A new species of Bent-toed gecko (Squamata: Gekkonidae: Cyrtodactylus Gray, 1827) from the Garo Hills, Meghalaya State, north-east India, and discussion of morphological variation for C. urbanus

Recent taxonomic and systematic research on Cyrtodactylus khasiensis has found that this nomen comprises a large number of superficially similar but deeply divergent species-level taxa from throughout north-east India and surrounding countries. In this study we focus on the taxonomic status of recently surveyed populations from the East Garo Hills and West Garo Hills districts and a single specimen collected from Ri Bhoi District in Meghalaya State, north-east India. Based on a combination of morphological and molecular data we found that the Ri Bhoi specimen is conspecific with the recently described C. urbanus, and that the Garo Hills populations represent a new species of Cyrtodactylus described herein. Molecular analyses (using the NADH dehydrogenase 2, nd2 and adjoining tRNA genes) demonstrate that the new species is nested within the khasiensis group of the Indo-Burma radiation of Cyrtodactylus, and is well-supported as sister to a clade that comprises C. septentrionalis and C. guwahatiensis. We morphologically compare the new C. urbanus specimen with the original description of the species, identify a number of errors and ambiguities in the original description, and notably expand the known morphological variation for the species based on 23 characters. The discovery of an endemic new species of lizards from the Garo Hills further highlights the region as an overlooked centre of biodiversity importance. We discuss several misidentifications in the literature of other reptile species from the region emphasising the need for further attention by taxonomists to review the herpetofauna of the Garo Hills.</jats:p

The phylogenetic position of the enigmatic Assam day gecko Cnemaspis cf. assamensis (Squamata: Gekkonidae) demonstrates a novel biogeographic connection between Northeast India and south India-Sri Lanka

Abstract Northeast Indian biodiversity has long been considered to have a stronger affinity to Southeast Asian rather than Peninsular Indian fauna, however, few molecular phylogenetic studies have explored this hypothesis. In Asia, the polyphyletic gekkonid genus Cnemaspis sensu lato is comprised of two distantly related groups; one primarily from South Asia with some members in Southeast Asia, and the other exclusively from Southeast Asia. Cnemaspis assamensis is a systematically obscure and geographically isolated species (&gt;1400 km from its nearest congeners) from the Brahmaputra River Valley in Northeast India. We provide the first molecular phylogenetic assessment of this species based on a partial ND2 gene fragment. Cnemaspis assamensis is determined to be a deeply divergent (Oligocene) member of the South Asian radiation and is sister to the podihuna clade which is endemic to Sri Lanka. The biogeographic implications of this find are discussed and this is suspected to represent a rare example of true disjunction between the wet zones of Northeast India and southern India/Sri Lanka. These results further emphasise the importance of Northeast India as a refuge for unique ancient faunal lineages.</jats:p

Cryptic diversity within the Megophrys major species group (Amphibia: Megophryidae) of the Asian Horned Frogs: Phylogenetic perspectives and a taxonomic revision of South Asian taxa, with descriptions of four new species

Mahony, Stephen, Kamei, Rachunliu G., Teeling, Emma C. (2018): Cryptic diversity within the Megophrys major species group (Amphibia: Megophryidae) of the Asian Horned Frogs: Phylogenetic perspectives and a taxonomic revision of South Asian taxa, with descriptions of four new species. Zootaxa 4523 (1): 1-96, DOI: https://doi.org/10.11646/zootaxa.4523.1.

Megophrys (Xenophrys) periosa Mahony & Kamei & Teeling 2018, sp. nov.

