Megophrys (Xenophrys) serchhipii ( Mathew & Sen, 2007 )

Mahony, Stephen, Kamei, Rachunliu G., Teeling, Emma C. & Biju, S. D., 2020, Taxonomic review of the Asian Horned Frogs (Amphibia: Megophrys Kuhl & Van Hasselt) of Northeast India and Bangladesh previously misidentified as M. parva (Boulenger), with descriptions of three new species, Journal of Natural History 54 (1 - 4), pp. 119-194 : 166-175

Megophrys (Xenophrys) serchhipii ( Mathew & Sen, 2007)

Xenophrys serchhipii Mathew and Sen, 2007, p. 21 , In: Description of two new species of Xenophrys ( Amphibia : Anura : Megophryidae ) from north-east India. Cobra , 1(2), 18 – 28.

Holotype. Maturity and sex not given ( V /A/ERS/ ZSI/773 [ Figure 13 ]) from ‘ INDIA: Mizoram, Serchhip district, Serchhip, Agriculture Guest House compound (N. 23° 20 ′ 31.6 ″, E. 92° 50? ’

46.6 ″, Alt. 880 m above msl. ’, collected by Rosamma Mathew [‘ and party ’ according to Mathew and Sen 2009] on 23 September 2005 ( Mathew and Sen 2007, fig. 12).

Referred specimens. Three adult males ( SDBDU 2011.464 [ Figure 14 (e)] – 2011.466) and a juvenile ( SDBDU 2011.463) from Tura peak (25.504611, 90.231278, 765 m asl.), near Tura town, West Garo Hills district, Meghalaya state, NEI, collected by RGK on 1 July 2011; two juveniles ( SDBDU 2009.1109 & SDBDU 2009.1110) and a metamorph ( SDBDU 2009.1161) from Tura Peak (25.508167, 90.229117, 640 m asl.), near Tura town, West Garo Hills district, Meghalaya state, NEI, collected by Systematics Lab members between 20 – 25 June 2009; adult male ( SDBDU 2009.580 [ Figure 14 (c,d)]) from Gumti Wildlife Sanctuary (23.410567, 91.790217, 85 m asl.), Karbook division, Gomati district, Tripura state, NEI, collected by Systematics Lab members on 7 July 2009; six adult males ( SDBDU 2009.612 – 614, SDBDU 2009.635 – 637) from below Eden Tourist Lodge (24.003633, 92.280167, 525 m asl.), Vanghmun village, Jampui Hills, Kanchanpur division, North Tripura district, Tripura state, NEI, collected by Systematics Lab members on 8 – 9 July 2009; a metamorph ( SDBDU 2009.674) from Phuldungsei (23.817567, 92.261883, 780 m asl.), Jampui Hills, Kanchanpur division, North Tripura district, Tripura state, NEI, collected by RGK on 11 July 2009; two adult males ( CES 19912 [field tag RGK 0074] & CES 19913 [field tag RGK 0075]) from a stream on National Highway 39 (24.817500, 93.550278, 400 m asl.), Luangchum village, Tamenglong district, Manipur state, NEI, collected by RGK on 24 May 2013; three adult males ( CES 19914 – 19916 [field tags RGK 0085 – 0087]) from Mpeihbak duithuak (24.850000, 93.623055, 450 m asl.), Khumhzi village, Tamenglong district, Manipur state, NEI, collected by RGK on 26 May 2013; adult male ( SDBDU 2008.1492) from Bihpang rang (25.026389, 93.414167, 925 m asl.), Aziuram village, Tamenglong district, Manipur state, NEI, collected by SDB and RGK on 3 June 2008; adult male ( SDBDU 2008.1451) from Duidip chaengluang (24.932778, 93.403889, 210 m asl.), Bamgaizaeng village, Tamenglong subdivision, Tamenglong district, Manipur state, NEI, collected by SDB and RGK on 29 May 2008; adult male ( SDBDU 2008.1517 [ Figure 14 (a,b)]) from Luangmai village Part II (24.837222, 93.403889, 815 m asl.), Tamenglong district, Manipur state, NEI, collected by SDB and RGK on 7 June 2008; two adult males ( SDBDU 2007.220 & SDBDU 2007.221) from New Sendenyu Village (25.920555, 94.108889, 880 m asl.), Tseminyu circle, Kohima district, Nagaland state, NEI, collected by RGK on 2 October 2007; adult female ( SDBDU 2007.238) and a juvenile ( SDBDU 2007.239) from the Akerü River (25.917778, 94.090000, 510 m asl.), Kenrunhü, New Sendenyu Village, Tseminyu circle, Kohima district, Nagaland state, NEI, collected by RGK on 3 October 2007; adult male ( SDBDU 2007.046) from Vibalieza (25.709722, 94.053611, 810 m asl.), Sechu village, Sechu-Zubza circle, Kohima district, Nagaland state, NEI, collected by RGK and VK on 12 June 2007; four adult males ( ZSI 9696, ZSI 9697, ZSI 9711, & BMNH 1908.4.8.1 [ex. ZSI 9704]) and an adult female ( BMNH 1908.4.8.2 [ex. ZSI 9699] [ Figure S4 (a,b)]) from ‘ Cherrapunji ’ [or Sohra], East Khasi Hills district, Meghalaya state, NEI, collected by J.H. Bourne; adult female ( BMNH [18]72.4.17B) and two adult males ( BMNH [18]72.4.17D & BMNH [18]72.4.17F) from ‘ Sikkim ’ [corrected here to Khasi Hills, Meghalaya state], NEI, collected by T.C. Jerdon ca. 1870; adult female ( BMNH [18]72.4.17L) and five adult males ( BMNH [18]72.4.17H & BMNH [18]72.4.17M – P [ Figure S4 (a,b)]) from ‘ Darjeeling ’ [corrected here to Khasi Hills, Meghalaya state], NEI, collected by T.C. Jerdon ca. 1870; adult female (JU 0042 [ Figure 14 (f)]) and two adult males (JU 0043 & JU 0044) from Hillside Resort compound (ca. 22.168320, 92.223140, 150 m asl.), Milonchhori, Bandarban district, Chittagong Hill Tracts, Chittagong division, southeast Bangladesh, collected by SM between 17 – 20 July 2006 ( Mahony and Ali Reza 2008).

