Phylogenetic Diversity and Biogeography of South Asian Reptiles

South Asia harbours one of the world’s most diverse reptile assemblages, shaped by a complex interplay of plate tectonics, palaeoclimate and geomorphological barriers. Molecular phylogenetic studies have revealed deep divergences among lineages that trace back to the Cretaceous separation of the Indian Plate and its subsequent collision with Eurasia. The Western Ghats of peninsular India and the Sri Lankan highlands emerge as centres of endemism, with multiple in situ radiations in gekkonid lizards, agamid dragons and uropeltid snakes. Time-calibrated phylogenies indicate that some groups originated in Gondwanan Gondwana, while others colonised the subcontinent via Eocene land bridges or overwater dispersal. Climatic shifts during the Miocene and Pliocene fragmented tropical forests into montane “sky islands”, driving allopatric speciation and shaping present-day distributions. Integrating multilocus sequence data with ancestral area reconstruction has begun to resolve colonisation routes, identify cryptic diversity and inform conservation priorities in this biodiversity hotspot.

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Phylogenetic Diversity and Biogeography of South Asian Reptiles publication trend

The graph below shows the total number of articles in phylogenetic diversity and biogeography of south asian reptiles across all publications each year (not limited to Nature Index journals).

Technical terms

Phylogenetic diversity: A measure of evolutionary divergence among species in a community, reflecting total branch lengths on a phylogenetic tree.

Biogeography: The study of the spatial distribution of organisms through geological time, driven by dispersal, vicariance and environmental change.

Endemism: The ecological state of being unique to a defined geographic location, such as an island or mountain range.

Clade: A group of organisms that includes an ancestor and all its descendants on a phylogenetic tree.

Time-calibrated phylogeny: A phylogenetic tree in which branch lengths are scaled to absolute time, often by using fossil or geological calibrations.

Ancestral area reconstruction: A computational method to infer the most likely geographic origin of ancestral lineages based on phylogenetic relationships and species distributions.

References

1. Diversifying on the Ark: multiple new endemic lineages of dwarf geckos from the Western Ghats provide insights into the systematics and biogeography of South Asian Cnemaspis (Reptilia: Squamata). 动物学研究 (2021).
2. Three new cryptic species of South Asian Cnemaspis Strauch, 1887 (Squamata, Gekkonidae) from Karnataka, India. Vertebrate Zoology (2022).
3. Dwarfs of the fortress: A new cryptic species of dwarf gecko of the genus Cnemaspis Strauch, 1887 (Squamata, Gekkonidae) from Rajgad fort in the northern Western Ghats of Maharashtra, India. Evolutionary Systematics (2021).