Congratulations to Max Stockdale of the University of Bristol for winning one of our book tokens for his student talk at the Palaeontological Association Annual Meeting held in December. The book you requested will be winging its way to you shortly.
*Max T. Stockdale1, Michael J. Benton1, Mario Bronzati2, Marco B. de Andrade3 and Gavin T. Thomas4
1-University of Bristol, UK, 2-Bayerische Staatssammlung für Paläontologie und Geologie, Germany, 3-Pontifícia Universidade Católica do Rio Grande do Sul, Brazil, 4-University of Sheffield, UK
The Crocodylomorpha present a unique dichotomy in their diversity and morphological disparity through time. The stem group is limited to the Mesozoic, but is represented by a highly disparate range of ecomorphologies. Conversely the crown group is limited to amphibious ambush predators, but is represented by a much greater species richness than the stem group. Despite the abundance of the crown group, the crown-group Crocodylomorpha are represented by just 23 extant species. Does this pattern represent a true decline in disparity and diversity through time, or a more complex sequence of shifts within the group? Here we present a comparison of evolutionary rates among crown- and stem-group Crocodylomorpha in relation to morphospace occupation. The phylogenetic framework of these analyses is a new phylogeny of the Crocodylomorpha assembled using the matrix representation parsimony (MRP) method. This study finds support for extreme evolutionary stasis in several crocodylomorph clades. Diversity among the Crocodylomorpha appears to be closely linked with temperature, with decreasing diversity in the Cenozoic closely matching global cooling. Additional morphospace occupation by stem-group Crocodylomorpha relative to the crown group is occupied by taxa originating from two discrete adaptive radiations in the Mesozoic, with disparity otherwise remaining constant throughout the Mesozoic and Cenozoic.
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