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Grinnell vs. Elton in deep and shallow time: Ecological drivers of lizards and snakes during the last 23 million years

Supervisor: Dr Jason Head

Project summary:

The project will combine the fossil records of Cenozoic squamates with paleoclimatic and other vertebrate fossil occurrences to determine the influences of environment, represented by quantified paleoclimatic proxy data, and biotic interactions, represented by fossil records of potential vertebrate predators and prey, in driving diversification. This project will build on, and contribute to, existing public databases (e.g, Paleobiology Database), will access multiple museum collections, and will combine palaeontological and spatial ecological methods to reconstruct niche occupation through time.

With over 10,000 extant species, Squamata (“lizards”, including snakes) represents one of the great vertebrate radiations. The clade is represented by a dense fossil record concomitant with histories of diversification and dispersal through the last 23 million years, and thus represents a key opportunity to elucidate the relative roles of environment (Grinnellian niches) and biotic interactions (Eltonian niches) in driving hyperdiverse clade diversification through deep time.

What the student will be doing:

The student will examine museum collections in the UK and abroad to collect occurrence data and will combine these observations with online databases to construct spatiotemporal patterns of diversity through time. The student will then compare histories with climatic and biotic records to determine relative influences of both on diversification. Niche modelling will be conducted for high-density fossil assemblages with coeval high-resolution paleoenvironmental data, and results will be compared with extant records to reconstruct temporal histories of niche occupation in different environments.

References:

Head, J. J. et al. 2009. Giant boid snake from the Paleocene neotropics reveals hotter past equatorial temperatures. Nature, vol. 457, pp. 715-717.
 
Parker, A.K., McHorse, B.K. and Pierce, S.E., 2018. Niche modeling reveals lack of broad-scale habitat partitioning in extinct horses of North America. Palaeogeography, Palaeoclimatology, Palaeoecology. https://doi.org/10.1016/j.palaeo.2018.07.017
 
Polly, P. D. & Head, J. J. 2015. Measuring earth-life transitions: Ecometric analysis of functional traits from late Cenozoic vertebrates. In P. D. Polly, Head, J. J. and Fox, D. L. (eds.), Earth-Life Transitions: Paleobiology in the Context of Earth System Evolution. The Paleontological Society Papers, vol. 21:21-46.