Megophrys (Xenophrys) periosa sp. nov. (Figures 22 & 23; Table 1) Holotype. Adult male (BNHS 6055 [field no. SDBDU 2009.793]: Figures 22, & 23A & H), from Pangin town (28°12'33.96"N, 94°59'10.02"E, 450 m asl.), East Siang district, Arunachal Pradesh state, Northeast India, collected by members of the Systematics Lab, University of Delhi on 26 July 2009. Paratypes. Four adult males (BNHS 6057 [field no. SDBDU 2009.794]: Figure 23B; BNHS 6058–6060 [field nos. SDBDU 2009.1170 – 1172]: Figure 23H), collected along with the holotype by members of the Systematics Lab, University of Delhi on 26–28 July 2009; four adult males (BNHS 6061 [field no. SDBDU 2009.1243]: Figure 23E; BNHS 6062 [field no. SDBDU 2009.1244], BNHS 6063–6064 [field nos. SDBDU 2009.1265 – 1266]: Figure 23G), and one adult female (BNHS 6056 [field no. SDBDU 2009.1285]: Figure 23F), from the Sessa River, nearby Sessa village (27°6'4.02"N, 92°31'38.52"E, 1110 m asl.), West Kameng district, Arunachal Pradesh state, Northeast India, collected by members of the Systematics Lab, University of Delhi on 07–09 August 2009. Referred specimens. Two adult males (SDBDU 2009.1189: Figure 23D; SDBDU 2009.1190: Figure 23C), from Rigo Village (28°9'34.56"N, 94°47'19.38"E, 260 m asl.), Along town, West Siang district, Arunachal Pradesh state, Northeast India, collected by Systematics Lab members on 30 July 2009; one adult male (SDBDU 2009.1267), from the Sessa River, nearby Sessa village (27°6'4.02"N, 92°31'38.52"E, 1110 m asl.), West Kameng district, Arunachal Pradesh state, Northeast India, collected by members of the Systematics Lab, University of Delhi on 07–09 August 2009. Provisionally referred specimens (see Remarks). One juvenile male (SDBDU 2009.132), and two juvenile females (SDBDU 2009.133 & SDBDU 2009.134), from Pangkava ju (24°40'21.6"N, 94°28'19.86"E, 820 m asl.), Kangpat Khullen, Kamjong sub-division, Ukhrul district, Manipur state, Northeast India, collected by RGK and SDB on 21 May 2009; adult female (CAS 232938 ––tissue only), from Hepu Stream (25°5'25.2"N, 96°24'13.2"E), Hepu village, Moe Nyin township, Myitkyina district, Kachin state, northern Myanmar, collected by G.O.U. Wogan, J.A. Wilkinson, J.V. Vindum, H. Win, T. Thin [“Additional collectors: K.S. Lwin, A.K. Shein and H. Tun ”] on 14 May 2003. Holotype description (measurements in mm). Mature male (SVL 93.8) (Figures 22, & 23A & H). Head moderately large, wider than long (HW 35.0, HL 33.6, IFE 15.5, IBE 25.3); snout bluntly pointed in dorsal view, obtusely protruding beyond mandible in lateral view, without rostral appendage (Figure 22C); loreal region acute, concave; canthus rostralis angular; dorsal surface of snout very slightly concave; eye diameter twice maximum diameter of visible portion of tympanum, and shorter than snout length (EL 10.7, TYD 5.4, SL 11.7); eyetympanum distance (TYE 8.2) less than twice diameter of visible portion of tympanum; tympanum oval-shaped, oblique (Figure 22C), with upper ~15% concealed by supratympanic ridge; pupil vertically elliptical; nostril positioned laterally, closer to eye than to snout (EN 5.2, NS 7.1); internarial distance greater than eyelid width, and equal to narrowest point between upper eyelids (IN 10.5, UEW 8.7, IUE 10.5); pineal ocellus not visible externally; vomerine ridge present, medium sized, ovoid, moderately raised, orientated acutely, positioned between to slightly posterior to choanae, equidistant from choanae and each other; vomerine teeth short; maxillary teeth present; tongue not observed due to fixation of jaw and in interest of preventing potential damage to jaws by forcing open mouth wide enough for examination. Forelimbs long, thin (Figures 22A & B, & 23A), forearm moderately enlarged relative to upper forelimb, and shorter than hand length (FAL 20.6––left side; right side deformed; HAL 24.0); fingers long, narrow, without lateral fringes (Figure 22D), finger length formula IV –75% of the trunk length (Figure 23 A–F); typically only upper border of tympanum is concealed by supratympanic ridge, though up to ~25% of tympanum appears to be concealed on some specimens; parietoscapular-sacral ridge configuration varies considerably amongst individuals, i.e., “>- (”, “>–– |”, “>- <”, or only V-shaped parietoscapular ridge present; coverage of dermal asperities varies mostly in density between individual males in comparison with holotype, however, on some specimens both black (or brown) and white asperities were observed, may sparsely cover upper lips, loreal region, front of snout, posterior dorsal surface of upper eyelids, head, and dorsal surface of tibia-tarsus joints; asperities white on female, restricted to dorsal surface of body, sparse on middorsum, increasing in density posteriorly to above cloaca; outer metacarpal tubercles not visible on most specimens; tubercle cover on flanks varies considerably, some with only sparse scattering of small tubercles, others with moderately dense cover of heterogeneous (large to small) sized tubercles (Figure 23 A–F). Dorsal and ventral markings vary considerably between individuals (see Figure 23 which represent extremes in variation). Secondary sexual characters. Males: nuptial pads present, weakly raised, covered with brown/black microasperities on freshly collected specimens, covering most of dorsal surface of Finger I; nuptial pad on Finger II medium sized, oval, positioned on base of digit on inner dorsal side, extending almost to base of distal phalange; external vocal sac indistinct; large internal vocal slits present on floor of mouth near rear of mandible, on each side; forearms enlarged relative to upper forelimbs. Female: mature ova without pigmented poles; nuptial pads, vocal sac, vocal slits, enlarged forearms, all absent. Morphological comparison. Characters used for comparing Megophrys periosa sp. nov. with its congeners do not include those from the provisionally assigned referred specimens. Megophrys periosa sp. nov. (adult males, N =12, adult female, N =1) differs from M. medogensis, M. zhangi and M. monticola by its larger adult body size, male SVL 71.3–93.8 mm, female SVL 112.0 mm (vs. male SVL 57.2–68.0 mm, N =17; male SVL 32.5–37.2 mm, N =3; male SVL 38.2–49.5 mm, N =17, female SVL 40.5–56.1 mm, N =6, respectively); differs from M. robusta by absence of black dermal asperities on posterior abdomen of adult males (vs. usually present), Finger II<I in length, N =13 (vs. Finger I=II, N =10); differs from Megophrys flavipunctata sp. nov., Megophrys oreocrypta sp. nov., M. major s.s. and M. mangshanensis by absence of distinct white, cream or light coloured stripe along upper lips (vs. present); further differs from Megophrys flavipunctata sp. nov. and M. mangshanensis by its larger adult body size, male SVL 71.3–93.8 mm, female SVL 112.0 mm (vs. male SVL 56.9–68.4 mm, N =4, female SVL 68.0– 74.6 mm, N =3; male SVL 62.5 mm, N =1, female SVL 73 mm, N =1, respectively); further from M. major s.s. by dark spots associated with flank tubercles typically present (vs. absent), toe tips not expanded relative to adjacent toe width (vs. expanded); differs from Megophrys himalayana sp. nov. by its typically larger adult body size, male SVL 71.3–93.8 mm, female SVL 112.0 mm (vs. male SVL 68.0– 73.5 mm, N =7, female SVL 83.9 mm, N =1), typically smaller eye diameter to snout length ratio for males, ED/ES 76.6–91.5%, mean 84.3 ± 4.2% (vs. ED/ES 87.6–101.1%, N =7, mean 94.2 ± 4.6%). Systematic position. This taxon represents M. cf. major 4 (OTU 12) in the molecular analyses, and “ M. cf. major [5]” in Mahony et al. (2017). Megophrys periosa sp. nov. consistently formed a sister taxa relationship with two populations found east of the Brahmaputra River in Manipur and Myanmar referred to herein as Megophrys cf. periosa (M. cf. major 6/OTU 14 in molecular analyses). Uncorrected p -distances for the 