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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities

Lead Supervisor: Jason Head, Zoology

Brief summary: 
Combining fossil, molecular, and palaeoclimatic data will provide the first comprehensive analysis of the deep time origins of modern reptile diversity.
Importance of the area of research concerned: 
Reptiles (excluding Aves) are the most diverse and species-rich modern terrestrial vertebrates. Temporally-calibrated molecular phylogenies indicate a late Paleogene to early Neogene origin for many clades, and a dense fossil record suggests high Neogene diversity concomitant with establishment of an environmentally heterogenous, yet globally warmer, world. Despite these data, species richness of extant reptile clades, and the environmental correlates to their origins and diversification, remain poorly understood.
Project summary : 
The project will combine the fossil records of Neogene squamates, turtles, and crocodilians with published molecular phylogenetic data and palaeoenvironmental proxies from the rock record to reconstruct histories of richness in major reptile clades over the past 23 million years. Temporal calibration of phylogenetic trees will be compared with richness estimates from rarefaction and other estimation methods to reconstruct changes in relative and absolute species numbers in relation to patterns of regional and global climate change and tectonic events. This project will build on, and contribute to, existing public databases (e.g., Paleobiology Database), will access multiple museum collections, and will integrate molecular and fossil data to reconstruct the histories of living clades.
What will the student do?: 
The student will examine museum collections in the UK and abroad to collect occurrence data and will combine these observations with online databases to calibrate molecular phylogenetic topologies, calculate past richness at continental and regional scales, and compare results with quantified proxy data for temperature and precipitation as well as tectonically-driven episodes of geographic connectivity and isolation.
References - references should provide further reading about the project: 
Parham, J. F, P. C. J. Donoghue, C. J. Bell, T. D. Calway, J. J. Head, et al. 2012. Best practices for applying paleontological data to molecular divergence dating analyses. Systematic Biology, 61: 346-359.
Tolley, K.A., B.M. Chase, and F. Forest. 2008. Speciation and radiations track climate transitions since the Miocene Climatic Optimum: a case study of southern African chameleons. Journal of Biogeography,35(8): 1402-1414.
Santos, J.C., et. al. 2009. Amazonian amphibian diversity is primarily derived from late Miocene Andean lineages. PLoS Biology, 7(3), p.e1000056.
You can find out about applying for this project on the Department of Zoology page.
Dr Jason Head
Department of Zoology Graduate Administrator