A new species of the genus Oligodon Fitzinger, 1826 (Squamata: Colubridae) from coastal southern Vietnam

Abstract

A new species of the genus Oligodon from the coastal area of Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province, southern Vietnam, is described. Oligodon arenarius sp. nov. is distinguishable from all other species by the unique combination of the following characters: medium size; 17 dorsal scale rows; 6-8 maxillary teeth, the posterior three being enlarged; head scalation lacking a loreal but usually including a presubocular; divided nasal; two postoculars; 131-144 ventrals; 36-60 subcaudals; unforked hemipenis, without spines or obvious papillae; sexual dimorphism displayed in the number of subcaudals (36-40 in females, 58-60 in males) and a relative tail length, tails being quite long in males (TaL/TL = 0.26-0.28) and moderate in females (TaL/TL = 0.13-0.17); head coloration pattern including ocular band, temporal bands and chevron-shaped mark on nape; dorsal coloration without distinct pattern, uniform or with dark speckling; ventrals pinkish in life, immaculate. To date, this species appear to be endemic to Vietnam.

Oligodon saiyok, a new limestone-dwelling kukri snake (Serpentes: Colubridae) from Kanchanaburi Province, western Thailand

“…Measurements and meristic counts follow David et al (2008a). All measurements were taken with a slide-caliper to the nearest 0.1 mm.…”

“…Comparisons were made using original species descriptions and revisions (see References; David et al 2008ab;Orlov et al 2010;van Rooijen et al 2011;Zhang et al 2011;Hasan et al 2013;Vassilieva et al 2013;Vassilieva 2015;Nguyen et al 2016 and literature cited therein) and preserved museum material in the Chulalongkorn University Museum of Zoology, Reptile Collection, Bangkok (CUMZ (R)), Institut Royal des Sciences Naturelles de Belgique, Brussels (IRSNB), Muséum national d'Histoire naturelle, Paris (MNHN), Queen Saovabha Memorial Institute, Thai Red Cross Society, Bangkok (QSMI), Royal Forest Department of Thailand, Bangkok (RFD), Natural History Museum, National Science Museum, Technopolis, Pathum Thani (THNHM) and United States National Museum, Washington (USNM) (see Appendix).…”

“…The Kukri snakes of the genus Oligodon Boie in Fitzinger, 1826 are distributed throughout tropical Asia and the genus currently includes about 76 recognized species, which makes of it one of the largest Asian snake genera (Uetz et al 2016). Recent revisions showed that several species are in reality species complexes, and a dozen species have already been described in the 21 st Century, with more descriptions to come (David et al 2008a(David et al -b, 2011(David et al , 2012. All species show a characteristic habitus, without marked neck, with a large rostral in relation to their semi-fossorial habits, and with typical kukri-shaped posterior maxillary teeth.…”

“…Within the distribution of the genus, the Indochinese Peninsula and Thailand show the highest species diversity. More and more taxa with limited geographic distributions are discovered, some of them restricted to specific ecosystems such as sand dunes or limestone hills (Neang et al 2012;Vassilieva 2015;Nguyen et al 2016).…”

“…Green 2010;Green et al 2010;Orlov et al 2010;Neang et al 2012;Neang & Hun 2013;Vassilieva 2015). Because the hemipenes of the holotype of Oligodon saiyok sp.…”