Gloydius nepalensis sp. nov.

Common names.

Nepali Pitviper (English), Andho sarpa and Bhyagute sarpa (Nepali, according to Shah and Tiwari 2004; Sharma et al. 2013).

Type material.

Holotype. • ZMB 65613, an adult male from Kalopani village, Mustang District, Gandaki Province, Nepal, 28.6167°N, 83.6000°E, 2500 m altitude, donated by Matthias Lorenz (Fig. 21). Paratypes. • BMNH 1953.1.1.71, juvenile female collected 8 miles west of Tibrikot, Dolpa District, Karnali Province, Nepal by William Russell Sykes in 1952; MHNG 1329.6 and MHNG 1329.8, male and female from Dhorpatan, Baglung District, Gandaki Province, Nepal, collected by L. Naef in September 1963 and R. Weiersmüller in October 1963 respectively; NME R 0544 / 07 (field no. SN 6500), adult male from Kermi, 14 km northwest of Simikot, Humla District, Karnali Province, Nepal, collected on 12 June 2001 by Jörg Weipert; NHMK 254 (formerly RMNH.RENA 20514), adult male from Gurja Ghat, 5 km east of Dhorpatan, Baglung District, Gandaki Province, Nepal, collected on 14 July 1981 by Paul E. Ouboter, Lurly M. R. Nanhoe and Karan B. Shah; RMNH.RENA.20512, adult male from Tal village, Manang District, Gandaki Province, Nepal, collected on 3 May 1981 by Lurly M. R. Nanhoe and Paul E. Ouboter; RMNH.RENA.20513, adult female from Dhorpatan, Baglung District, Gandaki Province, Nepal, collected on 13 July 1981 by Lurly M. R. Nanhoe and Paul E. Ouboter; ZMB 65612, adult female from Syang village (Jomsom) Mustang District, Gandaki Province, Nepal, donated by Matthias Lorenz; ZSM 154/1973/1 –2, adult male and female, ZSM 154/1973/4, adult male, and ZSM 156/1973/1, adult male, all from Kalopani village, Mustang District, Gandaki Province, Nepal, collected on 8 June 1973 by Ulrich Gruber and Dieter Fuchs; ZSM 157 / 1973, adult male from Tukuche village, Mustang District, Gandaki Province, Nepal, collected on 23 June 1973 by Ulrich Gruber and Dieter Fuchs.

Description of the holotype.

Adult male, indicated by the presence of hemipenes; 1 / 1 loreal, significantly higher than wide; nasal completely divided; 2 / 2 elongated preoculars, the lower narrower; 1 / 1 supraocular; 2 / 2 postoculars, upper reaching onto top of head and touching the parietal, the lower can be described as postsubocular, because it extends under the eye, up to the level of the posterior border of the third supralabial; rostral scale wider than high; two internasals wider than long; two prefrontals, longer than wide; frontal bell-shaped, barely longer than wide; 2 / 2 anterior temporals, upper significantly smaller than the lower one, and 2 / 2 posterior temporals, the lower one slightly larger than upper and in contact with the second last supralabial; supralabials 7 / 7, second last nearly three times higher than the previous one, in contact with lower posterior temporal, 3 rd / 3 rd in contact with the eye; pit opening shorter than the horizontal diameter of eye and encircled by 3 / 3 scales; 14 circum-pileus scales; 9 / 9 sublabials, first three in contact with anterior submaxillars; two pairs of submaxillars, anterior twice as wide and 67 % longer than posterior; followed by three rows of paired gular scales, increasing in size posteriorly; dorsal scales in 21-21 - 17 rows, strongly keeled, except the outer row, which is only very slightly keeled, paired apical pits on some dorsals, very weakly developed; three preventrals; 145 ventrals; cloacal plate entire; 42 / 42 paired subcaudal scales. Body compact, subcylindrical; tail short (TaL / TL 0.154); SVL 418 mm; TaL 76 mm, head length measured from tip of snout to posterior border of parietals 15.0 mm, head length measured from tip of snout to posterior edge of mandible 22.8 mm, head width 13.0 mm.

Dorsal scale reduction formula.

Dentition.

Maxillary bone with two posteriorly curved fangs on each side. On both sides the lateral fang is missing. Behind the main fangs are 7 / 8 replacement fangs at different growth stages. Main fang 3.98 mm in length, i. e., 22.8 % of skull length. Discharge orifice 0.70 mm in length, i. e., 17.6 % of fang length. Palatine bone with 3 / 3 posteriorly curved teeth slightly decreasing in size posteriorly. Teeth II loose on left, teeth I and III loose on right side. Lateral to each palatine tooth is a single replacement tooth at different growth stages. Pterygoid bone with 8 / 8 posteriorly curved teeth, shorter than the palatine tooth, all nearly the same size. Teeth I, III, V and VII loose on left side, as well as on right side. The posterior 64.5 % of the pterygoid bone is without teeth. Mandibular bone with 11 / 12 posteriorly curved teeth gradually decreasing in size posteriorly. The first two teeth closer together than the rest. Medial to each mandibular tooth are up to two replacement teeth in different growth stages. Teeth I, III, V and VII loose on left side. Teeth I, III, VII, IX and XI loose on right side. Splenial and angular bones are fused. The total length of splenial-angular complex spans 30.3 % of the mandibular bone. The dental is 37.6 % as long as the mandibular bone. The complete skull of the holotype ZMB 65613 is presented in Fig. 22.

