New species of rain snake recorded in Mizoram

GUWAHATI

A team of researchers from Mizoram University and Guwahati-based biodiversity conservation group Help Earth have recorded a new species of rain snake from an elevated tropical forest in Mizoram.

The narrow-banded rain snake (Smithophis leptofasciatus) has been described in the latest issue of Taprobanica: The Journal of Asian Biodiversity.

The authors of the study — Lal Muansanga, Jayaditya Purkayastha, Vanlal Hruaia, Mathipi Vabeiryureilai, Lal Biakzuala, Ht Decemson, Hmar T. Lalremsanga, and Sanath C. Bohra — proposed ‘Ruahrul’ as the new-to-science snake’s Mizo name.

Rain snakes are so named because they become more active and visible during the rainy season.

The authors said the description was based on detailed morphological and molecular analyses of two collected specimens, along with observations of several live individuals. The new species is distinguished by its narrow, incomplete creamish-white or yellowish-lime transverse bands on a shiny black body — features that set it apart from its close relatives.

“Our study confirmed that this snake, previously identified as Smithophis bicolor, is a genetically and morphologically distinct species. It not only adds to the growing diversity within the genus Smithophis, but also redefines the distribution of previously known species,” Dr. Purkayastha, one of the corresponding authors, said.

The species name leptofasciatus is a Greek and Latin hybrid, meaning ‘narrow-banded’, referencing the snake’s distinctive dorsal markings. The narrow-banded rain snake was found inhabiting humid, shaded microhabitats near small streams in forests between 900 and 1,200 meters above sea level. Its semi-aquatic, nocturnal lifestyle was revealed through field observations during the monsoon.

A gravid female observed in captivity laid six eggs, providing rare reproductive data for this elusive group.

This is the third Smithophis species to be described from Mizoram after the Smithophis atemporalis and the Smithophis mizoramensis.

“The new species reinforces Mizoram’s importance as a biodiversity hotspot. The State plays a central role in the evolution and diversification of this genus,” said Dr. Lalremsanga, the co-author and head of the Developmental Biology and Herpetology Lab at Mizoram University.

The study recommended additional surveys and habitat assessments, as the narrow range and forest dependency of the narrow-banded rain snake suggest it may be vulnerable to habitat degradation.