Description of referred specimen SDBDU 2011.464 (measurements in mm). Mature male (SVL 41.0) ( Figure 14 (e)). Head moderately large, as wide as long (HW 15.5, HL 15.4, IFE 7.2, IBE 12.4); snout rounded in dorsal view, obtusely protruding in lateral view, rostral appendage absent ( Figure 14 (e)); loreal region vertical and concave; canthus rostralis blunt; dorsal region of snout slightly concave; eye twice as long as maximum tympanum diameter, and shorter than snout (EL 5.5, TYD 2.8, SL 6.0); eye – tympanum distance (TYE

2.8) equal to maximum tympanum diameter; tympanum oval, with upper margin concealed by supratympanic ridge; pupil in life diamond shaped, vertically orientated when contracted; nostril oval, positioned laterally, situated closer to eye than to snout (EN 2.7, SN 3.3); internarial distance subequal to maximum upper eyelid width, and slightly wider than narrowest point between upper eyelids (IN 4.4, UEW 4.3, IUE 4.2); pineal ocellus not visible externally; vomerine ridges round, moderately raised, positioned slightly posterior to choanae, closer to each other than to choanae; vomerine teeth very small; maxillary teeth present; tongue not observed.

Forelimbs moderately long, thick ( Figure 14 (e)); forearms slightly enlarged relative to upper forelimbs, forearm shorter than hand length (FAL 9.5, HAL 11.1); fingers short, not dorsoventrally flattened, lateral fringes absent, finger length formula IV <I = II <III (FIL 5.0, FIIL 5.0, FIIIL 7.4, FIVL 4.4); interdigital webbing, subarticular and supernumerary tubercles absent; thenar tubercles distinct; outer metacarpal tubercles barely distinguishable; fingertips not expanded, distinct pads absent, terminal grooves on fingertips absent. Hindlimbs relatively long, moderately thick; thigh equal to shank length, and longer than foot (TL 19.6, SHL 19.6, FOL 17.7); toes short, rounded, lateral fringes absent, relative toe lengths I <II <V <III <IV; toe tips not dilated, distinct longitudinally oval pads present, terminal groves on toe tips absent; base of toes with rudimentary webbing; outer metatarsal tubercle, subarticular and supernumerary tubercles absent; inner metatarsal tubercle present but barely distinguishable; ridge of callous tissue present on ventral surface of all toes.