16S rRNA gene between Megophrys periosa sp. nov. and M. cf. periosa was 1.6–2.0% (Appendix I, Table 6). The systematic position of this clade within the MMC was not fully resolved (see Systematic position section for Megophrys himalayana sp. nov. for further details), however most analyses placed this species as the sister taxon of Megophrys himalayana sp. nov. (Figures 2 & 4; Appendix I, Table 3; Appendix II, Figures 1, 2 & 5; Mahony et al. 2017). Refer to Appendix I, Table 6 for uncorrected p - distances for the 16S rRNA gene between Megophrys periosa sp. nov. and other MMSG species. Etymology. The species epithet “ periosa ” is a Latinised Greek adjective meaning “immense”, in reference to the very large size that this species attains, even compared to otherwise generally large species in the MMC. Suggested common name: Giant Himalayan Horned Frog. Distribution. Megophrys periosa sp. nov. is so far confirmed from three localities in the state of Arunachal Pradesh, Northeast India. The currently known distribution ranges from East Siang district, west through West Siang district, to at least West Kameng district, between 260 and 1110 m asl. (Figure 8A). An improved and more extensive sampling is necessary to define the east-west limits of this species’ geographic range. Specimens assigned here to Megophrys cf. periosa were collected from Ukhrul district (at 820 m asl.), Manipur state, Northeast India, and from Myitkyina district, Kachin state, northern Myanmar (Figure 8A). Habitat and natural history. All males were in breeding condition, and the female contained well-developed ova within her ovaries, indicative that the breeding season extends at least through late-July and early-August. All specimens were collected after dusk, typically perched on the rocky banks of small to large (1–15 m wide) moderately fast flowing mountain streams flowing through dense mature secondary/primary forest (e.g., Figure 9A & F). Males spaced themselves along the banks of the streams at least 10 m apart. Vocalisations typically consisted of a succession of a few notes followed by an extended silence, but were rarely heard. Healed injuries were observed on two specimens; the right hand of the holotype appears to have been badly dislocated or broken (Figure 22B & E). This large mature male had noticeably less well-developed nuptial pads than the other males, possibly as a result of lower overall fitness, although it otherwise appeared to be in good health. One other specimen (BNHS 6064) had a large swelling on Finger II on the right hand, the cause for which is unclear. Remarks. Specimens reported as M. lateralis and/or M. robusta by Borah and Bordoloi (2001), Bordoloi et al. (2000) and Sarkar and Ray (2006) from Arunachal Pradesh may apply to this species, and/or Megophrys himalayana sp. nov. The specimens reported in these studies should be re-examined to determine the correct identities. Populations provisionally assigned to this taxa (as M. cf. periosa) from eastern Manipur state, Northeast India and northern Myanmar, were found to be the sister taxon to Megophrys periosa sp. nov. (Mahony et al. 2017 [as M. cf. major [6]]; Figures 2, 4 & 5). Regardless of BPP results indicating that this lineage may represent a distinct species-level taxon (Appendix I, Table 5), we recommend that comparable series of adult specimens be studied to further determine the taxonomic status of this lineage. For now, it may provisionally be regarded as conspecific with Megophrys periosa sp. nov.Published as part of Mahony, Stephen, Kamei, Rachunliu G. & Teeling, Emma C., 2018, Cryptic diversity within the Megophrys major species group (Amphibia: Megophryidae) of the Asian Horned Frogs: Phylogenetic perspectives and a taxonomic revision of South Asian taxa, with descriptions of four new species, pp. 1-96 in Zootaxa 4523 (1) on pages 59-63, DOI: 10.11646/zootaxa.4523.1.1, http://zenodo.org/record/261020

