Red-eyed Whipsnake

description

Description of holotype. Adult male; head elongate and triangular (HL / HW = 2.68), distinct from neck; body elongate and compressed; SVL 682 mm; tail long (TaL / TL = 0.35), 370 mm in length; eye small, pupil horizontal, eye diameter much shorter than snout length (SnL / ED: 2.33); snout pointed without dermal appendage. Head scalation. Dorsal head scales smooth, abutting along midline rather than overlapping (Fig. 2); rostral directed forward and upward, well visible from above, touching nasals, internasals and 1 st supralabial on both sides; supralabials 8 / 8, 4 th, and 5 th bordering eye; 3 / 3 loreals; 1 / 1 presubocular; 1 / 1 enlarged preocular; 2 / 2 postoculars; nostril in posterior part of an elongated nasal; 2 + 2 / 2 + 2 temporals, with a very small scale on left side bordered by anterior temporals and postoculars; internasals longer than wide (3.0 mm in length and 1.9 mm in width), separated posteriorly from supralabials by two loreals on both sides; prefrontal bending down sharply at canthus, strongly convex, longer than wide (4.3 mm long and 2.7 mm wide), larger than internasal; frontal longest (7.6 mm long and 4.4 mm wide), widened anteriorly and much narrowed post

A new species of Ahaetulla Link, 1807 (Squamata: Colubridae) from the Mekong Delta, Vietnam

diagnosis

Diagnosis. Ahaetulla rufusoculara sp. nov. is distinguished from all of its congeners by a combination of the following morphological characters: bright red eyes; medium size in adult (largest TL 1085 mm in male); snout without dermal appendage, more than two times as long as the eye diameter in adult (SnL / ED 2.33 – 2.37); internasal separated from supralabial by loreal; body scale rows 15 - 15 - 13; tail long (TaL / TL ratio 0.34 – 0.35 in males and 0.31 – 0.32 in females); ventrals 186 – 190 in males and 182 – 185 in females; subcaudals 143 – 153 in males and 128 or 129 in females; 8 (rarely 9) supralabials, fourth and fifth or fourth to sixth entering orbit; 12 – 14 maxillary teeth; hemipenis short, reaching 6 th or 7 th SC; cloacal plate divided; dorsum bright green; and yellow or white stripe along lower flank.

A new species of Ahaetulla Link, 1807 (Squamata: Colubridae) from the Mekong Delta, Vietnam

distribution

Distribution. The new species is currently known only from My Phuoc Forest, My Tu District, Soc Trang Province, Vietnam (Fig. 6).

A new species of Ahaetulla Link, 1807 (Squamata: Colubridae) from the Mekong Delta, Vietnam

etymology

Etymology. The specific epithet rufusoculara refers to the red color of the eyes and is derived from the Latin adjective rufus (meaning “ red ”) and oculus (means “ eye ”). We recommend “ Red-eyed vine snake ” and “ R ắn roi m ắt đȯ ” as the common English and Vietnamese names of the new species, respectively. Comparisons. Ahaetulla rufusoculara sp. nov. differs morphologically from all congeners as follows: from A. anomala Annandale, A. borealis Mallik, Srikanthan, Pal, D’Souza, Shanker & Ganesh, A. farnsworthi Mallik, Srikanthan, Pal, D’Souza, Shanker & Ganesh, A. isabellina (Wall), A. laudankia Deepak, Narayanan, Sarkar, Dutta & Mohapatra, A. malabarica Mallik, Srikanthan, Pal, D’Souza, Shanker & Ganesh, A. nasuta, A. oxyrhyncha (Bell), A. pulverulenta (Dumeril, Bibron & Dumeril), and A. sahyadrensis Mallik, Srikanthan, Pal, D’Souza, Shanker & Ganesh by the absence (vs. presence) of dermal appendage on snout (Deepak et al. 2019; Mallik et al. 2020); from A. dispar (Gunther) by having more ventrals (182 – 190 vs. 136 – 156) and more subcaudals (128 – 153 vs. 84 – 119) (Smith 1943); from A. fasciolata (Fischer) by having fewer ventrals (182 – 190 vs. 221 – 231), fewer subcaudals (

A new species of Ahaetulla Link, 1807 (Squamata: Colubridae) from the Mekong Delta, Vietnam