Herpetoreas xenura ( Wall, 1907 )

Nguyen, Tan Van, Ray, Sumidh, David, Patrick & Mohapatra, Pratyush P., 2025, Designation of a Neotype for Herpetoreas xenura (Wall, 1907) (Squamata: Serpentes: Natricidae), Zootaxa 5620 (1), pp. 196-200 : 197-198

Herpetoreas xenura ( Wall, 1907)

Tropidonotus xenura Wall 1907: 616 —

Holotype: lost. Neotype (designated herein) ZSI R-4278 , adult female, collected by J. H. Bourne in 1871 and entered in the register on 18 March 1880. — Type locality. By virtue of the designation of a neotype: Cherrapunji (or Sohra) , East Khasi Hill District, Meghalaya State, India. Original type locality: not specified .— Wall (1909: 145, in part).

Natrix xenurus — Wall (1923: 601); Smith (1943: 292, in part); Romer (1945: 430–431).

Paranatrix xenura — Mahendra (1984: 244).

Amphiesma xenura — Das (1996: 54); Pawar & Birand (2001: 56, 102); Ziegler & Le (2006: 44); David et al. (2007: 41–60); Wallach et al. (2014: 35).

Hebius xenura — Guo et al. (2014: 425–440).

Herpetoreas xenura — Lalronunga et al. (2020: 193–200); Hmar et al. (2020: 821–826); Muansanga et al. (2021: 82–83); Malsawmdawngliana et al. (2021: 667); Lalremsanga et al. (2022: 101–115); Malsawmdawngliana et al. (2022: 21946 – 21960); Ren et al. (2022: 79); Nguyen et al. (2024: 158–203).

Tropidonotus modestus (non Hebius modestus (Günther, 1875)) — Sclater (1891: 36, in part).

Amphiesma venningi (non Hebius venningi (Wall, 1910) — Mathew & Meetei (2004: 134–135, in part); Reza (2010: 64–72).

Description of the neotype of Tropidonotus xenura ( Fig.1 ). An adult female, in relatively good state of preservation after more than 140 years in preservative.

Morphology. Body slender, cylindrical, and elongate. Snout-vent length 452.2 mm, tail length 159.9 mm, total length 612.1 mm, ratio tail length/total length 0.261. Head moderately large (head length 19.8 mm, head width 12.0 mm), moderately distinct from neck; snout broad, obtuse as seen from above; eye large (eye diameter 3.2 mm, eye-snout distance 5.1 mm, eye-nostril distance 3.0 mm); pupils round; nostrils crescentic, piercing in the middle of the nasal, oriented laterally.

Body scalation. Dorsal scales in 19-19-17 rows; all scales strongly keeled, notched at apex; Dorsal scale rows reduction: scales around the body reduced from 21 to 19 at the levels of the 7 th ventral on the right side and 5 th ventral on the left side by fusion of 3 rd and 4 th rows of dorsal scales; second reduction from 19 to 17 by fusion of 3 rd and 4 th rows of dorsal scales at the levels of the 112 th ventral on the right side and 110 th ventral at left side); 155 ventrals (plus three preventrals); cloacal plate divided, right side overlapping the left side; 81 subcaudals, all single.

Head scalation. Rostral wider than high, wide, approximately twice as wide as high, not visible from above; nasals pentagonal, slightly elongate, completely divided by a suture, anterior part slightly smaller than the posterior one; nostrils located in the middle of nasals; internasals subtriangular, in broad contact with each other, not in contact with loreal, about as long as wide, slightly, but distinctly narrowing anteriorly, the width of the posterior margin approximately twice as long as the anterior margin; 2 prefrontals, hexagonal, slightly broader than long, about 1.3 times as long as internasals; prefrontal sutures slightly longer than length of internasal sutures; frontal pentagonal, elongate, 1.4 times as long as wide, about twice as long as prefrontal; supraocular 1/1, rectangular, elongate, narrowing anteriorly, broadly in contact with prefrontal, with supraocular two-thirds as broad as the frontal; parietals in broad contact with each other, parietal suture subequal to length of frontal. Loreal 1/1, subrectangular, small, about equal in length to depth, in contact with 2 nd –3 rd supralabials on left side and 2 nd –4 th supralabials on right side, not entering orbit; preoculars 1/1; postoculars 3/3, their size decreasing from top to bottom; supralabials 9/10, 4 th –6 th entering orbit on left side and 5 th –7 th entering orbit on right side, 8 th largest in left side and 9 th in right side; temporals 2+3 on both sides; mental subtriangular, wide, 2.5 times as long as high; 11/11 infralabials, first pair in contact with each other behind mental, 1 st –6 th in contact with anterior chin shields; two pairs of chin shields; posterior chin shields 1.3 times as long as anterior ones, separated from each other by small scales; mental groove apparent.

Variation. The neotype designated here (ZSI R-4278) along with ZSI R-14942 (now NHMUK 1940.3.4.8) and ZSI R-14943 examined by us have divided cloacal plate. However, the specimens of Herpetoreas xenura referred by Nguyen et al. (2024) housed in the Departmental Museum of Zoology, Mizoram University, Mizoram, India (MZMU), bearing registration numbers MZMU 810–820, and MZMU 3271 except MZMU 1211 have their cloacal plate single (Gernot Vogel: pers. comm.) and may correspond to another undescribed species under the genus Herpetoreas .

Figures

FIGURE 1. Herpetoreas xenura specimen ZSI R-4278 (neotype, adult female) in preservative. A—General dorsal view; B— General ventral view; C—Lateral view of the head, right side; D—Lateral view of the head, left side; E—Dorsal view of the head; F—Ventral view of the head; G—Ventral side of the tail. Photos by P.P. Mohapatra.