodite height, a prominent triangular tab (Fig. 10C) with apex directed anterobasally. Female approximately the same length as male but a little stouter and with thinner legs. Epigynum raised medially in low, rounded triangle; cyphopods not examined. Name. Noun in the genitive case, in honour of George Hermon Slade (1910– 2002), Australian chemist, orchidologist and founder of the Hermon Slade Foundation for support of research in the natural sciences. Distribution. Collected over a ca 55 km linear range from Mt Buffalo National Park to the Dargo High Plains (Fig. 16A), in subalpine woodland from 1500 to 1640 m. Remarks. None of the males examined have modified legs as seen in D. oedipus sp. nov. Figure 9. Dibologonus gen. nov., gonopods in situ. A. D. sladei sp. nov., paratype ex site HS10-C-L3, NMV K16005; B. D. major sp. nov., paratype ex site NP23-18, NMV K16010; C. D. minor sp. nov., paratype ex site NP23-11, NMV K16505; D. D oedipus sp. nov., paratype ex site HS40-C-L2, NMV K16526. Scale bars: 0.5 mm. 320 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Dibologonus major sp. nov. https://zoobank.org/E4E92624-6A4A-492E-8486-3BB3FE9EEB08 Figs 9B, 11, 16A Type material. Holotype. Male, Baw Baw National Park (Vic), 0.5 km NNE of Mt St Gwinear carpark, site NP23-18, -37.8368, 146.3346 ± 25 m, 1270 m, coll. Nicholas Porch, 2023-03-15, 2 m2 litter sample from riparian cool temperate rainforest, NMV K16008. Paratypes. 2M, details as for holotype, NMV K16010; 1M in 95% EtOH, same details but Mt St Gwinear Road, 1.1 km WNW of junction with Thomson Valley Road, site NP23-20, -37.8163, 146.3456 ± 25 m, 1035 m, wet sclerophyll forest, NMV K16009. Additional material. None. Diagnosis. Much larger than D. minor sp. nov. and D. oedipus sp. nov. Solenomere with apex expanded vs not expanded in D. sladei sp. nov.; the major telopodite division into medial branch and solenomere at ca 1/3 telopodite height vs 2/3 height in D. minor sp. nov.; solenomere obscuring medial branch vs well-separated from medial branch in D. oedipus sp. nov. Description. As for the genus, with the following details. Male colour in alcohol pale yellow, sometimes with fine reddish-brown speckling at collum and paranotal margins. Length ca 13 mm, maximum midbody diameter 1.6 mm. Antenna reaching tergite 3 when manipulated dorsally; relative antennomere lengths 3 > (2,6) > (4,5); 6 widest. Metatergites with posterior corners projecting a little, more on rings 14–17. Midbody leg ca 1.4× ring diameter. Brush setae (Fig. 11A) dense, tapering to point curving distally on coxa/trochanter, prefemur, femur, with a few on postfemur, without midFigure 10. Dibologonus sladei sp. nov. A, B. Paratype male ex site HS10-C-L3, NMV K16005; C. paratype male ex site HS10-C-L1, NMV K16002; A. Leg 4 brush setae on prefemur (distal to right); B. Leg 4 sphaerotrichomes on tarsus (distal to left); C. Medial view of cleared right gonopod telopodite; focus-stacked image. Abbreviation: t = anterior tab. 321 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes height notch; sphaerotrichomes (Fig. 11B) on postfemur, tibia and tarsus with flattened globular base and tapering shaft, the shaft declined distally and flattened. Gonopod telopodites (Figs 9B, 11C) straight, almost reaching legpair 4 when retracted, setose posterolaterally to ca 1/3 telopodite height. Telopodite divided at ca 1/2 height into medial branch and solenomere. Medial branch gradually tapering, divided near base into medial and lateral processes tapering to points, the lateral process a little longer. Solenomere gently curving medially near base, divided at ca 3/4 telopodite height into posteromedial and anterolateral processes. Posteromedial process stout, pointed, terminating below other telopodite