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B322: Evolution of axial skeleton diversity in reptiles (Lead Supervisor: Jason Head, Zoology)

Supervisors: Jason Head (Zoology) and Robert Asher (Zoology)

Importance of the area of research:

The axial skeleton is a key innovation in the diversification of form and function in vertebrates, and developmental studies have revealed molecular mechanisms that pattern vertebral and rib anatomy in model taxa. The roles of regulatory genetics and other developmental mechanisms in driving macroevolutionary innovations in axial skeletal morphology across phylogeny are not well understood, however, and the evolution of skeletal diversity is unknown for many vertebrate lineages. Reptiles are a species-rich vertebrate group with over 20,000 living taxa. They possess a wide range of axial specializations from turtle shells to the vertebral columns of snakes and birds, but the evolution of axial anatomies across Reptilia has not been comprehensively examined in the context of developmental mechanisms or environmental histories.

Project summary:

This project will reconstruct evolutionary patterns of anatomical change and innovation in the axial skeleton in all modern reptile groups as well fossil taxa such as dinosaurs, pterosaurs, and marine reptiles. Phylogenetic comparative methods will be used to compare these patterns with developmental data from model taxa, allowing the inference of evolutionary histories of regulatory gene function in the origin of new axial morphologies. Fossil data will be used to place results in the contexts of radiation, extinction, and environmental change through deep time.

What the student will do:

The student will collect data on vertebral and rib morphology in modern and fossil reptiles through examination of museum collections, including the use of Computed-Tomographic (C-T) and surface scanning of specimens. The student will use geometric morphometric analysis of anatomical shape to quantify changes in the axial skeleton both within and between taxa, and will use phylogenetic comparative methods to reconstruct ancestral states, calculate rates of change, and to examine historical patterns of anatomical and developmental change. The student will use results of these approaches to formulate hypotheses on the history and mechanisms underlying the diversification of reptile axial skeletal morphology.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Head, J.J. & Polly, P. D. 2015. Evolution of the snake body form reveals homoplasy in amniote Hox gene function. Nature, vol. 520, pp. 86-89, doi: 10.1038/nature14042

Böhmer, C., Rauhut, O.W.M. & Wörheide, G. 2015. Correlation between Hox code and vertebral morphology in archosaurs. Proceedings of the Royal Society B, vol. 282. Pp. 20150077, di: 10.1098/rspb.2015.0077

Müller, J., Scheyer, T., Head, J.J., Barrett, P.M., Ericson, P., Pol, D. & Sanchéz-Villagra, M.R. 2010. The evolution of vertebral numbers in recent and fossil amniotes: The roles of homeotic effects and somitogenesis. Proceedings of the National Academy of Sciences of the United States of America (PNAS), vol. 107, pp. 2118-2123, doi: 10.1073/pnas.0912622107

Follow this link to find out about applying for this project

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