Colouration and pattern.

Colouration after ~ 28 years preservation in ~ 70 % ethanol was recorded as follows: Dorsal ground colour Medium Fawn (Colour 257), with 32 Olive-Brown (278) roundish dorsolateral blotches with lighter Medium Fawn (257) centre, the outer edges of the blotches with darker Sepia (279) coloured margins, some blotches with a small dark Olive-Brown (278) spot in their centres; other blotches can be divided horizontally and form two semicircles or break up into four curved spots; lateral body blotches do not merge vertebrally; all dorsal scales show a dense Dark Grayish Brown (284) mottling; below the lateral blotches, a row of small, irregular rhombic or x-shaped Sepia (279) coloured and Cream White (52) bordered spots runs along the outer edge of the ventrals; tail with nine irregularly shaped Olive-Brown (278) spots; dorsal and upper lateral head sides with same ground colour as dorsal body and densely mottled with Dark Grayish Brown (284); pileus with small irregular shaped Olive-Brown (278) spots; neck with three Olive-Brown (278) stripes, the middle one shortest; a wide Sepia (279) postocular stripe runs from the posterior border of the eye to the posterior edge of the mandible, whose lower edge is bordered by a Dark Grayish Brown (284) wavy, narrow line; anterior and lower parts of posterior supralabials Pale Buff (1) and mottled with Dark Grayish Brown (284); venter with a colour gradient that becomes darker towards the tail; throat Pale Buff (1) coloured, submaxillars and gulars with numerous small Dark Grayish Brown (284) spots; sublabials Pale Buff (1) with small irregular Dark Grayish Brown (284) spots on their sutures; posteriorly, the venter gradually changes, from Pale Neutral Gray (296) with heavy Dark Grayish Brown (284) mottling via Light Neutral Gray (297) to Medium Neutral Gray (298); additionally to the dark mottling all ventrals with three to five squarish Dark Neutral Gray (299) or Dark Grayish Brown (284) spots which merge in the posterior third of the body; tail tip Light Buff (2) coloured. Examples of variation in the colouration and pattern of live individuals; see Fig. 23.

Variation.

The paratypes and other examined material agree well with the holotype in general appearance. For differences based on sexual dimorphism, morphometrics and scalation we refer to Tables 3, 4, 8. Meristic and morphometric characters of G. nepalensis sp. nov. can be summarised as follows: a single loreal, higher than wide or sometimes as high as wide; nasal completely divided or only exceptionally partly divided below naris; always two elongated preoculars, the lower narrower; a single supraocular; usually two, rarely three postoculars, upper reaching onto top of head and touching the parietal, the lower one can be described as postsubocular and touches with its anterior side the upper posterior edge of the third supralabial; rostral scale wider than high; two internasals wider than long; two prefrontals, ratio of length to width variable sometimes almost the same length; frontal bell-shaped, little longer than wide or as long as wide; predominantly three, often two, exceptionally four anterior and predominantly three, rarely four or two, exceptionally five posterior temporals; usually seven, rarely six, exceptionally eight supralabials, always the third in contact with the eye; 13–20 circum-pileus scales; usually nine, sometimes eight, rarely seven or ten sublabials, predominantly first three, rarely first four in contact with anterior submaxillars; two pairs of submaxillars, anterior usually twice as wide and 31–100 % longer than posterior; followed by 2–4 rows of paired gular scales, increasing in size posteriorly; anterior dorsal scales in 21 or 23, sometimes in 22 rows, midbody dorsal scales predominantly in 21, rarely in 19, exceptionally in 22 or 23 rows, posterior dorsal scales predominantly in 17, rarely in 15, exceptionally in 16 rows; predominantly two, sometimes one or three, rarely four or no preventrals; 140–161 ventrals (males 140–158, females 146–161); 38–48 paired subcaudal scales (males 39–48, females 38–42); sum of ventral and subcaudal scales 185–207 (males 185–207, females 188–205). Body compact, subcylindrical; tail short, ratio TaL / TL 0.124 –0.172 (males 0.124 –0.172, females 0.127 –0.156); maximum recorded SVL of examined material in males 609 mm, in females 535 mm; maximum recorded TaL of examined material in males 93 mm, in females 80 mm; maximum recorded TL of examined material in males 648 mm, in females 614 mm.

Sum formula of dorsal scale reduction in males.

Sum formula of dorsal scale reduction in females.

Variation in dentition.

