For over 200 years, biogeographers have sought to understand the origins of biodiversity. The high species richness and endemism in peninsular India, especially within the Western Ghats (WG) and Eastern Ghats (EG) mountain ranges, have intrigued evolutionary biologists. This interest is also due to the fact that the Peninsular Indian Plate (PIP) is an ancient landmass — it was part of the supercontinent Gondwana approximately 200 million years ago (mya) and gradually drifted to its current position. So, where do all the organisms in peninsular India originate from? Were they there on the drifting PIP? Or did they disperse into India after the PIP collided with Eurasia? Were they diversifying on the drifting plate? Did geography, climate, or both influence it? Did biogeographic and diversification history also shape the diversity patterns?
We address these questions using centipedes as a model system in a molecular phylogenetic framework. Centipedes have a >420 million-year fossil history with more than 3000 described extant species. Our research on phylogeny and biogeography shows that scolopendrid centipedes have a deep evolutionary history in peninsular India (~100-80 million years), and they have Gondwanan origins. Multiple lineages have diversified in the drifting PIP, leading to endemic radiations, and some have even dispersed out of India. We also reconstructed their biogeography within the Western Ghats and found that the southern WG might have served as a refuge during Cretaceous volcanism, especially for wet forest-associated lineages.
Publications:
Dash, P., Roy, P., Joshi, J. 2026. Biogeography and cryptic diversity of the ancient centipede genus Digitipes (Scolopendromorpha) in South and Southeast Asia. bioRxiv.
Manivannan, M., Gurung, N., Edgecombe, G., Joshi, J. 2024. A Passage through India: The Biotic Ferry Model Supports the Build-up of Indo-Australian Biodiversity of an Ancient Soil Arthropod Clade. Journal of Biogeography, 51, 12, 2395-2411. doi.org/10.1111/jbi.14994 Covered by: The Hindu, Deccan Chronicles, Nature India, Deccan Herald
Bharti, D., Edgecombe, G., Karanth, P., Joshi, J. 2021. Spatial patterns of phylogenetic diversity and endemism in the Western Ghats, India: a case study using ancient predatory arthropods. Ecology and Evolution, 11, 3, 16499-16513. https://doi.org/10.1002/ece3.8119
Joshi, J., Karanth, P., Edgecombe, G. 2020. The Out-of-India hypothesis: Evidence from an ancient centipede genus, Rhysida (Chilopoda: Scolopendromorpha), from the Oriental Region, and systematics of Indian species. Zoological Journal of the Linnean Society 189, 3, 828–861. https://doi.org/10.1093/zoolinnean/zlz138
Joshi, J., and Edgecombe, G. 2019. Evolutionary Biogeography of the centipede genus Ethmostigmus from Peninsular India: Testing an Ancient Vicariance Hypothesis for Old World Tropical Speciation. BMC Evolutionary Biology 19: 41. https://doi.org/10.1186/s12862-019-1367-6 Popular article covering the paper On a trail with India's centipedes, 180 million years back in time
Joshi, J., and Edgecombe, G. 2018. Molecular phylogeny and systematics of the centipede genus Ethmostigmus Pocock, 1898 (Chilopoda: Scolopendromorpha) from Peninsular India. Invertebrate Systematics 32, 1316-1335. https://doi.org/10.1071/IS18030 Popular article covering the paper Moving continents created new centipede species
Joshi, J., and Karanth, P. 2013. Did southern Western Ghats of peninsular India serve as refugia for its endemic biota during the Cretaceous volcanism? Ecology and Evolution 3, 3275-3282. https://doi.org/10.1002/ece3.603
Joshi, J., and Edgecombe, G. 2013. Revision of the scolopendrid centipede Digitipes Attems, 1930, from India: reconciling molecular and morphological estimates of species diversity. Zootaxa 3626, 099–145. doi:http://dx.doi.org/10.11646/zootaxa.3626.1.5. Popular article covering the paper Looking beyond the hundred legs: finding new centipedes in India requires many tools
Joshi, J., & Karanth, P. 2012. The coalescent approach in conjunction with niche modeling reveals cryptic diversity among centipedes in the Western Ghats biodiversity hotspot of south India. PLoS ONE 7, e42225. https://doi.org/10.1371/journal.pone.0042225
Joshi, J., & Karanth, P. 2011. Cretaceous-Tertiary diversification among select Scolopendrid centipedes of South India. Molecular Phylogenetics and Evolution 60, 287-294. DOI: 10.1016/j.ympev.2011.04.024