Stoliczkia vanhnuailianai, Lalronunga & Lalhmangaiha & Zosangliana & Lalhmingliani & Gower & Das & Deepak, 2021

Lalronunga, Samuel, Lalhmangaiha, K., Zosangliana, Isaac, Lalhmingliani, Esther, Gower, David J., Das, Abhijit & Deepak, V., 2021, A new species of Stoliczkia Jerdon, 1870 (Serpentes: Xenodermidae) from Mizoram India, Zootaxa 4996 (3), pp. 569-580 : 570-574

Stoliczkia vanhnuailianai sp. nov.

( Figs. 1–3 , Table 1)

urn:lsid:zoobank.org:act:30EB2DB5-3519-4EC0-B2DD-A4E6E72402AA

Holotype. BNHS 3656 ( Figs. 1–2 , Table 1), male, Tuinghaleng river near its confluence with Tuirivang river at the vicinity of Phulpui village, Aizawl District, Mizoram, India (23.573°N, 92.756°E, 235 m elevation) by K. Lalhmangaiha and Isaac Zosangliana on 02 March 2021.

Diagnosis and Identification. The new species has the following features, typical of the genus Stoliczkia as reported by Smith (1943): (1) maxillary teeth small and subequal, (2) head very distinct from (much wider than) neck, with large shields, the shields entire or separated by small scales, (3) posterior one-third of the head and temporal region covered with small scales like those of the body, (4) nostril in a large concave nasal, (5) body slender and compressed, and (6) ventrals large.

Stoliczkia vanhnuailianai sp. nov. differs from its congeners in having fewer ventrals (194 versus 207–208 in S. khasiensis and 205–210 in S. borneensis ) and more subcaudals (138 versus 114–115 in male S. khasiensis and 117–124 in male and female S. borneensis ). Stoliczkia vanhnuailianai sp. nov. also differs from S. khasiensis in having more dorsal scale rows at midbody (33 versus 31), and more supraoculars (three versus a single large supraocular). Photographs of the two known specimens of S. khasiensis and a previously published drawing of this species are provided in Figs. 4–6 . Stoliczkia vanhnuailianai sp. nov. also differs from S. borneensis in colour pattern, being distinctly bicoloured with a dark dorsum and pale venter that meet along a regular, straight line, versus having blotches of the pale ventral colour extending dorsolaterally up the flanks and smaller pale blotches middorsally. Stoliczkia vanhnuailianai sp. nov. and S. borneensis possibly also differ taxonomically in infra- and supralabials, dorsal scale rows and subcaudals ( Table 1) but there is only a single specimen of each available for comparison, and/or differences between these two specimens are smaller than between the new species and the two specimens of S. khasiensis ( Table 1), so we do not include those differences in this diagnosis.

Description of the holotype. Specimen in good condition, one longitudinal incision (7.1mm in length) into the coelom ventrally, 114mm from the snout tip. Body elongate, laterally compressed, taller than wide (width 5.5 mm; height 7.9 mm at midbody); head short (4.0% of SVL), broader than tall, much wider than anterior of body. In dorsal view head ovate, sides convex, gently converging anteriorly; front of snout truncated. In lateral view, head flat on top, tapers gently from in front of prefrontal. Paired shields on top of head (internasals, prefrontals, frontals and parietals) abutting along midline rather than overlapping.

Rostral broader (2.0 mm) than tall (1.7 mm), not visible in dorsal view, ventrally with transverse concavity, notched (C-shaped) at margin of mouth. Supralabials (SLs) eight on the left, nine on the right, last supralabial the largest and longest. Each posteriormost supralabial has a faint, narrow, superficial and inconspicuous subvertical groove approximately two thirds of the way back from the anterior tip of the scale—these are not fully formed scale boundaries. The 4 th –6 th SLs on the left and 5 th –7 th SLs on the right contact the spectacle of the corresponding eye. Nasal large, concave and subtriangular with a large laterally placed circular naris ( Fig. 1B ). Internasals small, paired, subequal, subtriangular, left slightly larger than the right. Three small subequal supraoculars, one large pentagonal preocular and three postocular scales on each side. One small, subtriangular loreal on the left and two small loreals on the right. Three ovate temporal scales on each side. Prefrontals large, paired, larger than the paired frontals, subovate with rounded edges, a small ovate scale present between posterior edge of the midline of prefrontal and frontal. Frontal paired, pentagonal, elongated along the posterior edge of the midline; a small subcircular scale present between frontals and their posterior midline in contact with parietals. Parietals largest of head shields, elongate, longer than wide, approximately lanceolate in shape. Scales adjacent to sides and posterior of parietals except temporals are small, similar to body scales behind the head. Lower temporals twice as large as the two above.

