Systematics, Historical Biogeography & Diversification
Soil arthropod community
The research focuses on identifying evolutionary origins and relationships among taxa and then evaluating the role of geographic barriers, geo-climatic events, and phenotypic traits on their biogeographic and diversification patterns. We use multiple taxa to study these questions, like terrestrial and freshwater arthropods, large frugivorous birds, and woody plants in peninsular India. These multi-taxa comparisons have given some interesting insights into the evolution of biodiversity in Asia (Joshi and Karanth, 2011, 2012, 2013; Joshi and Edgecombe, 2019; Joshi et al., 2020; Joshi and Kunte, 2022, Bharti et al., 2023, Gopal et al., 2023).
We found that geographic and geo-climatic processes have played an important role in biogeography and diversification. We found ecologically adaptive and non-adaptive species pairs across taxa, suggesting that natural selection operates differently across multiple ecological axes. This emphasized the need to assess multiple ecological and evolutionary axes while examining diversification patterns and processes.
During this work, we also discovered many new species, primarily centipedes, in an integrative taxonomic framework (Joshi and Edgecombe, 2013, 2018, Joshi et al., 2020, Joshi and Agarwal, 2021).
This research broadly lies in the domain of macroecology and macroevolution. Some of the fundamental questions we would be tackling are the following:
1) Do diversification (speciation and extinction) rates vary across clades through time? Does that reflect in the disparity in clade diversity?
2) Do they show adaptive or non-adaptive divergence across multiple axes while diversifying?
3) What are the roles of geo-climatic and ecological processes on diversity dynamics?
Publications:
Bharti D., Pawar P. Y., Edgecombe G. D., Joshi J. 2023 Genetic diversity varies with species traits and latitude in predatory soil arthropods (Myriapoda: Chilopoda). Global Ecology and Biogeography doi: https://onlinelibrary.wiley.com/doi/10.1111/geb.13709
Joshi J., and Agarwal I. 2021. Integrative taxonomy in the Indian subcontinent - current progress and prospects. Journal of the Indian Institute of Science 101, 125–149 https://link.springer.com/article/10.1007/s41745-021-00244-2
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 Linnean Society, 189, 3, 828–861. https://doi.org/10.1093/zoolinnean/zlz138
Joshi J., & 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.
Joshi J., & 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
Joshi J., & 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., & 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.
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