Skin of dorsal surfaces of head, body and limbs smooth to rugose with small weak granular tubercles ( Figure 14 (e)); flanks, dorsum and limbs with larger scattered tubercles and short ridges ( Figure 14 (e)); tympanum smooth, flat, surrounding area posterior to eye weakly granular; small tubercular ridge present on outer edge of upper eyelids; supratympanic ridge narrow anteriorly, moderately wide posteriorly, extending from orbit in a straight line to upper tympanum border, broadly curving obliquely downward along posterior border of tympanum, terminating above shoulder ( Figure 14 (e)); dorsolateral ridges absent; well developed ‘ \ / ’ -shaped parietoscapular ridge and unconnected inverted ‘ V ’ -shaped sacral ridge present; additional oblique fold on dorsum artefact of preservation; ventral surface of head and body primarily smooth anteriorly with small and scattered granular tubercles, granular tubercles increase in density posteriorly over abdomen; ventral surfaces of limbs primarily smooth with small and scattered granular tubercles; pectoral and femoral glands moderately well developed, weakly tubercular. Dermal asperities present on cloacal region and dorsal surfaces of hind limbs, otherwise absent from other surfaces.

Colour: In preservation: Dorsal and lateral surfaces of head and body mottled light and dark brownish-grey; solid dark brown thick ‘ Y ’ -shaped marking on dorsal surface of head; apex of dorsal and flank ridges and tubercles light grey, most bordered laterally/ventrally with dark brown spot; front of snout and lateral canthus rostralis primarily dark brown; wide vertical dark brown bar below eyes; dark brown blotch extends from posterior canthus, through tympanum to posterior supratympanic ridge on each side; supratympanic ridges light grey dorsally, dark brown ventrally; dorsal surfaces of upper forelimbs primarily light greyish-brown, forearms and hindlimbs mottled light and dark greyish-brown; dorsal surface of outer three fingers with dark brown blotches; lateral surfaces of thighs and shanks with dark brown spots and blotches. Throat primarily mid-greyish-brown, fading posteriorly on abdomen to primarily pale grey, large brown spots/blotches present on throat, chest and abdomen; ventral surfaces of forelimbs, thighs and shanks mottled pale yellowish-brown and dark brown; area surrounding vent and posterior surfaces of thighs dark brown; ventral surfaces of tarsus and feet dark brown with contrasting light grey callous ridges on toes; light grey inner metatarsal tubercle; hands ventrally brown with ventral surfaces of digits light grey; pectoral and femoral glands creamish-white. In life ( Figure 14 (e)): Markings same as in preservation except colouration less grey and more richer shades of brown; most granular tubercles, and tips of larger tubercles on dorsal surface bright orange; pupil with light circummarginal ring, otherwise iris light grey with darker stripes radiating from outer edges of pupil.

