Hebius khasiensis

Hebius khasiensis (Boulenger, 1890) (Fig. 4, 5, 6, 9, 10A and 10B; Table 3) Tropidonotus khasiensis Boulenger 1890: 344 — Type Locality. Khasi Hills (25°34N, 91°53E; 1,525 m asl approx), Meghalaya, northeast India — Lectotype (by present designation) (Formerly syntypes): BMNH 1946.1.12.80, an adult female collected by T. C. Jerdon from Khasi Hills (25°34N, 91°53E; 1525 m asl approx), Meghalaya, northeast India; Paralectotypes: BMNH 1946.1.12.81 and BMNH 1946.1.12.82, two adult males bear the same collection details as the lectotype and BMNH 1946.1.13.45, a juvenile female collected by Sir J. Hooker from the same locality as the lectotype. Chresonyms Tropidonotus khasiensis — Boulenger 1893a: 322, 1893b: 223: Plate 13: Fig. 3; Annandale 1905:210, 1912: 49 & 53; Wall 1908: 316, 317: Fig. 2. Natrix khasiensis — Wall 1923: 601; Wall 1926:559 (Wall himself synonymized his described species gilhodesi with khasiensis); Bourret 1936 a, b; Smith 1943: 289. Amphiesma khasiensis — Malnate 1960; Das 1996: 53; Sharma 2004. Paranatrix modesta (non Tropidonotus modestus Günther, 1875)— Mahendra 1984:247 (The consideration of H. khasiensis as a synonym of H. modestus was erroneous; see David et al. 2013:8). Amphiesma khasiense — Whitaker & Captain 2004: 25, 218 & 219; Ziegler et al. 2006; Ahmed et al. 2009: 19; Wallach et al. 2014: 30; Chan-ard et al. 2015: 233. Amphiesma cf. khasiense — Grismer et al. 2007. Hebius khasiense — Guo et al. 2014 (implicitly). Hebius khasiensis — Zhou et al. 2019; David et al. 2021. Materials examined: Syntypes — BMNH 1946.1.12.80, an adult female collected by T.C. Jerdon from Khasi Hills (25°34N, 91°53E; 1525 m asl approx), Meghalaya, northeast India; BMNH 1946.1.12.81 and BMNH 1946.1.12.82, two adult males bear the same collection details as the above female syntype; BMNH 1946.1.13.45, a juvenile female by Sir J. Hooker from Khasi Hills (25°34N, 91°53E; 1525 m asl approx), Meghalaya, northeast India. Lectotype (Fig. 4.) (By present designation)— BMNH 1946.1.12.80, an adult female collected by T.C. Jerdon from Khasi Hills (25°34N, 91°53E; 1525 m asl approx), Meghalaya, northeast India. Paralectotypes (Fig. 5)— BMNH 1946.1.12.81 and BMNH 1946.1.12.82, two adult males bear the same collection details as the lectotype; BMNH 1946.1.13.45, a juvenile female collected by Sir J. Hooker from the same locality as the lectotype. Additional topotypic and referred materials: MZMU 3526 (Fig. 6), an adult female collected by Sanath Chandra Bohra and Holiness Warjri on 12 th April 2024 at around 21:45 h from Mairang, Eastern West Khasi Hills district (25.559415°N, 91.635047° E; 1564 m asl), Meghalaya, India; MZMU2810, MZMU2973, MZMU3239, all adult females collected by H. T. Lalremsanga, Lal Biakzuala and others from Tamdil National Wetland (23.728665°N, 92.956578°E), Aizawl district, Mizoram, India; MZMU2706, a juvenile female collected by H. T. Lalremsanga, Lal Biakzuala and others from Theiriat (22.868358°N, 92.788137°E), Lunglei district, Mizoram, India; MZMU2540, an adult female collected by H. T. Lalremsanga, Lal Biakzuala and others from Sailam (23.350624°N, 92.797968°E), Aizawl district, Mizoram, India; MZMU2096, an adult female collected by H. T. Lalremsanga, Lal Biakzuala and others from Durtlang (23.795506°N, 92.726469°E), Aizawl district, Mizoram, India; MZMU1304, an adult female collected by H. T. Lalremsanga, Lal Biakzuala and others from Reiek (23.677444°N, 92.603713°E), Aizawl district, Mizoram, India; MZMU1531, an adult female collected by H. T. Lalremsanga, Lal Biakzuala and others from Sawleng (23.981553°N, 92.930910°E), Aizawl district, Mizoram, India; MZMU923, an adult male by H. T. Lalremsanga, Lal Biakzuala and others from Durtlang (23.795506°N, 92.726469°E), Aizawl district, Mizoram, India. Notes: Since Tropidonotus (Hebius) khasiensis was described based on four syntypes, the species would be taxonomically stable after designating a lectotype. Herein, we have designated BMNH 1946.1.12.80, an adult female as the lectotype for the given species as it appears to be more morphologically pronounced and is the only specimen with a complete (though broken) tail amongst our syntypes. In the literature alongside the description, Boulenger (1893) stated that he had a total of three adult females and an unsexed juvenile specimen (four syntypes formerly) in the original type series but upon examination it was observed that the type series comprises of one adult female (designated as the lectotype herein), two adult males and a juvenile female (see David et al. 2013). Diagnosis and Description: A medium sized natricid snake growing upto a maximum SVL of 412 mm and is diagnosed from all other congeners based on the combination of the following characters: (1) cylindrical body with 19 (OSR):19 (MSR):17 (PSR) dorsal scale rows, all of which are strongly keeled except for the OSR and the outermost row close to ventral edges that are usually very feebly keeled, rarely moderately keeled. Posterior