New country record of globally threatened Uperodon assamensis (Amphibia: Microhylidae) from Bangladesh, with an updated global distribution and taxonomic analysis

We report a new country record of Uperodon assamensis (a globally threatened species, previously considered endemic to India), with a taxonomic description, from south-central Bangladesh. The newly recorded specimen was identified by having a distinct yellowish dorsal vertebral stripe, an absent or non-visible tympanum, rounded and moderately large choanae, an absence of vomerine teeth, an oval tongue with rounded tips and papillae, and a distinct supratympanic fold that extends from the eyes' posterior corner to the supra-axillary region. The boxplot of the morphometric measurements of the type specimens from distant geo-locations reveals substantial variability in snout–vent length, head width, head depth, tibia length, and axillary–groin distance. In contrast, the eye diameter, internarial distance, eye-to-nostril distance, and eye-to-snout distance show less variability. Besides this, we compiled its known occurrence records and confirmed the current global distribution in three South Asian countries: India, Nepal, and Bangladesh. This study contributes to understanding the geographic distribution of U. assamensis and intraspecific morphological and morphometric diversity, highlighting the importance of continued field surveys in uncovering the biodiversity of underexplored regions in South Asia.