Patterns of diversification in terrestrial vertebrate evolution

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The fossil record of vertebrates, with preservation of complex*skeletons and teeth provides the best evidence of evolutionary dynamics across*large temporal scales for investigating the mechanisms and conditions that led*to the modern ecosystems. The origin and initial stages of*amniote evolution represent the start of a great*chapter in earth's history, the conquest of land by vertebrates. Within 6*million years of their first appearance*311 Million year ago (Ma), we see rapid evolutionary radiations that extend to*the present, and include extant squamates, turtles, crocodiles,*birds, mammals, and many extinct relatives, including dinosaurs.***Ongoing research in vertebrate paleontology including the anatomy,*taxic diversity, and phylogenetic relationships of early amniotes will continue*to be part of the present proposal because new discoveries can have major*impacts on our understanding of vertebrate evolution. Here I propose to combine*these ongoing investigations with studies of ecological diversity. I therefore*plan to evaluate evolutionary changes in both taxic and ecological diversity*through time as reflected by their reconstructed feeding behaviour. First, I*will integrate for the first time calibrated phylogenetic analyses across*clades for a better understanding of patterns of diversification and evolution*within communities. I will then examine morphological variation (disparity),*including dental and mandibular diversity in comparative, phylogenetic and*temporal contexts in order to track the ecological diversification of early*amniotes as they evolved to access formerly unoccupied ecospaces and novel food*resources. Morphometric analyses of variation in tooth and jaw shape, and size*in successive Paleozoic communities will be organized into 8 time bins that*extend from the Late Carboniferous (311 Ma) to the Middle Permian (272 Ma). In*order to understand the ecological diversity present in these Paleozoic*communities I plan to quantify variation in tooth and jaw morphology, and*deduce the dietary preferences in each taxon. Several other variables,*including cranial and postcranial data may be included in the total disparity*analyses. Since extant reptiles show morphological similarities to Paleozoic*terrestrial amniotes, squamates can be used as extant model systems. My*research group will develop for the first time ecomorphological models that can*be applied to early amniotes, and test the hypothetical importance of dietary*shifts in the ecological diversification of amniotes. The novel use of combined ecological*and taxic diversity patterns represents one of the transformative ways in which*we approach this paleobiological research program. These analyses will shed new light on the community structure and evolution of early amniotes during the*initial stages of terrestrial vertebrate evolution.***** * 0* 0* 1* 413* 2440* University of Toronto at Mississauga* 40* 25* 2828* 14.0* * * * *** * Normal* 0* * * * * false* false* false* * EN-US* JA* X-NONE* * * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * **** /* Style Definitions */*table.MsoNormalTable* {mso-style-name:"Table Normal";* mso-tstyle-rowband-size:0;* mso-tstyle-colband-size:0;* mso-style-noshow:yes;* mso-style-priority:99;* mso-style-parent:"";* mso-padding-alt:0cm 5.4pt 0cm 5.4pt;* mso-para-margin:0cm;* mso-para-margin-bottom:.0001pt;* mso-pagination:widow-orphan;* font-size:12.0pt;* font-family:Cambria;* mso-ascii-font-family:Cambria;* mso-ascii-theme-font:minor-latin;* mso-h