Maxillary bone with two posteriorly curved fangs on each side. Main fang 3.38–5.85 mm in length, i. e., 22.8–30.6 % of skull length. Discharge orifice 0.55–1.35 mm in length, i. e., 14.84–23.1 % of fang length. Palatine bone with three or four posteriorly curved teeth slightly decreasing in size posteriorly. Pterygoid bone with 7–10 posteriorly curved teeth, shorter than the palatine tooth, all nearly the same size. The posterior 60.9–66.1 % of the pterygoid bone is without teeth. Mandibular bone with 10–12 posteriorly curved teeth gradually decreasing in size posteriorly. The first two teeth closer together than the rest. Splenial either 87.7–173.9 % of length of angular or fused. The total length of splenial-angular complex spans 24.2–36.6 % of the mandibular bone. The dental is 35.4–38.8 % as long as the mandibular bone.

Variation in live colouration and pattern.

Dorsal ground colour can vary from Tawny Olive (Colour 17) to Drab-Gray (256) or Smoke Gray (266); number of dorsolateral blotches varies from 26–33 on body and from 6–10 on tail; in some populations (e. g., Humla) body blotches can merge vertebrally and form irregularly shaped broad bands especially across the posterior part of body and tail; rarely a nearly completely striped morph is reported (Gumprecht et al. 2004: 66, fig. 1; Sharma et al. 2013: 51, fig. 83); dorsal ground colour can darken considerably to Sepia (279) during preservation, so that the dorsal pattern elements of the head and body are no longer recognisable.

Etymology.

The specific epithet nepalensis is a latinised adjective meaning " from Nepal, " referring to the country where the species was discovered. Located in the central Himalaya, Nepal encompasses an exceptionally diverse range of ecosystems, from subtropical lowlands to alpine environments. The name honours the geographic origin of the species and highlights the country’s ecological significance as part of the Himalayan biodiversity hotspot, which supports many range-restricted and endemic species. It also acknowledges Nepal’s increasing role in herpetological research and conservation in South Asia. The name has previously been used for various amphibian and reptile species, including Scutiger nepalensis Dubois, 1974, Minervarya nepalensis (Dubois, 1975), Cyrtodactylus nepalensis (Schleich & Kästle, 1998), or Ablepharus nepalensis (Eremchenko & Helfenberger, 1998).

Distribution.

Gloydius nepalensis sp. nov. is a central Himalayan species and so far reported only from western and west-central Nepal (Fig. 9). Records are known from the districts of Humla, Jumla, and Dolpa in the Karnali Province and from the districts of Mustang, Baglung, Myagdi, and Manang in the Gandaki Province (own data; Smith and Battersby 1953; Kramer 1977; Nanhoe and Ouboter 1987; Sura 1987; Gloyd and Conant 1990; Shah 1995; Schleich and Kästle 2002; see also Fig. 9 and Suppl. material 1: table SS 3). The distribution of the species is based on 26 geographic coordinates forming a polygon with a range of ca 20,400 km 2.

Various authors (e. g., Rai 2002; Schleich and Kästle 2002; Shah and Tiwari 2004; Kästle et al. 2013) list G. himalayanus (sensu lato) for eastern Nepal. According to our research, there is still no credible evidence, neither photographs nor preserved voucher specimens, from east of the Annapurna region. Earlier records were mostly based on misidentified Mountain Pitvipers (Ovophis monticola) as listed and depicted in Schleich and Kästle (2002: 1068 No 1, 2 and 15, pl. 111, figs 329–330; see also comments by Gumprecht et al. 2004: 20).

Habitat and ecology.

Gloydius nepalensis sp. nov. is recorded from elevations between 1640 and 3220 m (see Suppl. material 1: table SS 3). The species is associated with dry areas where it was found in open rocky habitats with scattered small bushes and stones on slopes near dry coniferous forests consisting of Picea and Pinus spp. It is recorded from subalpine shrublands and alpine meadows but also from the vicinity of small rivers with low trees and near cultivated areas (Dierl and Gruber 1979; Nanhoe and Ouboter 1987: 47; Gumprecht et al. 2004: 348 fig. I; Shah and Tiwari 2004). This species is not strictly nocturnal. It feeds on frogs, small lizards, and rodents (pers. obs.; Nanhoe and Ouboter 1987; Schleich and Kästle 2002; Shah and Tiwari 2004). Hibernation periods differ depending on local climate and altitude and can last up to seven months. Reproduction is ovoviviparous with mating in April or May and the birth of 5–7 neonates in September, with a total length varying from 163–199 mm and a weight of 3.5–5.1 g (pers. obs.).

Conservation.

The species is considered to be common in the distributional area (Shah 1995; Shrestha 2001; Schleich and Kästle 2002; Shah and Tiwari 2004) and Nepalese populations are listed under Gloydius himalayanus as " Least Concern " by the IUCN Red List of Threatened Species (Limbu and Ghosh 2022).