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Dr Jason James Head

Dr Jason James Head

University Lecturer and Curator of Vertebrate Palaeontology

Jason Head is accepting applications for PhD students.

Museum Room G.20
Office Phone: +44 (0)1223 (7)65387



I am a broadly-trained vertebrate paleontologist. I received my BSc in biology from the University of Michigan in 1995, and my PhD in geology (with a concentration in vertebrate paleontology) from Southern Methodist University in 2002. I held a National Science Foundation Postdoctoral Fellowship in Biological Informatics at the Smithsonian Institution and Queen Mary, University of London from 2002-2005, and was faculty at the George Washington University, University of Toronto, and University of Nebraska-Lincoln prior to joining the Department of Zoology in 2015.

Museum- and field research are fundamental components of my research and teaching, and I have 25 years of natural history museum experience ranging from specimen preparation and conservation, database development, public education and outreach, to curation and staff management. My field research has spanned the Triassic to Pleistocene of the Americas, Africa, and South Asia. My current focus is on the Neogene of East Africa.

Research Themes


Research Interests

My research interests align along two axes, one primarily ecological and one primarily evolutionary developmental: 1) the evolution of modern vertebrate clades, focusing on the relationship between fauna and environment during the Paleogene and Neogene; and 2) the evolution of regulatory genetic networks and novel developmental mechanisms in the origins of vertebrate body forms as evidenced from anatomy. Although the questions I address and the methods I employ are not taxon-specific, my focus is on reptiles because they are diverse, important components of modern ecosystems, possess a dense fossil record during the last 65 million years, and exhibit extraordinary plasticity in body form and ecophenotype, including axial elongation, limblessness, and the evolution of shells. My work integrates phenomic data, as quantified and qualified skeletal anatomy derived from field and museum studies, with molecular, environmental, and paleoclimate datasets. 

The newest component of my research is the integration of ecometric trait data from fossil vertebrates with modern records to help forecast biotic responses to anthropogenic climate change as a component of taxon-free conservation paleobiology.

Key Publications

Barnosky, A. D., E. A. Hadly, P. Gonzalez, J. J. Head, P. D. Polly, A. M. Lawing, J. T. Eronen, D. D. Ackerly, K. Alex, E. Biber, J. Blois, J. Brashares, G. Ceballos, E. Davis, G. P. Dietl, R. Dirzo, H. Doremus, M. Fortelius, H. W. Greene, J. Hellmann, T. Hickler, S. T. Jackson, M. Kemp, P. L. Koch, C. Kremen, E. L. Lindsey, C. Looy, C. R. Marshall, C. Mendenhall, A.S Mulch, A. M. Mychajliw, C. Nowak, U. Ramakrishnan, J. Schnitzler, K. D. Shrestha, K. Solari, L. Stegner, M. A. Stegner, N. Chr. Stenseth, M. H. Wake. Z. Zhang. 2017. Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems. Science, 355 (6325). doi: 10.1126/science.aah4787

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

P. D. Polly, and J. J. Head. 2015. Measuring Earth-Life Transitions: Ecometric analysis of functional traits from Late Cenozoic Vertebrates. The Paleontological Society Papers, 21: 21-46.

Head, J. J., G. F. Gunnell, P. A. Holroyd, J. H. Hutchison, and R. L. Ciochon. 2013. Giant lizards occupied herbivorous mammalian ecospace during the Paleogene greenhouse in Southeast Asia. Proceedings of the Royal Society of London, Series B. doi:10.1098/rspb.2013.0665.

Lawing, A. M., J. J. Head, and P. D. Polly. 2012. The ecology of morphology: the ecometrics of locomotion and macroenvironment in North American snakes. Pp. 117-146 in J. Louys (ed), Palaeontology in Ecology and Conservation. Springer, New York.

Müller, J., C. Hipsley, J. J. Head, N. Kardjilov, A. Hilger, M. Wuttke, and R. R. Reisz. 2011. Limbed lizard from the Eocene of Germany reveals amphisbaenian origins. Nature, 473, 364–367.

Parham, J. F, P. C. J. Donoghue, C. J. Bell, T. D. Calway, J. J. Head, P. A. Holroyd, J. G. Inoue, R. B. Irmis, W. G. Joyce, D. T. Ksepka, J. S. L. Patańe, N. D. Smith, J. E. Tarver, M. van Tuinen, Z. Yang, K. D. Angielczyk, J. Greenwood, C. A. Hipsley, L. L. Jacobs, P. J. Makovicky, J. Müller, K. T. Smith, J. M. Theodor, R. C. M. Warnock, M. J. Benton. 2012. Best practices for applying paleontological data to molecular divergence dating analyses. Systematic Biology, 61 (2): 346-359.

Müller, J., T. Scheyer, J. J. Head, P.M. Barrett, P. Ericson, D. Pol, and M. R. Sanchéz-Villagra. 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), 107:2118-2123

Ksepka, D. T., M. J. Benton, M. T. Carrano, M. A. Gandolfo, J. J. Head, E. J. Hermsen, W. G. Joyce, K. S. Lamm, J. S. L. Patané, M. J. Phillips, P. D. Polly, J. L. Ware, R. C. M. Warnock, M. van Tuinen, J. F. Parham. 2011. Synthesizing and databasing fossil calibrations: divergence dating and beyond. Biology Letters, doi: 10.1098/rsbl.2011.0356. 

