Chordata: Reptilia

Introduction:Reptiles, members of the Class Reptilia, constitute one of the most ancient and diverse groups of vertebrates, having originated during the Mesozoic era approximately 250 million years ago.While numerous lineages have gone extinct due to major natural events and climatic shifts, extant reptiles display remarkable adaptations that enable their survival in a wide range of terrestrial and aquatic ecosystems, excluding only the polar and subpolar regions.Key characteristics of reptiles include a scaly integument, ectothermic (cold-blooded) metabolism, and typically a three-chambered h e a r t , w i t h t h e n o t a b l e e x c e p t i o n o f crocodilians, which possess a four-chambered heart akin to that of birds and mammals.In India, modern reptiles are categorized into three taxonomic orders: Order Crocodylia (crocodiles & gharial), Order Testudines (turtles and tortoises), and Order Squamata (lizards and snakes).India's diverse physiographic and climatic zones ranging from arid deserts and coastal plains to dense forests and montane ecosystems harbor a rich reptilian fauna.Notably, biodiversity hotspots such as the Western Ghats, Eastern Himalayas, and parts of the Indo-Burma region support high species richness and endemism.Unlike birds and mammals, many reptiles demonstrate narrow habitat preferences and restricted distributions, often tied to specific microhabitats or ecological niches.This ecological specialization renders them particularly vulnerable to environmental disturbances.Major threats to reptilian b i o d i v e r s i t y i n I n d i a i n c l u d e h a b i t a t fragmentation and degradation, illegal wildlife trade, pollution, road mortality, and the intensifying impacts of climate change.Given their ecological significance as both predators and prey, and their sensitivity to environmental c h a n g e s , r e p t i l e s s e r v e a s i m p o r t a n t bioindicators.Enhanced efforts in field research, habitat protection, and community-inclusive conservation programs are crucial to ensure the long-term survival of India's reptilian diversity.Diversity:Out of nearly 12,370 species of extant reptiles recorded worldwide till December 2024, 833 species and subspecies (6.33%) are distributed in India, which comprises 16 subspecies (Uetz et al., 2025 and the present compilation).With the advancement of molecular taxonomy, the actual species