processes. Anterolateral process subcylindrical, expanding near tip and divided into a stout, pointed, lateral subprocess and a medial subprocess curving medially towards the lateral subprocess tip, and with small subapical tooth curving posterodistally and carrying the termination of the prostatic groove. Name. Adjective; Latin major, “greater”. This is the larger of the two species of Dibologonus gen. nov. co-occurring near Mt Baw Baw. Distribution. Collected at two sites ca 2.5 km apart near Mt St Gwinear (Fig. 16A), in wet sclerophyll forest at 1035 m and cool temperate rainforest at 1270 m. Co-occurs with D. minor sp. nov. Remarks. No females of this species have yet been recognised, and none of the four males examined have modified legs as seen in D. oedipus sp. nov. Figure 11. Dibologonus major sp. nov., paratype male ex site NP23-18, NMV K16010. A. Leg 6 brush setae on prefemur (distal to left); B. Leg 6 sphaerotrichomes on tarsus (distal to right); C. Distal portion of left gonopod telopodite. Abbreviations: ap = anterolateral process of solenomere, lp-mb = lateral process of medial branch, pg = prostatic groove, pp = posteromedial process of solenomere, t = tooth with opening of prostatic groove. 322 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Dibologonus minor sp. nov. https://zoobank.org/189FABEC-250B-44D3-9A84-E83FFF10A8F7 Figs 9C, 12, 16A Type material. Holotype. Male in 95% EtOH, Mt Baw Baw, 0.43 km S by W of Mt Baw Baw summit, site HS20-C-L3, -37.8433, 146.2748 ± 25 m, 1410– 1430 m, 2024-02-13, coll. Nicholas Porch and Daniel Kurek, 1 m2 litter sample from closed shrubby subalpine woodland, NMV K16012. Paratypes. 1M, 2F, Baw Baw Tourist Road, 0.79 km WNW of Baw Baw Alpine Resort entrance, site NP23-11, -37.8475, 146.2324 ± 25 m, 760 m, 2023-03-05, coll. Nicholas Porch, 2 m2 litter sample from snow gum woodland, NMV K16505; 2M, same details but Baw Baw Alpine Reserve, near NE middle of carpark 3, site NP23-05, -37.8382, 146.2611 ± 25 m, 1460 m, NMV K16503; 1F, same details but Baw Figure 12. Dibologonus minor sp. nov., paratype males. A. Ex site HS27-O-L3, NMV K16014; B. Ex site NP23-11, NMV K16505. A. Focus-stacked medial view of distal end of cleared left gonopod telopodite; B. Posterior view of distal ends of gonopod telopodites; C. Sphaerotrichomes on leg 4 tarsus. Abbreviations: ap = anterolateral process, l = lateral process, m = the two medial process divisions of medial branch, pg = prostatic groove, pp = posteromedial process, s = solenomere. 323 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Baw Alpine Reserve, 40 m N of Saxons Picnic Area, site NP23-08, -37.8354, 146.2589 ± 25 m, 1435 m, NMV K16011; 1M, 2F, same details but Baw Baw Alpine Reserve, 0.1 km NE by E of Saxons Picnic Area, site NP23-10, -37.8352, 146.2599 ± 25 m, 1430 m, NMV K16504; 1M, same details but Baw Baw National Park, 0.5 km NNE of Mt St Gwinear carpark, site NP23-18, -37.8368, 146.3346 ± 25 m, 1270 m, 2023-03-15, NMV K16013; 2M, same details but Mt Baw Baw Alpine Reserve, 0.35 km W of Mt Baw Baw summit, site HS27-O-L3, -37.8371, 146.2734 ± 25 m, 1560 m, coll. Nicholas Porch and Aidan Fitt, grassy/shrubby snow gum woodland, NMV K16014. Additional material. None. Diagnosis. Much smaller than D. sladei sp. nov. and D. major sp. nov. Distinguished from the other three species of Dibologonus gen. nov. in having the major division into medial branch and solenomere at ca 2/3 telopodite height vs 1/3 height. Description. As for the genus, with the following details. Colour in alcohol pale yellow, sometimes with fine reddish-brown speckling at collum and paranotal margins. Adult male/female approximate measurements: length 8/9 mm, maximum midbody diameter 0.8/0.9. Male with antenna almost reaching tergite 