Mental small, subtriangular, wider than long. Infralabials 12,12; first pair in midline contact; second and third smallest, tenth and eleventh largest. Four pairs of genials; first pair largest, longer than broad, in long midline contact; second and third pair subequal, in midline contact; fourth pair slightly larger than the preceding two pairs, separated by a scale and in brief contact anteriorly. Anterior genials contact infralabials 1–3; posterior genials separated by 2 or 3 rows of elongate scales. Anteriormost ventral separated from each posterior genial by three scales, separated from posteriormost infralabial by 6 (left) or 7 (right) scales. Teeth largely obscured by gingivae, but estimated as 10 or slightly more marginals on each side of the upper jaw; small and approximately subequal in size.

Macroscopically and under low magnification (using a light dissecting microscope) body scales strongly keeled. Vertebral scale rows not different from adjacent dorsal scale rows. Dorsal scale rows separated by bare skin; scales generally evenly sized on dorsum and along body except for those associated with dorsal scale row reductions, and the three ventralmost rows that are slightly larger. Dorsal scale rows 33 at one head length behind head and at midbody and 27 at one head length before vent.

Ventrals similar in shape throughout, 194 in number. Anal undivided, larger than posteriormost ventrals. Tail subcircular in cross section, flattened ventrally. Dorsal tail scales homogenous in size, smaller than on the body. Subcaudals single throughout, 138 in number, terminal scale (scute) elongate, conical and pointed.

Hemipenis ( Fig. 2G,H ) 9 mm in total length, extending to the posterior of 6 th subcaudal. Bilobed and deeply forked, lobes approximately twice as long as hemipenial body. Lobes slender and cylindrical, bearing low, inconspicuous, ridge-like flounces along their length except for the apex. Hemipenial body without ornamentation. Sulcus spermaticus bifurcate, dividing near but distinctly short of crotch, slightly centrolineal, and extending almost to tips of lobes.

Colour in life ( Fig. 1 ). Dorsum (head, body and tail) predominantly dark brown above, except for the three to four lowermost dorsal scale rows bright yellow. Head scales in dorsal view uniformly dark brown with sutures pinkish in colour; rostral predominantly dark brown. Supralabials mostly yellow but infused with brown along upper margins, cream-yellow below, border between the two colours indistinct. Iris black. Mental and tip of first pair of chin shields yellow and pinkish. Venter yellow on the sides and cream in the middle. Underside of tail darker than the venter of body, brown infused with cream on the anterior half and dark brown on the posterior half.

Colour in preservative ( Fig. 2A–F ). Head dark dorsally, brown-grey, generally uniform, rostral slightly paler. Dark coloration of the upper dorsum extends onto upper margins of the first and last supralabials which are otherwise pale (whitish, as body venter) and immaculate. Dark scales on dorsum (including head) are mottled when viewed under a low-power dissecting microscope. Underside of head pale, whitish. Inside of mouth pale.

Etymology. Named in honour of Vanhnuailiana, a famous Mizo chief and warrior of the Lushai Hills (in present day Mizoram state in India) in the mid 1800s. For nomenclatural purposes, the species epithet is considered a noun in apposition.

Suggested common name. Lushai hills dragon snake (English). In the local Mizo language we suggest the name rulphusin, meaning ‘snake with small scales’, in reference to the presence of small dorsal scales.

Distribution, natural history and conservation. Stoliczkia vanhnuailianai sp. nov. is presently known only from the type locality ( Fig. 3 ). The holotype was spotted on a boulder in a dried up area of a river bed ( Fig. 7 ) at approximately 21:30 on 2nd March 2021.When spotted, the individual was motionless with its head concealed under dry leaves. The area where the holotype was collected is close to the confluence of the river with a larger river. The adjoining fertile floodplain is utilised for agriculture and pisciculture. The collection time coincides with the driest season in Mizoram. The type locality falls within the Tropical Wet Evergreen Forest classification of Singh et al. (2002). The vegetation of the area is mostly dominated by bamboo viz. Dendrocalamus hamiltonii Nees & Arn. ex Munro (family Poaceae ), Bambusa tulda Roxb. (Poaceae) , Melocanna baccifera (Roxb.) Kurz (Poaceae) . Other common trees and shrubs of the area includes Albizia chinensis (Osbeck) Merr. (Fabaceae) , Amomum maximum Roxb. (Zingiberaceae) , Bischofia javanica Blume (Phyllanthaceae) ; Calamus erectus Roxb. (Arecaceae) , Calamus gracilis Roxb. (Arecaceae) , Callicarpa arborea Roxb. (Verbenaceae) , Ficus hirta Vahl. (Moraceae) , Ficus religiosa L. ( Moraceae ), Ficus retusa L. ( Moraceae ), Ficus semicordata Buch. -Ham. ex Sm. ( Moraceae ), Flueggea virosa (Roxb. ex Willd.) Royle (Euphorbiaceae) , Macaranga indica Wight (Euphorbiaceae) , Mangifera indica L. ( Anacardiaceae ), Musa spp. (Musaceae) , Pandanus odorifer (Forssk.) Kuntze (Pandanaceae) , Parkia timoriana (DC) Merr. (Fabaceae) , Psidium guajava L. ( Myrtaceae ), Toona ciliata M. Roem. (Meliaceae) , Trema orientalis (L.) Blume ( Cannabaceae ).