Variation. See Table 2 for morphometric characters of 25 adult males, four adult females and five juveniles. Other referred specimens agree with that described above in general morphology, with the following exceptions: shanks typically slightly longer than thighs; vomerine ridges positioned between to slightly posterior to choanae on some individuals, can be as close to each other as they are to choanae; vomerine teeth can be very small to moderately long, or absent on many individuals; posterior edge of tongue is typically weakly bifurcate, though this bifurcation is not obvious on some specimens presumably due to fixation (or an artefact of preservation); medial lingual process on tongue always absent (tongue not observed in holotype); supratympanic ridge typically conceals upper border to ~10% of tympanum; outer upper eyelids can have a short transverse dermal ridge, a small tubercle, or neither a ridge nor tubercle; pectoral and femoral glands may be small to moderately large in diameter, and can appear flat or weakly raised on specimens in preservation; parietoscapular-sacral ridges, when present, vary considerably between individuals, with the following configurations observed: ‘ \ / ’ -shaped or ‘ \_/ ’ -shaped parietoscapular ridge only; complete or incomplete ‘ V ’ -shaped or ‘ U ’ -shaped parietoscapular ridge only; both ‘ V ’ -shaped parietoscapular ridge and inverted ‘ U ’ -shaped sacral ridge; white and/or black dermal asperities coverage on males varies by individual, and may be present or absent on the following surfaces: laterally at rear of jaw, circummarginally along lower jaw, on posterior upper eyelids, on tympanum, dorsal surfaces of hind limbs, and posterior dorsum; dorsal and lateral surfaces of head, body and limbs on many specimens are encrusted with tiny microasperities; dermal asperities were not observed on females and old museum specimens (presumably an artefact of preservation for old specimens); thenar tubercles may be weak to moderately well developed; digit tips appear slightly expanded on many specimens; extent of dorsal and lateral tubercles and short ridges on body and limbs varies extensively by individual; approximately half of specimens examined from ‘ Cherrapunji ’ (Sohra) area have short dorsolateral ridges anteriorly which range in length from ~5 – 40% of trunk length (e.g. Figure S4 (a)), specimens from other localities typically have no dorsolateral ridges ( Figures 13 and 14 ). Colouration and markings vary considerably between individuals ( Figure 14 ); iris is generally pale brown with dense dark brown radiating venous lines in most populations ( Figure 14 (a,c,e)) but appears distinctly more golden in the Bangladesh individuals observed ( Figure 14 (f)).

Secondary sexual characters. Males: nuptial pads slightly raised covered with black micro-asperities, covering most of dorsal surface of base of Finger I, narrowing distally,

extending to base of distal phalange on inner dorsal side; on Finger II, nuptial pad small, oval shaped, on inner dorsal side of base of digit extending to mid-proximal phalange on some specimens; external vocal sac distinct on some specimens as loose skin, forms large single subgular sac that extends onto anterior chest when fully inflated; internal vocal slit present on floor of mouth, near rear of lower mandible on both sides; forearms slightly to moderately enlarged relative to upper forelimbs; dermal asperities typically present on all recently preserved specimens; fleshy projection above cloaca absent. Females: lack nuptial pads, external vocal sac, internal vocal slits, enlarged forearms and dermal asperities; ova are unpigmented.

Morphological comparisons. Megophrys serchhipii (adult males, N = 25; adult females, N = 4) differs from the following species that have not yet been assigned to a subgenus or species group through molecular analyses: from M. damrei and M. shuichengensis by smaller adult size, male SVL 36.1 – 46.7 mm, female SVL 46.1 – 53.0 mm (vs. M. damrei : adult male SVL 47.7 – 57.1 mm, N = 7, adult female SVL 69.1 mm, N = 1 [Mahony 2011; Neang et al. 2013]; M. shuichengensis : adult male SVL 102.0 – 118.3 mm, N = 8, adult female SVL 99.8 – 115.6 mm, N = 7 [ Tian et al. 2000]); from M. feii by larger adult size, male SVL 36.1 – 46.7 mm, female SVL 46.1 – 53.0 mm (vs. adult male SVL 24.3 – 25.1 mm, N = 4, adult female SVL 28.2 – 28.9 mm, N = 2), lateral dermal fringes on toes absent (vs. present), and nuptial pads on fingers of males present (vs. absent) ( Yang et al. 2018).

Megophrys serchhipii differs from M. parva s.s. by larger adult size, male SVL 36.1 – 46.7 mm, female SVL 46.1 – 53.0 mm (vs. male SVL 33.9 – 36.0 mm, N = 2, female SVL 41.1 – 41.4 mm, N = 2), by dorsolateral ridges typically absent, or short if present, extending <40% trunk length (vs. present, from ~70% to complete trunk length), and FIVL<FIL (vs. FIL<FIVL).