A new low altitude species of Megophrys Kuhl and van Hasselt (Amphibia: Megophryidae), from Assam, Northeast India

Mahony, Stephen, Sengupta, Saibal, Kamei, Rachunliu G. (2011): A new low altitude species of Megophrys Kuhl and van Hasselt (Amphibia: Megophryidae), from Assam, Northeast India. Zootaxa 3059: 36-46, DOI: 10.5281/zenodo.27892

Megophrys (Xenophrys) zhangi Ye and Fei 1992

Megophrys (Xenophrys) zhangi Ye and Fei, 1992 (Figure 10) Megophrys zhangi Ye and Fei 1992:50 –52. In: A new pelobatid toad of the genus Megophrys from Xizang, China. Acta Herpetologica Sinica, 1–2: 50–52. Holotype. Adult male (CIB 750296: Figure 10), from “Zhangmo, Nyanang, Xizang altitude 1000 m ” (= Zhangmu town, ~ 27°59'24"N, 85°58'48"E, Nyalam County, Shigatse Prefecture, Tibet [or Xizang] Autonomous Region, China), collected by Yongzu Zhang on 26 June 1975 (Ye & Fei 1992). Paratypes. Two adult males (CIB 750295, CIB 750297), from the “same locality and date as the holotype, altitude 700–1000m ”, collector not mentioned (presumably the same). Examined specimen. Adult male (CIB 750296––photos only), holotype. Description of type series. Refer to Ye and Fei (1992) for the description in Chinese language text. Morphological comparison. Adult body size range provided for Megophrys zhangi is from the original description (Ye & Fei 1992). Megophrys zhangi (adult males, N =3) differs from M. monticola by its smaller adult body size, male SVL 32.5–37.2 mm (vs. adult male SVL 38.2–49.5 mm, N =17); differs from M. mangshanensis by absence of distinct white upper lip stripe (vs. present). For comparisons with subsequent species covered in this paper, refer to relevant morphological comparison sections for those species. Systematic position. Refer to the Systematic position section for Megophrys monticola above. Etymology. The specific epithet “ zhangi ” is a patronym, named for Yongzu Zhang, the collector of the type series. Suggested common name: Zhang’s Horned Frog. Distribution. This species is known with certainty only from the type specimens collected from between 700 and 1000 m elevation, below Zhangmu town (27°59′24″N, 85°58′48″E, 2300 m elevation), Nyalam County, Shigatse Prefecture, Tibet (or Xizang) Autonomous Region (Figure 8A). The proximity of the type locality to the Nepal border suggests that this species will also be found in adjacent areas of central Nepal.Published as part of Mahony, Stephen, Kamei, Rachunliu G. & Teeling, Emma C., 2018, Cryptic diversity within the Megophrys major species group (Amphibia: Megophryidae) of the Asian Horned Frogs: Phylogenetic perspectives and a taxonomic revision of South Asian taxa, with descriptions of four new species, pp. 1-96 in Zootaxa 4523 (1) on page 30, DOI: 10.11646/zootaxa.4523.1.1, http://zenodo.org/record/261020

FIGURE 11 in Cryptic diversity within the Megophrys major species group (Amphibia: Megophryidae) of the Asian Horned Frogs: Phylogenetic perspectives and a taxonomic revision of South Asian taxa, with descriptions of four new species

FIGURE 11. Megophrys robusta lectotype: adult female (BMNH 1947.2.25.19: SVL 102.0 mm) in preservation: A. dorsal view; B. ventral view; C. profile view of head; D. ventral view of foot; E. ventral view of hand

