A new genus and species of snake has been described from the north-eastern state of Mizoram.

The new genus, Smithophis, is named after eminent British herpetologist, Malcom A Smith for his immense contribution to Indian herpetology.

Between 1931 and 1943, Smith published three books on taxonomy of reptiles of the Indian subcontinent in the ‘Fauna of British India’ series. These three books are still the primary resource for those studying Indian reptiles, according to Varad B Giri of Foundation for Biodiversity Conservation, Pune.

The new genus was earlier considered as part of the genus Rhabdops, that was represented by only two species which were geographically separated by a considerable distance.

The Olive forest snake Rhabdops Olivaceous is found only in the Western Ghats and the bicoloured forest snake Rhabdops Bicolor is found only in northeast India.

The present study, based on DNA and morphology, established that both these species are not at all closely related, and what was once considered to be a single species from the northeast, are actually two distinct species.

The snakes from northeast India form a distinct lineage and are entirely different to those from the Western Ghats. As the species from the Western Ghats (Rhabdops Olivaceous) was historically described earlier than those from northeast India, it remains in the genus Rhabdops. The two species from the northeast have been assigned to a new genus – Smithophis. 

The new species lacks temporal scales (specific enlarged scales in the temporal region of the head). This character is extremely rare in snakes of this family, hence its name Smithophis Atemporalis or the Mizo rain snake. 

This snake is aquatic and is commonly seen in human dominated landscapes and forests as well. In Aizawl, the capital of Mizoram, this snake is commonly seen during the monsoons and frequents streams and other wet places, close to human habitation and is seen after rain showers.

Locals have known about this snake for ages and it is locally referred to as ‘ruahlawmrul', a rain-loving snake. The maximum recorded size of this supposedly non-venomous species is 655 mm (approximately 2.5 feet).

At present this species is known from various localities in Mizoram but it may have a wider distribution. This new species feeds on lizards and frogs, and lays eggs.

This discovery was a result of successful collaborative efforts between scientists from leading Indian and international institutes. The first author of this study, Dr. Giri collaborated with Dr. David Gower of the Natural History Museum, London, Dr. Abhijit Das of the Wildlife Institute of India, H T Lalremsanga of Mizoram University, Dr. Samuel Lalronunga of Pachunga University College, Aizawl, Ashok  Captain, a snake taxonomist from Pune and Dr. V. Deepak of the Indian Institute of Science, Bengaluru who is presently at the Natural History Museum, London.

The paper was published on May 9th, 2019, in the taxonomic journal Zootaxa. This new discovery highlights the importance of less explored habitats especially in the northeastern parts of India.