3 when manipulated dorsally; relative antennomere lengths 6 > 3 > 2 > (4,5); 6 widest. Metatergites slightly wider posteriorly, midbody metatergite width ca 1.2× prozonite width. Midbody leg ca 1.4× ring diameter. Brush setae tapering to point curving a little proximally, with mid-height notch as in D. sladei sp. nov. on coxa/trochanter, prefemur, femur; sphaerotrichomes (Fig. 12C) on postfemur, tibia and tarsus with very small globular base and pointed shaft, the tip not curving. Gonopod telopodites (Figs 9C, 12A, B) straight, almost reaching legpair 5 when retracted, sparsely setose posterolaterally to ca 1/2 telopodite height. Telopodite divided at ca 2/3 telopodite height into medial branch and solenomere. Medial branch divided near base into medial and lateral processes, the medial process shorter and further divided into parallel, bluntly pointed subprocesses; medial branch hidden in posterior view by solenomere. Solenomere divided at ca 3/4 telopodite height into anterolateral process and posteromedial process, with small rounded tooth on posterior telopodite surface near division. Anterolateral process flattened, curving slightly medially near tip, the apex with a cluster of four or five small teeth. Posteromedial process with small, horn-like, posterior subprocess curving laterally, the prostatic groove terminating at tip; posteromedial process then extending distally as flattened subprocess, becoming cylindrical and curving posterolaterally, with minute teeth on margins and at apex, and with small, basally directed tooth above horn-like subprocess. Female a little larger than male, epigynum subrectangular; cyphopods not examined. Name. Adjective; Latin minor, “less”. This is the smaller of the two species of Dibologonus gen. nov. co-occurring near Mt Baw Baw. Distribution. Collected over a ca 9 km linear range near Mt Baw Baw (Fig. 16A), in subalpine woodland and riparian rainforest from 760 to 1560 m. Co-occurs with D. major sp. nov. Remarks. None of the males examined have modified legs as seen in D. oedipus sp. nov. 324 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Dibologonus oedipus sp. nov. https://zoobank.org/853C5D0A-A66E-40B8-9F8E-835F8486CAB0 Figs 9D, 13, 16A Type material. Holotype. Male, Kosciuszko National Park (NSW), 0.49 km NE of Rennix Gap, site HS41-O-L3, -36.3579, 148.5060 ± 25 m, 1580 m, coll. Nicholas Porch, 2025-02-22, 1 m2 litter sample from open shrubby subalpine grassland, NMV K16511. Paratypes. 8M, 17F, details as for holotype, NMV K16516; 7M, 2F, same details but 0.58 km NNE of Rennix Gap, site HS40-C-L2, -36.3561, 148.5046 ± 25 m, 1600 m, coll. Nicholas Porch and Aidan Fitt, 2025-02-09, closed shrubby subalpine woodland, NMV K16526; 1M, same details but in 95% EtOH, NMV K16510; 9M, 1F, same details but 0.52 km NNE of Rennix Gap, site HS40-C-L3, -36.3579, 148.5060 ± 25 m, 1595 m, NMV K16506. Additional material. 16M, 33F, 3J from 16 other sites. See Suppl. material 1 for details. Diagnosis. Smaller than D. sladei sp. nov. and D. major sp. nov. Distinguished from D. minor sp. nov. in having the major telopodite division at 1/3 telopodite height vs 2/3 height; distinguished from D. sladei sp. nov. by the expanded vs non-expanded apex of the solenomere; distinguished from D. major sp. nov. by the solenomere being well-separated from the medial branch, not obscuring it. In most male specimens, distinguished from D. sladei sp. nov., D. major sp. nov. and D. minor sp. nov. by modified right and left legs 13, 15 or 17. Description. As for the genus, with the following details. Colour in alcohol uniformly pale yellow, sometimes with fine brown speckling at collum and paranotal margins. Adult male/female approximate measurements: length 9/8 mm, midbody diameter 0.9/0.8. Male