Megophrys (Xenophrys) robusta Boulenger 1908

Megophrys (Xenophrys) robusta Boulenger, 1908 (Figures 11 & 12; Table 1) [?] Xenophrys gigas Jerdon 1870:85 (partim: “ Sikim ”). In: Notes on Indian herpetology. Proceedings of the Asiatic Society of Bengal, March, 1870: 66–85. Megalophrys robusta Boulenger 1908:418, pl. xxiv. In: A revision of the oriental pelobatid batrachians (genus Megalophrys). Proceedings of the Zoological Society of London, 1908: 407–430 + pl. xxii–xxv + fig. 71. Lectotype (by present designation). Adult female (BMNH 1947.2.25.19 [RR 1908.4.8.8]: Figure 11), from “Darjeeling” (~ 27°03'0"N, 88°16'0"E), West Bengal, India, collector J. Gammie, presented by the Indian Museum, collection date unknown. Paralectotypes (by implication). Two adult females (ZSIC 9681, ZSIC 10777), details are the same as for the lectotype. Examined specimens. BMNH 1947.2.25.19 (lectotype: Figure 11); ZSIC 9681, ZSIC 10777 (paralectotypes); three adult males (SDBDU 2011.1057; SDBDU 2011.1062: Figure 12A; SDBDU 2011.1064: Figure 12F), and one adult female (SDBDU 2011.1063: Figure 12C & F), from near Latpanchar town (26°54'34.2"N, 88°23'54.54"E, 1135 m asl.), Kurseong sub-division, Darjeeling district, West Bengal, Northeast India, collected by the Systematics Lab members on 0 5 and 0 6 June 2011; a subadult male (SDBDU 2011.415: Figure 12E), and an adult male (SDBDU 2011.416: Figure 12E), from Stream 1 (26°54'34.7"N, 88°23'52.7"E, 1030 m asl.), Mahananda Wildlife Sanctuary, Latpanchar township, Kurseong sub-division, Darjeeling district, West Bengal, Northeast India, collected by SDB and RGK on 19 and 20 May 2011; two adult males (SDBDU 2009.1270; SDBDU 2009.1284: Figure 12B), and one juvenile (SDBDU 2009.1245: Figure 12D), from Sessa village (27°6'4.02"N, 92°31'38.52"E, 1110 m asl.), West Kameng district, Arunachal Pradesh state, Northeast India, collected by the Systematics Lab members on 07–09 August 2009. Lectotype description (measurements in mm). Mature female (SVL 102.0) (Figure 11). Head large, wider than long (HW 42.0, HL 40.9, IFE 16.9, IBE 30.1); snout broadly pointed in dorsal view, obtusely protruding beyond mandible in lateral view, without rostral appendage (Figure 11C); loreal region acute, concave, with well developed canthus rostralis; dorsal surface of snout concave; eye diameter larger than maximum tympanum diameter, and shorter than snout (EL 11.6, TYD 7.7, SL 13.2); eye–tympanum distance (TYE 8.2) slightly longer than tympanum diameter; tympanum distinctly oval, obliquely orientated (Figure 11C), upper ~40% concealed by supratympanic ridge; pupil indistinct; nostril positioned laterally, circular with raised posterior rim, closer to eye than to snout (EN 5.3, SN 7.4); internarial distance equal to narrowest point between upper eyelids, and greater than upper eyelid width (IN 11.9, IUE 12.0, UEW 10.0); pineal ocellus absent; vomerine ridges well developed, positioned between choanae, closer to choanae than to each other; vomerine teeth absent; maxillary teeth present; tongue large, rounded posteriorly (possibly artefact of preservation), medial lingual process absent. Forelimbs moderately long, thin (Figure 11A & B), forearm slightly enlarged relative to upper forelimb, slightly shorter than hand length (FAL 25.4, HAL 26.3); fingers long, narrow (Figure 11D), finger length formula IV (”, “>--<”, or only V-shaped parietoscapular ridge present; dermal asperities absent on all females and subadults, but all males from Darjeeling possess black spinular asperities in dense thick circummarginal band along lower and upper jaw, covering entire surface below (and including) supratympanic ridges, more sparse on loreal region, absent from front of snout, sparse on posterior surface of upper eyelids, posterior dorsal surface of head and anterior body, increasing in density posteriorly on dorsum, sparse on dorsal and ventral surfaces of thighs, shanks, and tarsi, but more dense on dorsal surfaces near joints, sparse (or occasionally absent) on posterior surface of abdomen, present along all dorsal ridges, absent from flanks, anterior abdomen, chest and throat. Males from Arunachal Pradesh agree with the Darjeeling specimens regarding asperities cover, except that they have less dense asperities on upper jaw, none on supratympanic ridges except on tympanum and surface posterior to tympanum. Some specimens have weakly developed outer metacarpal tubercles visible; moderately well developed thenar tubercles present on some individuals. Flank tuberculation varies from sparse, small tubercles to large, dense tubercles. Dorsal surfaces of snout usually with small irregularly arranged dark brown blotches (Figure 12A, B & D); triangular marking on dorsal surface of head occasionally incomplete; parietoscapular-sacral ridges typically accompanied by dark brown marking that follows shape of dermal ridges, others densely mottled with brown blotches over entire dorsum; general colouration in preservation ranges from pale brown to dark brown dorsally, dorsal marking barely visible (or absent) on darker individuals; some specimens have 3–6 distinct light brown longitudinal stripes extending from gular region onto chest (Figure 12E & F); most have faint to distinct brown blotch extending from posterior border of orbit through tympanum (Figure 12A & B), and