Revisiting the snakes of Bangladesh: a systematic review of species diversity and distribution patterns

Bangladesh is a country of rich biodiversity, including herpetofauna, across diverse ecosystems. This study reviews snake diversity and distribution patterns in Bangladesh, identifying 141 species in the existing literature. However, we confirmed the presence of 89 species based on documentation in literature, research-grade data in online repositories, and verified photographs on social media. Among them, the family Colubridae comprises 35%, followed by Elapidae (26%), Natricidae (13%), and others. Regarding envenomations, 70% of the species are non-venomous and 30% are venomous. Three species ( Acrochordus granulatus , Boiga westermanni , and Dieurostus dussumieri ) were considered regionally extinct in the absence of sightings in the past five decades. Sixteen species were deleted due to unreliable reports or misidentifications, while Ahaetulla sahyadrensis and Rhabdophis helleri were added. Additionally, we hypothesize that 33 species may inhabit Bangladesh, considering their ecological distribution. We illustrated the geographical distribution patterns of confirmed species using kernel density estimation (KDE), identifying the mixed evergreen forests in the southeast and northeast and the mangrove forests in the southwest as densely populated habitats. This study enhances the understanding of snake diversity and distribution in Bangladesh and underscores the need for further research and conservation efforts to prevent species extinction.