In a remarkable feat of zoological detective work, a team of researchers has ended the 130-year disappearance of a snake species known only from a single specimen. The Cardamom Hills Earth-Snake, Rhinophis fergusonianus, has evaded the scientific community since its initial discovery in the late 19th century, with no subsequent sightings or specimens recorded until now.
This elusive serpent is part of the uropeltid family, commonly referred to as shieldtail snakes, known for their distinctive rostral shield separating their nasal scales and a large, shield-like terminal scute. These snakes are a significant component of the biodiversity in the Western Ghats of India—a global biodiversity hotspot.
The original holotype of R. fergusonianus was collected from the Cardamom Hills of Travancore, a region corresponding to the southern half of Kerala. The lack of precise locality information contributed to the difficulty in relocating this species in the wild.
The new research presents six specimens collected from low-elevation hills on both sides of the Palghat Gap, another biologically significant area in the Western Ghats. These new findings are backed by both external morphology and DNA-sequence data. Notably, this research also concludes that minor differences in scalation and colouration among the specimens can be attributed to individual or geographic variation rather than representing distinct species.
The revised diagnosis distinguishes R. fergusonianus from its closest relatives through various morphological traits, such as the number of ventral and subcaudal scales and unique colouration patterns. It also differs substantially in mitochondrial and nuclear DNA sequences from other Rhinophis species.
The habitats from which these specimens were collected suggest that R. fergusonianus may have a greater tolerance or preference for drier environments than its relatives. This adaptability could explain why the Palghat Gap, usually a significant biogeographic barrier for many species, did not isolate populations of R. fergusonianus. Observations of the newly documented specimens suggest that the species can tolerate some level of human disturbance and low-intensity agriculture found in mixed agricultural plots and near roadsides. However, the threat from road traffic and the uncertainty about the species’ population size and distribution raise conservation concerns.
The rediscovery of R. fergusonianus underscores the importance of continuous exploration and documentation in biodiversity-rich areas like the Western Ghats. The study also highlights the critical role of systematic and genetic analyses in correctly identifying and understanding species distribution. For the Cardamom Hills Earth-Snake, this rediscovery solves a long-standing zoological enigma and opens new chapters in the conservation and study of India’s rich herpetological diversity.
Gower, D. J., Narayanan, S., Deepak, V., Anvar, M. Y., & Das, S. (2023). Rediscovery and systematics of Rhinophis fergusonianus Boulenger, 1896 (Serpentes: Uropeltidae) from India’s Western Ghats. Zootaxa, 5374(1), 74–92. https://doi.org/10.11646/zootaxa.5374.1.4
