Indian scientists have discovered the first new species – and genus – of snake in the Western Ghats for more than a century.
Proahaetulla antiqua – a “visually unusual” vine snake – diverged from other vine snakes around 26 million years ago, and thus throws new light on their origin and evolution in Asia, they say.
The research was led by Ashok Kumar Mallik and Kartik Shanker from the Indian Institute of Science in Bangalore, and their findings are reported in the journal PLOS One.
India has around 300 species of snake, both venomous and otherwise, and on average three new ones have been recorded each year for the past decade. However, discoveries in the Western Ghats, a mountain range that stretches along the country’s west coast, have been rare.
Proahaetulla antiqua was found in the Agasthyamalai hills. It is a member of the Ahaetuliinae clade, which currently comprises the arboreal snake genera Ahaetulla, Dryophiops, Dendrelaphis and Chrysopelea, which are distributed in South and Southeast Asia.
The Ahaetuliinae family consists of mildly venomous snakes.
Comparing the structural features of the new snake with those of other closely related vine snakes, Mallik and colleagues identified a host of distinct features that set it apart. It is 1189 millimetres long, and has a uniformly bright green body, showing a yellow to light green underside mid body.
When threatened, it reveals inter-scalar skin, coloured with a consecutive series of black and white bars that converge towards the head.
It has a greenish yellow tongue, 20 maxillary (upper) teeth, and three postocular scales lying directly behind and in contact with the eye.
“Divergence dating reveals that the new genus is ancient, dating back to the Mid-Oligocene, and is one of the oldest persisting monotypic lineages of snakes in the Western Ghats,” the researchers write.
“This discovery adds to the growing list of ancient lineages endemic to the Agasthyamalai hills and underscores the biogeographic significance of this isolated massif in the southern Western Ghats.”