Hebius leucomystax ( David, Bain, Nguyen, Orlov, Vogel, Vu, and Ziegler, 2007 )

Nguyen, Tan Van, Brakels, Peter, Maury, Nathanael, Sudavanh, Somchit, Pawangkhanant, Parinya, Idiiatullina, Sabira, Lorphengsy, Sengvilay, Inkhavilay, Khamla, Suwannapoom, Chatmongkon & Poyarkov, Nikolay A., 2020, New herpetofaunal observations from Laos based on photo records, Amphibian & Reptile Conservation (e 248) 14 (2), pp. 218-249 : 235

Hebius leucomystax ( David, Bain, Nguyen, Orlov, Vogel, Vu, and Ziegler, 2007)

White-lipped Keelback ( Fig. 8B )

One individual of H. leucomystax was observed by P. Brakels on 28 September 2019 in Paksong (1) District, Champasak Province (15°24.529’N, 106°38.148’E; elevation 880 m asl), and one other individual was found by S. Lorphengsy on 25 October 2017 in Thaphabath District , Bolikhamxai Province (18°27.557’N, 103°83.543’E; elevation 330 m asl) .

Morphological characters of the individuals from Champasak and Bolikhamxai provinces agreed well with the descriptions of David et al. (2007) and Stuart and Heatwole (2008). The photographed individual ( Fig. 8B ) agrees with the diagnosis of H. leucomystax in the following characters: body rather elongate, slender; head distinct from neck; eye moderately large; pupil round; loreal present, not entering the orbit; 1 preocular; 3 postoculars; 1 anterior temporals; 2 posterior temporals; 9 supralabials, 1 st and 2 nd in contact with the nasal, 2 nd and 3 rd in contact with the loreal, 4 th and 6 th entering orbit, 6 th and 7 th largest; dorsal scale rows strong all keeled; ventrals 158; cloacal divided; subcaudals 110, divided. Coloration of dorsal head scales dark gray with a weak light longitudinal line extends on hind part of head; dorsal surface dark gray with dark spots and irregular bars, dorsolateral spots extend to tail; venter surface cream.

Ecological notes. The individual from Paksong , Champasak Province, was found on the bank of a small stream, the surrounding habitat consist of extensive bamboo stalks. The individual from Bolikhamxai Province was found near the large stream, of which the surrounding habitats are secondary forest with bamboo and shrubs .

Distribution. In Laos, this species has been recorded previously from Khammouan and Xekong provinces (Stuart and Heatwole 2008). This is the third record from the country as well as the first ones from Champasak and Bolikhamxai provinces. Elsewhere, this species has been reported from Vietnam, Cambodia, and Thailand ( Uetz et al. 2020).

Figures

Fig. 8. (A) Hebius chapaensis in Longcheng District, Xaisomboun Province; (B) H. leucomystax in Paksong District, Champasak Province; (C) Lycodon fasciatus in Longcheng District, Xaisomboun Province; (D) L. futsingensis in Xay district, Oudomxai Province; (E) Ptyas multicincta (var. bicolor) in Gnommalath District, Khammouan Province; (F) P. multicincta (var. multicincta) in Vang Vieng District, Vientiane Province. Photos by P. Brakels (A, C, D), N. Maury (B, F), and P. Pawangkhanant (E).