Keywords :
cryptic species,
molecular phylogenetics,
monocled cobra,
phylogeography,
snakes
บทคัดย่อ :
South-East Asia has an exceptionally high diversity of snakes, with more than 250 snake
species currently recorded from Thailand. This diversity likely reflects the diverse range
of geographical and climatic conditions under which they live, but the evolutionary his-
tory and population genetics of many snake species in South-East Asia have been little
investigated in comparison with morphological studies. Here, we investigated genetic var-
iation in the monocled cobra, Naja kaouthia, Lesson, 1831, across its distribution range in
Thailand using mitochondrial DNA (cytochrome b, control region) for ~100 individuals
and the nuclear DNA gene (C-mos) for a small subset. Using population genetic and phy-
logenetic methods, we show high levels of genetic variation between regional populations
of this non-spitting cobra, including the north-eastern, north-central and southern regions,
in addition to a population on Pha-ngan Island, 150 km offshore from the southern penin-
sula. Moreover, inclusion of the north-eastern population renders N. kaouthia paraphyletic
in relation to other regional Naja species. The north-eastern population is therefore prob-
ably specifically distinct. Given that these cobras are otherwise undifferentiated based
on colour and general appearance to the typical cobra type of this region, they would
represent a cryptic species. As has been shown in other animal groups from Thailand, it is
likely that the geographical characteristics and/or tectonic alteration of these regions have
facilitated high levels of population divergence of N. kaouthia in this region. Our study
highlights the need for dense sampling of snake populations to reveal their systematics,
plan conservation and facilitate anti-snake venom development.
เอกสารอ้างอิง :
Ratnarathorn, N., Harnyuttanakorn, P., Chanhome, L., Evans, S.E. and Day, J.J., 2019. Geographical differentiation and cryptic diversity in the monocled cobra, Naja kaouthia (Elapidae), from Thailand. Zoologica Scripta, 48(6), pp.711-726.