with antenna almost reaching tergite 3 when manipulated dorsally; relative antennomere lengths 6 > 3 > 2 > (4,5); 6 widest. Posterior corners of paranota not projecting. Midbody metatergite width ca 1.2× prozonite width. Midbody leg ca 1.7× ring diameter. Legpairs 13, 15 or 17 may be greatly modified: prefemur, femur, postfemur and claw reduced in length, tibia and tarsus fused into swollen structure with dense ventral setation (Fig. 13A). Brush setae dense, tapering to slightly curved point, without mid-height notch, on coxa/ trochanter, prefemur, femur; sphaerotrichomes with slightly flattened globular base and pointed shaft on postfemur, tibia and tarsus. Gonopod telopodites (Figs 9D, 13B) straight, almost reaching legpair 5 when retracted. Telopodite divided at ca 1/3 telopodite height into medial branch and solenomere. Medial branch flattened, with small, tab-like posterolateral extension at ca 1/2 branch height; divided at ca 3/4 telopodite height into closely appressed medial and lateral processes: medial process shorter, flattened, tapering to blunt point; lateral process subcylindrical, tapering to blunt point a little distal to first division of solenomere. Solenomere well-separated from medial branch, divided at ca 7/8 telopodite height into medial and lateral processes, closely appressed, the lateral process tapering and terminating at level of prostatic groove opening on medial process. Medial process divided into leaf-like lateral portion curving medially, with small triangular extension on posterior margin, and well-separated, shorter, medial portion terminating in 3 small teeth, the central tooth having the prostatic groove opening and the most lateral tooth bluntly bifurcate. 325 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Female a little smaller than male and with thinner, legs never modified; epigynum raised medially in low, rounded triangle; cyphopods not examined. Name. Noun in apposition, for the mythical king Oedipus of Thebes, whose name means “swollen foot”. See Remarks for notes on modified podomeres in this species. Distribution. Collected over a ca 125 km linear range from Namadgi National Park in the Australian Capital Territory to Kosciuszko National Park in New South Wales (Fig. 16A), in subalpine woodland and shrubland from 1485 to 1880 m. Remarks. Modified legpairs 13, 15 or 17 are found in males across the range of D. oedipus sp. nov. and are not restricted to particular areas. Among the males with modified legs, all specimens with intact legs have modifications on both the left and right posterior legs on a particular ring. Six males have modifications on leg 13 (ring 9), one on leg 15 (ring 10) and 17 on leg 17 (ring 11). A single male (with intact legs) has no leg modifications. Variation in which legs are modified appears within populations: site HS42-C-L1 had three males with modified leg 13 and one with modified leg 17, while site HS47-C-L2 had one male without modifications, one with modified leg 15 and two with modified leg 17. Similarly swollen distal podomeres were reported by Shear et al. (2022) in two males of the chordeumatidan Amplaria oedipus Shear, Nosler and Marek, 2022 from Cape Mountain, Oregon, USA. In both specimens the swollen podomeres were on legpairs 5 and 6. Figure 13. Dibologonus oedipus sp. nov., paratype male ex site HS40-C-L2, NMV K16526. A. Modified left leg 17; B. Posterior view of distal portion of left gonopod telopodite. Abbreviations: ct = central tooth, l = lateral process of solenomere, lpo = lateral portion of solenomere medial process, mp = medial process of solenomere, mpo = medial portion of solenomere medial process, pg = prostatic groove, s = solenomere. 