region close to the base of the tail are always strongly keeled (2) ventrals 145–157 (plus 1 or 2 preventrals) (3) subcaudals 91–103, all paired or divided (4) anal plate divided or paired (5) tail relatively long with a Tal/TL ratio of 0.275 –0.341 (6) 8–9 supralabials or upper labials out of which 3 rd, 4 th and 5 th or 4 th, 5 th and 6 th (rarely 4 th and 5 th) are touching the orbit and the last three supralabials are comparatively much larger (7) 10–11 infralabials or lower labials out of which the first five are touching the first pair of anterior chin shields; First pair of infralabials are the longest and are in contact with each other behind mentals (8) nasal scale distinct and divided, nostril lies laterally in the center of the nasal scale (9) internasals divided or paired (10) a single loreal scale dorso-laterally present on either side of the head (11) 17–21 maxillary teeth on both sides, slightly getting enlarged posteriorly including the last two to three posterior teeth without proper diastema that are moderately enlarged as compared to the anterior ones (12) dorsal body coloration in life mostly ranges from chocolate brown to sepia or blackish brown along with two thin and parallel rusty brown or burnt sienna dorso-lateral stripes that are properly visible from above, each stripe running just from behind the nape till the base of the tail dorsally on either side. The thin rusty brown dorso-lateral stripes are at times slightly faded and frequently interrupted as well as intermixed with a continuous series of distinct ochre yellowish spots of nearly equal width (13) upper lips or supralabials are usually off white in coloration intermixed with distinct black markings that are usually present in and around the marginal edges of each supralabial scale, the black markings become comparatively much larger in the last three supralabials (14) nape with a short but continuous, distinct off whitish or creamish streak which begins just behind the last supralabial scale, thereby covering a length of 5–8 continuous scales and nearly touches the anterior portion of rusty-brown dorso-lateral stripe in the neck (15) upper portion of the head mainly has two shades of coloration ranging from chocolate brown to sap greenish intermixed with irregular creamy yellowish spots (16) ventral region is completely off-white in coloration along with the presence of distinct black spots on the ventral edges of each ventral, anal and each subcaudal scale throughout, thereby forming a somewhat thin, distinct and dark ventro-lateral line like appearance. Description of the lectotype (Fig. 4)—An adult female with a cylindrical as well as a slender body having a TL (total length) of 604 mm, SVL 412 mm, Tal 192 mm and a Tal/TL ratio of 0.318. Head is elongated and moderately large, somewhat distinct from neck (HL/SVL 0.04); Snout is rather large, sub-equally as long as broad and semi-oval in shape as seen from above. Eye is moderately large (ED1 3.0 mm; ED2 2.9 mm) and pupils are round. Rostral is partially visible from above, much wider than high and is in broad contact with 1 st supralabial, anterior portion of nasal as well as inter-nasals; nasal scale on either dorso-lateral side of the head, irregularly pentagonal and somewhat elongated; the nasals are completely divided sub-equally into anterior and posterior portions by a somewhat perpendicular suture above and below the crescentic nostril; the nostril lies right in the center of the nasal scale laterally; a pair of internasals clearly visible from above, slightly longer than broad (L–INas 2.0 mm; W–INas 1.8; W–INas/L–INas 0.9) and are in broad contact with each other; each internasal is irregularly sub-triangular in shape and is in contact with rostral, nasal and prefrontal scales, but the portion of internasals broadly contacting nasals on the lateral sides of the head are somewhat semicircular in shape; a pair of pre-frontals that are irregularly hexagonal in shape and are somewhat sub-equal in length and width and are broadly connected with each other; prefrontal larger than internasal in terms of both length as well as width (L–INas/LPreFro 0.8; W–INas/W–PreFro 0.8) and prefrontal sutures slightly longer than internasal sutures; prefrontal is in contact with internasal, nasal, loreal, preocular, supraocular and frontal; frontal pentagonal, elongated, longer than broad (FL 4.4 mm, FW 3.2 mm; FW/FL 0.7), about twice longer than prefrontal length (L–PreFro/ FL 0.5) and is in contact with prefrontal, supraocular as well as parietal; one elongated supraocular above the eyeball on either side that is anteriorly narrowed, irregularly rectangular and is in contact with prefrontal, preocular, frontal, parietal as well as postocular; a pair of parietals that are large, much longer than broad (L–Par 6.4mm, W–Par 3.1mm;W–Par/L–Par 0.5), broadly in contact with each other and are also in contact with the dorsal scales on the occiput, temporals (anterior as well as posterior), pos