Megophrys serchhipii differs from all species molecularly assigned to the M. (X.) megacephala SG based on the following characters: from M. ancrae by dorsolateral ridges absent or short if present, extending <40% trunk length (vs. always present, usually between ~65% to complete trunk length); from its morphologically most similar congener M. megacephala by typically narrower relative head width on adults, HW/ SVL 33.4 – 40.4 %, N = 28 (vs. HW/ SVL 40.2 – 45.1 %, N = 12), typically smaller adult male size, SVL 36.1 – 46.7 mm (vs. 45.9 – 53.4 mm, N = 7), FIL = FIIL (vs. FIIL<FIL); from M. oropedion by dorsolateral ridges absent, or short if present, extending <40% trunk length (vs. always present, approximately 75% trunk length), palmar tubercles absent on 25/ 28 specimens (vs. distinct, weakly developed on 8/ 10 specimens).

Refer to the ‘ Morphological comparison ’ sections of Megophrys dzukou sp. nov., Megophrys awuh sp. nov., Megophrys numhbumaeng sp. nov., and M. zunhebotoensis for diagnostic characters.

Etymology. According to Mathew and Sen (2007), the specific epithet ‘serchhipii’ is a toponym after the locality where the holotype specimen was collected, but it is unclear how the name was coined. If the locality name was to be treated as a noun in apposition, it would be given as ‘serchhip’, otherwise a typical genitive termination for this toponym would be -ensis (e.g. ‘serchhipensis’ meaning ‘ from Serchhip ’). However, the suffix -i or -ii are typically used in cases of names formed from personal names. The locality name, Serchhip, means ‘ citrus[trees]-on-top [of the first hill of the then Serchhip village, which now included New Serchhip and Chhiahtlang villages] ’, and so the specific epithet spelling appears to be a case of incorrect Latinisation. Since it is essentially without meaning, the name falls within the category of an ‘ arbitrary combination of letters ’ (ICZN 1999: Article 11.3). In any case, the original spelling cannot be emended to correspond with its originally proposed etymology (e.g. to ‘serchhipensis’), and must be retained as the ‘ correct original spelling ’ according to the Code (ICZN 1999: Articles 11.3 & 32.5.1).

Suggested common name. The previously suggested common names ‘ Serchhipii Horned Frog ’ Dinesh et al. (2009) and ‘ Serchhip ’ s Horned Toad ’ ( Mathew and Sen 2010) are based either on an arbitrary combination of letters (i.e. ‘ Serchhipii ’), or confusingly indicate that the name might be based on a genitive, as the spelling of the species epithet suggests (see ‘ Etymology ’ section above). To avoid such confusion, we suggest ‘ Common Warty Horned Frog ’ as a suitable and simple alternative common name for this species since it is widespread in northeast India south/east of the Brahmaputra River and is so far the only Megophrys species confirmed from Bangladesh. It is also the most tuberculate (or ‘ warty ’) species found in the region.

Distribution. Until this study, Megophrys serchhipii was known only from the type locality in Serchhip district, Mizoram state, NEI. It is now found to be the most widely distributed small-sized Megophrys in the region, found between 85 and 925 m asl. In NEI, it is found from the West Garo Hills district, Meghalaya, in the west, east along the southern foothills of the Shillong Plateau, into Kohima district in southern Nagaland state in the north, south through Manipur and Tripura states, into Mizoram state and the adjacent Chittagong Hill Tracts of southeastern Bangladesh ( Figure 2 ). Though not yet recorded, it is likely to be found in hilly areas of southern Assam and adjacent areas of southwestern Myanmar at similar elevations. The localities ‘ Sikkim ’ and ‘ Darjeeling ’ associated with Jerdon ’ s NHMUK collections are considered erroneous.