326 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Polydactylogonus gen. nov. https://zoobank.org/1544D3FE-FB19-49E0-BBC1-572229C40722 Type species. Polydactylogonus sanctogwinear sp. nov., by present designation. Other assigned species. None. Diagnosis. Distinguished from other Australian dalodesmids by the slender gonopod telopodite ending in a fan-like cluster of five branches. Description. As for the type species. Name. Greek polys (many) + dactylos (finger), plus “-gonus”, an ending for genus names in Polydesmida that refers to gonopod structure, e.g. Tridactylogonus Jeekel, 1982. In anterior and posterior view the gonopod telopodite seems to end in five “fingers” spread apart. Masculine gender. Polydactylogonus sanctogwinear sp. nov. https://zoobank.org/88234924-B8F3-439D-923A-B3405249B427 Figs 14, 15B Type material. Holotype. Male, Baw Baw National Park (Vic), 0.26 km NNW of Mt St Gwinear carpark, site NP23-13, -37.8388, 146.3306 ± 25 m, 1325 m, coll. Nicholas Porch, 2023-03-15, 2 m2 litter sample from snow gum woodland, NMV K16527. Paratypes. 7M, details as for holotype, NMV K16531; 1M in 95% EtOH, details as for holotype, NMV K16528; 1M, same details but 0.14 km N by W of Mt St Gwinear carpark, site NP23-14, -37.8396, 146.3315 ± 25 m, 1315 m, NMV K16529; 4M, same details but 0.11 km W by N of Mt St Gwinear carpark, site NP23-15, -37.8407, 146.3307 ± 25 m, 1305 m, NMV K16530. Additional material. None. Description. Small dalodesmids ca 7 mm long with body plan head + 19 rings (including telson). Male colour in alcohol almost uniformly pale white, with reddish speckling at paranotal margins on some specimens. Head with vertex sparsely setose, frons and clypeus setose; vertigial sulcus reaching ca 1/2 way to level of line between top of antennal sockets. Sockets separated by ca 1.5× socket diameter. Antenna strongly clavate, reaching tergite 3 when manipulated. Relative antennomere lengths (6,3,2) > (4,5), 6 widest. Relative tergite widths 6 > 5 > 2 > 4 > 3 > collum; rings 7–16 subequal in width, 17 and 18 narrower. Collum much narrower than head, half-moon-shaped in dorsal view, corner rounded. Paranotal margin on ring 2 much lower than ring 3 margin; no pit ventrally under ring 2 paranotum. Midbody paranotal margin level, at ca 2/3 ring height; paranotum with anterior corner rounded, lateral margin gently convex with setae at three marginal notches, notches more obvious on posterior rings; posterior margin more or less straight; posterior corners not projecting. Midbody metatergite ca 0.6 mm wide, ca 1.2× prozonite width. Waist pronounced; prozonite posteriorly with small, tab-like elements clearly marking suture line; metatergites with three transverse rows of low bumps, the anterior bumps smallest, each bump bearing a single seta posteriorly; posterior margin of metatergite with 4th transverse row of setae. Limbus composed of flat elements with minute, irregular, pointed branches (Fig. 14B). Pore formula normal; ozopore small, round, opening dorsally at posterolateral corner of paranotum. Epiproct extending a little beyond anal valves, conical, apex truncate. Spinnerets in square array, not in depression on epiproct. Hypoproct subtrapezoidal. Sternites 327 ZooKeys 1262: 303–333 (2025), DOI: 10.3897/zookeys.1262.176273 Robert Mesibov: New dalodesmid millipedes Figure 14. Prodactylogonus sanctogwinear gen. nov. et sp. nov.; paratype males ex site NP23-13, NMV K16531. A. Posterodistal view of gonopod telopodite tips in situ; B. Limbus on midbody ring; C. Sphaerotrichomes on leg 5 tarsus; D. Outline sketch anteromedial (left) and posterior (right) views of left gonopod telopodite; dotted line marks course of prostatic groove. Abbreviations: am = anteromedial branch, al = anterolateral branch, l = lateral branch, pl = posterolateral branch, s = solenomere.