from anterior orbit laterally along edge of canthus rostralis to snout tip; all have distinctly dark brown lower edge to supratympanic ridge and brown vertical bars on sides of face, most distinct is broad bar extending from lower border of orbits to edge of upper lip [erroneously reported to be absent in M. robusta by Ohler et al. (2002)] (Figures 11C, & 12A, C & E); outer edge of gular region typically brown, with eight light patches. Secondary sexual characters. Males: nuptial pads present, weakly raised, covered with black microasperities, covering almost entire dorsal surface of Finger I; nuptial pad on Finger II small, oval, positioned on base of digit on inner dorsal side (extending on to base of proximal phalange on some individuals); external vocal sac usually indistinct, though skin is loose on some individuals indicating large sub-gular sac that extends onto chest; large internal vocal slit is present on floor of mouth near rear of mandible on each side; forearms enlarged relative to upper forelimbs. Females: ova not pigmented; nuptial pads, vocal sac, vocal slits, all absent. Morphological comparison. Megophrys robusta (adult males N =6, adult females N =4) differs from M. monticola and M. zhangi by its larger adult body size, male SVL 73.5–83.1 mm, female SVL 81.3–108.3 mm (vs. male SVL 38.2–49.5 mm, N =17, female SVL 40.5–56.1 mm, N =6; male SVL 32.5–37.2 mm, N =3, respectively); differs from M. mangshanensis by absence of distinct white upper lip stripe (vs. present). For comparisons with subsequent species covered in this study, refer to relevant morphological comparison sections for those species. Systematic position. Megophrys robusta was found to be the sister taxon to the MMC clade, and was the second most ancestrally derived lineage in the MMSG after M. monticola (Mahony et al. 2017; Figures 2 & 3; Appendix II, Figures 2, 3A & 4B). The inclusion of additional sequences from Chen et al. (2017) in ML analyses demonstrates that M. robusta is the sister taxon to the morphologically similar M. medogensis, however, the systematic position of this clade was not strongly supported (Figure 4; Appendix II, Figures 5 & 6). Refer to Appendix I, Table 6 for uncorrected p -distances for the 16S rRNA gene between M. robusta and other MMSG species. Etymology. The specific epithet “ robusta ” is Latin for “hard” or “strong”, presumably a reference to the heavy set habitus of this species. Suggested common name: Robust Horned Frog. Distribution. Specimens examined in this study demonstrate that M. robusta ranges at least from the Darjeeling Hills, northern West Bengal state, east through Bhutan to at least the West Kameng district of western Arunachal Pradesh state, in India (Figure 8A). Specimens examined in this study were collected at elevations from 1030 to 1135 m asl. Daniel (1962) reported two specimens (as M. major) collected from Darjeeling itself (~ 2200 m asl.) and from nearby Darjeeling (~ 1675 m asl.), Darjeeling Sadar division, Darjeeling district, West Bengal. Rai and Anders (2002) provided a number of localities in Ilam, Pachthar and Taplejung provinces in eastern-most Nepal (bordering Darjeeling and Sikkim) from 1600 to 2400 m asl., indicating that the Arun River forms the western boundary for the species. They provided a description of M. robusta and figures, which corresponded well with the species as defined here. This species is also found in neighbouring Sikkim state, in Northeast India (Subba et al. 2016; Deuti et al. 2017), and may extend north along river valleys into bordering southern Tibet, China. Refer to the Remarks section for discussions on additional localities published elsewhere. Habitat and natural history. All but one of the specimens collected during this study were collected after dusk from the banks of moderate sized (3–10 m wide), typically shallow rocky hill streams surrounded by at least patches of mature forest, and dense vegetation (Figure 9A). In Darjeeling district during late May to early June, calls provisionally attributed to this species (a loud typical Megophrys (Xenophrys) call) were occasionally heard from streams during both day and night surveys. These calls consisted of a short burst of notes followed by a long silence. At Sessa, similar calls were heard during night surveys in early August, and were used on two occasions to locate individuals. However, in both instances the suspected calling males were found within 1–2 m of a similar sized, and considerably more abundant sympatric MMC species (described below) on the banks of the Sessa River, so calls could not be confirmed to be from M. robusta. At both localities, adult male individuals were always widely dispersed along stream banks and were typically found perched on top of large rocks in the open. A female (SDBDU 2011.1063, SVL 81.3 mm: Figure 12C & F) was collected from a roadside embankment amongst dense vegetation ~ 50 m from the nearest stream. Its ovaries contained small, pigmentless ova. Daniel (1962) reported that a large female (SVL 101 mm) collected in June contained enlarged ova (diameter 2 mm), however, he stated a female specimen (SVL 80 mm) “collected in September had the ovaries dormant”. Though the latter female may have been sexually immature, the available evidence suggests that the breeding season for