Habitat and natural history. Calling males were all found on the banks of small, shallow rocky hill streams, typically perched on rocks, leaf litter, or on low vegetation on stream banks, or overhanging a stream. Males of this species have been observed to be territorial, approaching a dictaphone during playback of an advertisement call recording, producing a different, more vigorous call ( Mahony and Ali Reza 2008). Calling has been heard from early June to early October and heavily gravid females (not collected) were observed between July end and early September indicating an extended breeding period throughout the monsoon and post-monsoon. Tadpoles were collected from Vanghmun, Tripura (present study) and Bandarban, Bangladesh ( Mahony and Ali Reza 2008) during the first two weeks of July. Metamorphs have been found during late June and early July. Juveniles of varying sizes were typically found away from streams among leaf litter. This species has been collected from a variety of habitats, from heavily disturbed habitats, mostly cleared of forest cover except a narrow strip of dense vegetation along a stream (in Bangladesh; Mahony and Ali Reza 2008), to dense bamboo groves, and mature monoculture teak plantations (Tripura state), and low to mid-elevation tropical evergreen and semideciduous broadleaf forest with varying degrees of anthropogenic disturbance (elsewhere in NEI).

Remarks. Mathew and Sen (2007) described Megophrys serchhipii based on a single specimen for which they neither identified the sex, nor the maturity. The original description did not mention diagnostic morphological characters that distinguished this species from its then known congeners. The authors ambiguously claimed that it was most closely related to M. wuliangshanensis Ye and Fei, 1995 (based on a specimen presumably from NEI, although no locality or specimen number was provided — see the section titled ‘ On the status of Megophrys (Panophrys) wuliangshanensis reported from India ’ for discussion regarding Indian populations of M. ‘wuliangshanensis’). The holotype of Megophrys serchhipii was then only compared to this one specimen of M. ‘wuliangshanensis’ (but not the species as described by Ye and Fei 1995), from which it was unsurprisingly found to differ in morphometric measurements. In the absence of a meaningful taxonomic description, comparison with congeners, or identification of the sex and sexual maturity of the specimen, Megophrys serchhipii remained a taxonomic enigma. Though the holotype was not examined in detail in this study, photographs (by SDB; Figure 13 ) demonstrated that this specimen is morphologically indistinguishable from additional collections and populations of the widespread low to mid-elevation Megophrys species from NEI. The holotype does not have obvious male secondary sexual characters, e.g. nuptial pads and enlarged forearms relative to upper arms, demonstrating that the specimen is either an immature male or a female. Direct examination of gonads would be required to confirm the sex of the specimen in question. Mathew and Sen (2009) provided low-resolution colour images of the holotype, and Mathew and Sen (2010) provided two photographs of Megophrys serchhipii in life. Considering that the species was known only from a single specimen, presumably the photos in Mathew and Sen (2009, 2010) are of the holotype.

The wide geographic distribution of this species in NEI including the colonial hill station of Sohra (Cherrapunji) ensured its presence in the collections of the NHMUK and ZSI, where it was historically misidentified as Megophrys monticola (e.g. Jerdon 1870; Anderson 1871; Boulenger 1882, 1890, 1908; Sclater 1892) and later as Megophrys parva (e.g. Boulenger 1908). Most recently, Deuti et al. (2017) provisionally regarded some of these specimens (e.g. the BMNH [18]72.4.17 [e.g. Figure S4 (c,d)] series [see also Taxonomic accounts section], BMNH 1908.4.8.1, BMNH 1908.4.8.2 ( Figure S4 (a,b)), ZSI 9696, ZSI 9697, ZSI 9711, and presumably others) to be conspecific with M. parva s.s., an opinion which we do not share (see Morphological comparison section above). Jerdon ’ s collections of this species deposited in the BMNH (BMNH [18]72.4.17A – Q) from ‘ Sikkim ’ and ‘ Darjeeling ’ are presumed to have been mislabelled (see Taxonomic accounts section), therefore Sikkim and West Bengal states should not be included in the species ’ geographic range until specimens with verifiable locality data are found. Saikia and Sen (2012) and Kharkongor et al. (2018) reported this species from Mawmluh/Mawbah (N 25°13 ′ 54 ″, E 91°41 ′ 0.8 ″, 739 m asl.) near Sohra (as ‘ Cherrapunjee ’), East Khasi Hills district, Meghalaya as ‘ Xenophrys zunhebotoensis’ (see below ‘ Remarks ’ section for M. zunhebotoensis ).