Wilson, J. A., D. Mohabey, S. Peters, and J. J. Head. 2010. Predation upon hatchling sauropod dinosaurs by a new basal snake from the Late Cretaceous of India. PLOS Biology. 8:1–5 doi:10.1371/journal.pbio.1000322.g005.

Head, J. J., J. I. Bloch, A. K. Hastings, J. R. Bourque, E. A. Cadena, F. A. Herrera, P. D. Polly, and C. A. Jaramillo. 2009. Giant boid snake from the Paleocene neotropics reveals hotter past equatorial temperatures. Nature, 457:715-717

Head, J. J., P. M. Barrett, and E. J. Rayfield. 2009. Neurocranial osteology and systematic relationships of Varanus (Megalania) prisca Owen (Squamata, Varanidae). Zoological Journal of the Linnaean Society of London, 155:445-457.

Reisz, R. R., and J. J. Head. 2008. Turtle origins out to sea. Nature, 456:450-451. 

Other Publications

Head, J. J., and J. Müller. In Press. Squamate reptiles from Kanapoi: Faunal evidence for hominin paleoenvironments. Journal of Human Evolution.

DeMar, D., J. Conrad, J. J. Head, D. Varricchio, and G. Wilson. 2017. A new Late Cretaceous iguanomorph from North America and the origin of New World Pleurodonta (Squamata, Iguania). Proceedings of the Royal Society B, 284: 20161902. doi: 10.1098/rspb.2016.1902.

Head, J. J., K. Mahlow, and J. Müller. 2016. Fossil calibration dates for molecular phylogenetic analysis of snakes 2: Caenophidia, Colubroidea, Elapoidea, Colubridae. Palaeontologia Electronica, 19.2.2FC: 1-21.

Moreno-Bernal, J., J. J. Head, and C. Jaramillo. 2016. Fossil Crocodilians from the High Guajira Peninsula of Colombia: Neogene faunal change in northernmost South America. Journal of Vertebrate Paleontology, doi: 10.1080/02724634.2016.1110586.

Gunnell, G. F., A. J. Winkler, E. R. Miller, J. J. Head, A. N. El-Barkooky, M. A. Gawad, W. J. Sanders, and P. D. Gingerich. 2016. Small vertebrates from Khasm El-Raqaba, late Middle Miocene, Eastern Desert, Egypt. Historical Biology, 28:59-171.

Head, J. J. 2015. Fossil calibration dates for molecular phylogenetic analysis of snakes 1: Serpentes, Alethinophidia, Boidae, Pythonidae, Palaeontologia Electronica, 18(1):1-17.

Cuff, A., M. Randau, J. J. Head, S. Pierce, J. J. Hutchison, and A. Goswami. 2015. Big Cat, small cat: Reconstructing body size evolution in living and extinct Felidae. Journal of Evolutionary Biology, 28:1516-1525. doi: 10.1111/jeb.12671.

Barrett, P. M., D. C. Evans, and J. J. Head. 2014. A re-evaluation of purported hadrosaurid dinosaur specimens from the ‘middle’ Cretaceous of England. Pp. 96-107 in In D. Eberth and D. C. Evans (eds.) Hadrosaurs, Indiana University Press. 

Conard. J., M. T. Carrano, and J. J. Head. 2014. Unusual soft-tissue preservation of a Crocodile Lizard (Squamata, Shinisauria) from the Green River Formation (Eocene). The Anatomical Record, 297:545-559. doi: 10.1002/ar.22868.

Head, J. J., A. Rincon, C. Suarez, C. Montes, and C. Jaramillo. 2012. Evidence for American interchange during the earliest Neogene: Boa from the Miocene of Panama. Journal of Vertebrate Paleontology, 32:1328-1334.

Mohabey, D., J. J. Head, and J. A. Wilson. 2011. A new species of the snake genus Madtsoia from the Cretaceous of India and its paleobiogeographical implications. Journal of Vertebrate Paleontology, 33:588-595. 

Sanders, K. L., Mumpuni, A. Hamidy, J. J. Head, and D. J. Gower. 2010. Phylogeny and divergence times of filesnakes (Acrochordus): Inferences from morphology, fossils and three molecular loci. Molecular Phylogenetics and Evolution, 56:857-867. 

Bajpai, S, and J. J. Head. 2008. An early Eocene palaeopheid snake from Vastan Lignite Mine, Gujarat, India. Gondwana Geological Magazine, 22:85-90. 

Head, J. J., and C. J. Bell. 2008. Snakes from Lemudong'o, Kenya Rift Valley. In: L. Hlusko (ed.), Stratigraphy, Paleontology, and Paleoecology of the Lemudong'o Site, Kenya. Kirtlandia, 56:177-179. 

Ambrose, S. H., C. J. Bell, R. L. Bernor, J.-R. Boisserie, C. M. Darwent, D. Degusta, A. Deino, N. Garcia, Y. Haile-Selassie, J. J. Head, L. J. Hlusko, F. C. Howell, M. D. Kyule, F. K. Manthi, E. M. Mathu, C. M. Nyamai, M. Pickford, H. Saegusa, T. A. Stidham, and M. A. J. Williams. 2008. The Paleoecology and Paleogeographic Context of Lemudong’o Locality 1, a Late Miocene Terrestrial Fossil Site in Southern Kenya. Kirtlandia, 56:38-52