Naja kaouthia Lesson, 1831 is a common and widely distributed venomous snake in South and Southeast Asia. The species is regarded as having a high degree of phenotypic plasticity and variability in venom composition across its distributional range. Limited information is available on this complex species in the context of population studies and systematics, and population studies, particularly in northeast India, are scarce. In this study, we explore sexual dimorphism and potential intraspecific morphological variation within the population of N. kaouthia from Mizoram, northeast India, while also aiming to enrich the systematic data and reappraise the matrilineal genetic diversity across various geographical locations. Sexually dimorphic traits are identified in both meristic and morphometric characters. We hypothesise that male-biased sexual selection for success in male-male rivalry may be the cause of sexual dimorphism in head size and shape in this species. Our mitochondrial phylogeny (16s, cytb and cox1) recovered two well-supported South Asian and Southeast Asian clades within N. kaouthia with a wide genetic divergence (4.4%) between them. Our study also revealed intraspecific variation in the hood markings from the examined population, which warrant more studies to determine whether these variants are randomly distributed or reflect geographic structure and lineage differentiation.
Genetic diversity, Intraspecific variation, Molecular phylogenetics, Monocled cobra, Morphometric analysis