Other reptiles broadly sympatric with the new species include the snakes Ahaetulla prasina (Boie, 1827) , Coelognathus radiatus (Boie, 1827) , Dendrelaphis pictus (Gmelin, 1789) , Fowlea piscator (Schneider, 1799) , Herpetoreas xenura (Wall, 1907) , Lycodon zawi Slowinski, Pawar, Win, Thin, Gyi, Oo & Tun, 2001 , Naja kaouthia Lesson, 1831 , Ptyas korros (Schlegel, 1837) , and Trimeresurus erythrurus (Cantor, 1839) , and the lizards Calotes emma Gray, 1845 , C. versicolor (Daudin, 1802) , and Sphenomorphus sp. Amphibians found in this area include the frogs Amolops indoburmanensis Dever, Fuiten, Konu & Wilkinson, 2012 , Euphlyctis kalasgramensis Howlader, Nair, Gopalan & Merilä, 2015 , Ingerana borealis (Annandale, 1912) , Microhyla berdmorei (Blyth, 1856) , Odorrana chloronota (Günther, 1876) , Minervarya asmati (Howlader, 2011) , Pterorana khare Kiyasetuo & Khare, 1986 , Raorchestes sp. , Sylvirana lacrima Sheridan & Stuart, 2018 , Xenophrys major (Boulenger, 1908) , and X. serchhipii Mathew & Sen, 2007 .

Stoliczkia vanhnuailianai sp. nov. is known only from a single specimen at a point locality, such that next to nothing is known of its distributional range or ecological preferences or tolerances. In addition, species of this genus are clearly rarely encountered. Thus, it is not currently possible to assess the conservation status of this species. At the type locality there is small-scale agricultural and piscicultural practice by the local communities. Numerous patches of forests are cleared for shifting cultivation which could be a threat if this species is a narrowly distributed habitat specialist.

Figures

FIGURE 1. Stoliczkia vanhnuailianai sp. nov. holotype (BNHS 3656) in life. A. dorsolateral body, B. lateral of head and C dorsal of head. Images not to same scale; measurements are reported in Table 1.

FIGURE 2. Stoliczkia vanhnuailianai sp. nov. holotype (BNHS 3656), Body: A. dorsal, B. ventral; head: C. dorsal, D. ventral, E. lateral right, F. lateral left view, G. asulcate and H. sulcate view of left hemipenis. Scale bars 5 mm.

FIGURE 3. Maps showing distribution of species of the genus Stoliczkia. The type of S. khasiensis is from the Khasia (or Khassia or Khasi) Hills without a precise locality. For S. borneensis only the type locality is indicated. Map created using QGIS.

FIGURE 4. Holotype of Stoliczkia khasiensis BMNH 1946.1.15.58. Body in A. dorsal and B. ventral views. Head in C. dorsal, D. ventral, E. lateral left, and F. lateral right views. Scale bars 5 mm. Photographs by Kevin Webb (NHM, London).

FIGURE 5. Second and only known non-type specimen of Stoliczkia khasiensis (ZSI-K 14945) reported by Annandale (1904). Body in A. dorsal, and B. ventral views. Head in: C. dorsal, D. ventral, E. left lateral left, and F. right lateral views. Scale bars = 5 mm. Photographs by Pratyush Mohapatra (ZSI-K).

FIGURE 6. Drawing of Stoliczkia khasiensis (ZSI-K 14945), plate reproduced from Annandale (1904).

FIGURE 7. Habitat of Stoliczkia vanhnuailianai sp. nov. A. exact location where the holotype was found, and B. general surrounding habitat.