A new species of Oligodon Fitzinger, 1826 from the Langbian Plateau, southern Vietnam, with additional information on Oligodon annamensis Leviton, 1953 (Squamata: Colubridae)

Abstract

We describe a new species of Oligodon from the highlands of the Langbian Plateau, southern Truong Son Mountains, Vietnam, based on morphological and molecular phylogenetic analyses. The new species, Oligodon rostralis sp. nov is distinguished from its congeners by the following morphological characters: medium size in adults (male TL = 582 mm); small and broad head with long protruding snout; dorsal scale row formula 15-15-13; 167 ventrals, 47 subcaudals; single preocular, single postocular; loreal and presubocular absent; six supralabials, third and fourth entering orbit; six infralabials, anterior four contacting first pair of chin shields; internasals separate from prefrontals; nasal divided; single anterior and two posterior temporals; cloacal plate undivided; hemipenes short, bilobed, bifurcating in anterior one third of their length, extending to 8th subcaudal, lacking spines and papillae, with a prominent transverse flounces and distal calyces; six maxillary teeth, the posterior three enlarged; dorsal pattern consisting of 14+4 large dark-brown blotches and a bright-orange vertebral stripe on tail and dorsum; and ventral surfaces in life cream laterally with dark quadrangular spots; dark temporal streak present, edged with white. We also provide additional information on O. annamensis, including a morphological dataset of all specimens known from natural history collections and confirmation of an earlier record of O. annamensis from Cambodia. We also provide the first record of O. annamensis for Dak Lak Province. Phylogenetic analyses of mtDNA genes (3,131 bp of 12S rRNA, 16S rRNA and cyt b) suggest sister relationships of Oligodon rostralis sp. nov. and O. annamensis and place them in one clade with the O. cyclurus and O. taeniatus species groups, which is concordant with previous studies on the phylogenetic relationships of Oligodon. Our study demonstrates high level of herpetofaunal diversity and endemism of Langbian Plateau and further supports the importance of this area for conservation herpetofaunal diversity in Indochina.

An integrative taxonomic revision of slug-eating snakes (Squamata: Pareidae: Pareineae) reveals unprecedented diversity in Indochina

“…Our work further highlights the importance of the Indochinese region, including the territories of Vietnam, Laos, Cambodia, and Thailand, as one of the key biodiversity hotspots with high levels of herpetofaunal diversity and endemism ( Bain & Hurley, 2011 ; Geissler et al, 2015 ; Duong et al, 2018 ; Nguyen et al, 2018 , 2019 , 2020b , 2020c ; Poyarkov et al, 2018b , 2019 , 2021 ; Grismer et al, 2019 , 2021a , 2021b ; Chomdej et al, 2021 ; Uetz, Freed & Hošek, 2021 ). This area is facing many pressures with major habitat loss by deforestation due to logging, the growing human population density and infrastructure development, agricultural extension, forest fires, and tourism development ( Lang, 2001 ; Meyfroidt & Lambin, 2009 ).…”

A new species of snake of the genus Oligodon Boie in Fitzinger, 1826 (Reptilia, Serpentes) from the Western Himalayas

“…The colubrid snake genus Oligodon Boie in Fitzinger, 1826 is represented by 84 species distributed throughout Asia (Uetz and Hallermann 2021) and the number of species within the genus has increased considerably in the recent past. This is a result of description of several new species largely due to an integrated taxonomic approach (Nguyen et al 2020). The high diversity with morphologically cryptic species and secretive behavior of members of the genus makes species delimitation a daunting task (Smith 1943;Whitaker and Captain 2004;Tillack and Günther 2009;Nguyen et al 2020).…”

“…This is a result of description of several new species largely due to an integrated taxonomic approach (Nguyen et al 2020). The high diversity with morphologically cryptic species and secretive behavior of members of the genus makes species delimitation a daunting task (Smith 1943;Whitaker and Captain 2004;Tillack and Günther 2009;Nguyen et al 2020). Furthermore, lack of molecular data for all known species, especially from type localities of the relevant taxa makes compilation of revi-sionary work difficult, more so for cryptic species.…”

Eviscerated alive: Novel and macabre feeding strategy in Oligodon fasciolatus (Günther, 1864) eating organs of Duttaphrynus melanostictus (Schneider, 1799) in Thailand

“…The genus Oligodon currently contains 80 species that collectively range from Iran, Turkmenistan, Afghanistan in the west, over large parts of India and Sri Lanka to China and the Philippines in the east and south through South Asia to Indonesia (De Lang 2017;Midtgaard 2019;Nguyen et al 2020;Uetz et al 2020). These snakes are small to medium-sized with a muscular body and short head which is not distinct from the body.…”