Spectacular Saga: Phylogenetics and phylogeography of the Indian spectacled cobra (Naja naja Linnaeus, 1758).

The spectacled cobra (Naja naja) is among the most iconic and clinically significant species, recognised as one of India's "big four" snakes responsible for a large number of snakebite-related fatalities. As a generalist with a near-countrywide distribution, N. naja exhibits considerable geographic variation in morphology, behaviour, and venom composition, yet its evolutionary history, phylogenetic diversity, and biogeographical origins remain poorly understood. To fill this knowledge gap, we sequenced nuclear and mitochondrial markers (n = 9) from 67 individuals spanning the major biogeographical regions of the Indian subcontinent. We reconstructed phylogenetic relationships under Bayesian inference and maximum likelihood frameworks, assessed genetic variation via p-distance estimates, haplotype networks, and evaluated lineage boundaries using species delimitation analyses. Phylogeographic structuring was further examined using a time-calibrated tree and ancestral-area reconstruction. Our results support an African origin for the genus Naja and support a Miocene dispersal of N. naja into South Asia. Unlike many widely distributed snakes, N. naja does not exhibit any evidence of phylogeographic subdivision within India, indicating that it is a largely panmictic mainland species. In contrast, Sri Lankan N. naja forms a genetically distinct clade, separate from mainland populations. Overall, our study offers new insights into the evolutionary history and phylogeographic diversity of the Indian spectacled cobra, underscoring the importance of investigating widely distributed species to better understand patterns of genetic variation.