Vo Quy’s Mountain Stream Keelback

description

Description of holotype. Body stout, oval in cross section; head short, slightly broader than neck, depressed, dorsally covered with large shields; nostrils in dorsal position and oblique, narrow, piercing the middle of nasal, which is divided beneath; eye small, pupil round. Size. SVL: 337 mm; TaL: 106 mm; TL: 443 mm; ratio TaL / TL: 0.239. Dentition. Maxillary teeth: right upper maxilla with 25 subequal teeth or sockets, without diastema. Body scalation. Dorsal scale rows 15 – 15 – 15, smooth, with few faint keels. 181 ventrals (+ 1 preventral); 85 subcaudals, all paired; precloacal divided. Head scalation. Rostral heptagonal, wider than high, readily visible from above; nasals large, much longer than high, divided below nostril by a distinct furrow; internasals two, strongly curved, longer than wide, in contact with rostral, nasals, and prefrontal; prefrontal single, anteriorly pointed, much broader than long, in contact with internasals, nasals, loreals, preoculars, and frontal; frontal pentagonal, slightly wider than long, apex directed posteriorly, 1.3 times longer than prefrontal; parietals longer than wide, in contact approximately the length of frontal; 1 / 1 supraocular,

Morphological and molecular review of Jacob’s Mountain Stream Keelback Opisthotropis jacobi Angel & Bourret, 1933 (Squamata: Natricidae) with description of a sibling species from northern Vietnam

description

O. kuatunensis Pope, 1928 x O. lateralis Boulenger, 1903 x O. latouchii (Boulenger, 1899) x

Morphological and molecular review of Jacob’s Mountain Stream Keelback Opisthotropis jacobi Angel & Bourret, 1933 (Squamata: Natricidae) with description of a sibling species from northern Vietnam

description

Opisthotropis voquyi sp. nov. differs from O. kikuzatoi by 7 – 9 supralabials (versus 6), one preocular (versus two), one anterior temporal (versus two), and the greyish to greyish-brown or brown dorsal pattern, with the dorsals posteriorly being more or less edged with pale greyish-brown in the new species (versus dark dorsum with dorsolateral orange spots). Opisthotropis voquyi sp. nov. differs from O. maculosa by a grey to greyish-brown or brown dorsum, with dorsals being posteriorly more or less edged with pale greyish-brown in the new species versus with yellow dots on a dark background in O. maculosa. In external morphological characters, O. voquyi sp. nov. is particularly similar to O. jacobi, from which it differs in usually having two postoculars versus only one in O. jacobi, in the number of maxillary teeth: 25 in the new species versus 19 – 23 in O. jacobi, and in the dorsal scales being grey to greyish – brown or brown versus blackish – brown in O. jacobi.

Morphological and molecular review of Jacob’s Mountain Stream Keelback Opisthotropis jacobi Angel & Bourret, 1933 (Squamata: Natricidae) with description of a sibling species from northern Vietnam

distribution

Distribution. Opisthotropis voquyi is currently known only from the type locality in Bac Giang Province (Fig. 11). Natural history. Specimens were found at night between 19: 30 and 23: 00 h in and around small rocky streams, where the snakes were observed in the water or on the rocks close to the water. The surrounding habitat was secondary evergreen forest of medium and small hardwoods mixed with bamboo, shrubs, and vines (Fig. 12). The air temperature was 29.2 – 36.5 o C and the relative humidity was 55 – 73 %. Other species co-occurring with Opisthotropis voquyi include Cyclophiops multicinctus, Opisthotropis lateralis, Sinonatrix percarinata, Gekko palmatus, Sphenomorphus cryptotis, and Shinisaurus crocodilurus vietnamensis.

Morphological and molecular review of Jacob’s Mountain Stream Keelback Opisthotropis jacobi Angel & Bourret, 1933 (Squamata: Natricidae) with description of a sibling species from northern Vietnam