this species extends at least from mid-May until August. A male specimen (SDBDU 2011.415, SVL 69.1 mm: Figure 12E) collected in late May had distinctly enlarged testes, but had not yet developed nuptial pads and the internal vocal slits were small indicating that this was not yet sexually mature. SDBDU 2009.1284 (SVL 73.5 mm [Figure 12B]) was the smallest sexually mature male. Rai and Anders (2002) provided a number of additional observations that are of interest, however, their description of the call (as “a sharp whistling call, sounding like “ khui-khui ”) does not correspond with the authors’ experience, where calls were distinctly of a lower frequency sound more similar to the “caws” of a crow. Remarks. Boulenger (1908) described this species based on a syntype series of five specimens collected by Dr. J. Gammie from Darjeeling (four in the Indian Museum [now ZSIC], one in the BMNH [now NHMUK]–the figured specimen). He provided measurements of two ZSIC specimens, a female (SVL 114 mm), and a ‘halfgrown’ individual (SVL 54 mm). Dutta (1997) erroneously claimed (and followed by Bordoloi & Borah 2001) that M. robusta was a replacement name for X. gigas Jerdon, 1870 (now M. major). Dutta (1997) also only mentioned ZSIC as the location of type specimens. Chanda et al. (2000), apparently also following Dutta (1997), did not mention M. robusta in the list of type specimens in ZSIC, but instead assigned four specimens (ZSIC 9670, ZSIC 9681, ZSIC 10777, ZSIC 10779) as syntypes of Xenophrys gigas. ZSIC 9681 and ZSIC 10777 clearly represent M. robusta. ZSIC 9670 and ZSIC 10779 were not examined in this study. The ZSIC also recognised (according to a jar label) two additional specimens, ZSIC 9650 (an adult female M. monticola, SVL 51.1 mm) and ZSIC 9668 (not examined in detail but represents either an adult M. monticola or juvenile M. robusta) as ‘types’ of X. gigas. Our study demonstrates that none of these ZSIC specimens are the types of X. gigas (see X. major Remarks section). Thus it remains unclear which four of these six specimens represent the Indian Museum (ZSIC) syntypes mentioned by Boulenger (1908) for M. robusta. For this reason, only BMNH 1908.4.8.8 can currently be verified as a syntype of M. robusta and is therefore designated above as the lectotype of this taxon, thus providing nomenclatural stability by restricting the name to a verified original syntype. Megophrys robusta has been reported from several localities further east in Arunachal Pradesh state, e.g., Lower Subansiri district (Bordoloi et al. 2000; Bordoloi & Borah 2001) and the Upper Siang district and Changlang districts (Pawar & Birand 2001). Pawar and Birand (2001) did not provide a description of the species they observed and did not appear to have collected voucher specimens, so these localities should be considered anecdotal pending collection of verifiable specimens from the Upper Siang and Changlang districts. Several of the morphological characters described by Bordoloi and Borah (2001) indicated that they may have misidentified an MMC species, e.g., “belly with faint darker spots”. They however did not provide further defining and useful taxonomic characters to help identify which species they collected. Therefore, the identities of Bordoloi and Borah’s (2001) specimens require verification before Lower Subansiri district can be included in the verified distribution of M. robusta. Dutta (1997) reported M. robusta from the Garo Hills in Meghalaya state, presumably misidentifying the large unnamed MMC species (formally described below), so this locality also requires verification based on the reexamination of voucher specimens. Sangma and Saikia (2015) provided an account and figure of a specimen they referred to as M. robusta from Tura Peak, West Garo Hills district in Meghalaya state. This specimen clearly possesses a whitish upper lip stripe (absent on M. robusta), demonstrating that it is one of the three MMC species present in Meghalaya. An early report of M. robusta from the East Khasi Hills district, Meghalaya by Hora (1923) was based solely on nondescript tadpoles, and thus this locality should not be included in the species distribution. Khan’s (2008) inclusion of M. robusta on a checklist for Bangladesh (from “NE and N of hills”) herpetofauna is likely erroneous based on geographical distance from verified populations. Furthermore, within the political borders of Bangladesh the maximum elevation barely exceeds 1000 m asl., less than the lowest recorded elevation verified for this species. For the distribution of M. robusta, Sen and Mathew (2008) listed, aside from Arunachal Pradesh state, the Northeast Indian states of Assam, Meghalaya and Nagaland, and the countries of Bangladesh, China (and specifically Hong Kong), Myanmar and Vietnam without accompanying justification, hence these uncorroborated localities are at best considered erroneous.Published as part of Mahony, Stephen, Kamei, Rachunliu G. & Teeling, Emma C., 2018, Cryptic diversity within the Megophrys major species group (Amphibia: Megophryidae) of the Asian Horned Frogs: Phylogenetic perspectives and a taxonomic revision of South Asian taxa, with descriptions of four new species, pp. 1-96 in Zootaxa 4523 (1) on pages 30-37, DOI: 10.11646/zootaxa.4523.1.1, http://zenodo.org/record/261020