Megophrys serchhipii has been reported from Bangladesh in the following papers: Mahony and Reza (2008; as ‘ Xenophrys cf. parva’) followed by Reza and Perry (2015; as ‘ Xenophrys parva’) from Bandarban, southeastern Bangladesh, who provided behaviour and habitat observations of adults and tadpoles; Asmat (2009) and IUCN Bangladesh (2015) provided figures depicting M. serchhipii (as ‘ Xenophrys parva’) from unspecified localities, reporting it from Rangamati, Bandarban and Khagrachari Hill districts, and Greater Sylhet in eastern Bangladesh. IUCN Bangladesh (2015) regarded the species to be ‘ Near Threatened ’ in Bangladesh. Specimens (if collected) of ‘ Xenophrys parva’ reported by Hasan and Feeroz (2014) from Dudpukuria-Dhopachari Wildlife Sanctuary and Teknaf Wildlife Sanctuary in southeastern Bangladesh require re-examination to confirm their identity. Hasan et al. (2014) provided figures depicting M. serchhipii (as ‘ Xenophrys parva’) and a brief account and distribution for the Bangladesh populations.

The systematic position of Megophrys serchhipii relative to other members of the M. (X.) megacephala SG is currently unresolved. Molecular phylogenetic analyses that include mtDNA place M. serchhipii as the sister taxon to a clade comprising Megophrys awuh sp. nov. and M. zunhebotoensis with low (56% bs. in the mtDNA only tree [ Figure S1 ]) to high (100% bs. in the mt+nuDNA tree [ Figure 1 ]) support. Analyses including nuDNA only resolved this species to be the sister taxon to a clade comprising all remaining M. (X.) megacephala SG members bar M. megacephala with high support (98% bs.), however, relationships within this clade are unresolved ( Figure S2 ).

Figures

Figure 1. ML phylogenetic tree of the subgenus Megophrys (Xenophrys) based on the concatenated mt +nuDNA alignment. Bootstrap values ≥95% are represented by a black spot; 80–95% represented by a grey spot; <80% not given. Numbers next to species names correspond with specimen numbers in Table 1.

Figure 2. Topographic distribution map of the Megophrys (X.) megacephala SG taxa: Left. All taxa from Northeast India and surrounding countries: diamonds represent type localities; circles represent referred localities based on examined specimens; circles with central dot represent identifications based on literature where sufficient evidence was available (see Remarks sections); Right. Inset rectangle enlarged to show the distributions of species from more densely sampled southern Nagaland and northern Manipur states, Northeast India. Blue lines represent major rivers; grey lines represent international borders.

Figure 4. Megophrys ancrae referred specimens from Changlang district, Arunachal Pradesh state, India: (a). adult male (SDBDU 2009.727: SVL 42.5 mm) in life; (b). adult male (SDBDU 2009.730: SVL 43.0 mm) in life; (c). adult male (SDBDU 2009.727) in preservation, ventral view showing hands with expanded digit tips; (d). adult males (SDBDU 2009.727, left & SDBDU 2009.730, right) in preservation, ventral view showing variation in markings.

Figure 13. Megophrys serchhipii, maturity and sex unknown, holotype (ZSI/ERS V/A/773: SVL 37.0 mm: Mathew and Sen 2007) in preservation, from Serchhip district, Mizoram state, India: (a). dorsal view; (b). ventral view; (c). profile view of head; (d). ventral view of hand; (e). ventral view of foot.

Figure 14. Megophrys serchhipii referred specimens showing variation in life: (a–b). adult male (SDBDU 2007.1517: SVL 41.3 mm) from Tamenglong district, Manipur state, India: (a). dorsolateral view; (b). ventral view; (c–d). adult male (SDBDU 2009.580: SVL 45.1 mm) from Gomati district, Tripura state, India: (c). dorsolateral view; (d). ventral view; (e). adult male (SDBDU 2011.464: SVL 41.0 mm) from West Garo Hills district, Meghalaya state, India, lateral view; (f). adult female (JU 0042: SVL 53.6 mm) from Chittagong division, Bangladesh, lateral view.