The Western Ghats are home to a remarkable diversity of floral and faunal groups, with a high degree of endemism. Geckos are no exception to this phenomenon and many groups with diverse evolutionary origins inhabit these mountains.
However, the only endemic gecko genus in the Western Ghats is Dravidogecko — a small-sized lizard restricted to the wet forests in the mid to high elevations. They are distributed from Wayanad district in the north up to Tirunelveli district in the south along the length of the southern Western Ghats.
Until recently, only one species (Dravidogecko anamallensis that was described in 1875 by German-born British Zoologist Albert Günther) was recognized under this genus, which was perceived to be widespread across the Western Ghats.
A team of scientists set out to study these enigmatic geckos to understand their diversity and evolutionary origins. Fieldwork and sampling across the Western Ghats revealed that there were not one but at least six new species hiding in plain sight, under the name Dravidogecko anamallensis. The study also shows how the ancestors of Dravidogecko may have colonized peninsular India around 58 million years ago, potentially island-hopping their way into the subcontinent.
This work further attributes the diversification of these geckos into different species to aridification events that started during the late Miocene epoch (ca. 9 million years ago).
The six new species have been named Dravidogecko septentrionalis, D. janakiae (in honour of Dr. Janaki Ammal, a botanist from Kerala), D. tholpalli, D. meghamalaiensis, D. douglasadamsi (in honour of British author and satirist, Douglas Noel Adams) and D. smithi (in honour of British herpetologist Malcolm Arthur Smith).
These geckos are chiefly nocturnal and are great climbers, according to a press statement. They prefer to occupy tree trunks and abandoned buildings amidst their natural habitat.
All these different species inhabit the same ecological niche across their distribution and therefore display very few morphological differences. However, DNA-based molecular analyses can easily tell them apart.
Their findings were recently published in the international taxonomic journal, Zootaxa.