Diversität und Disparität der Anomodontia (Tetrapoda, Therapsida) über das Permisch-Triassische Aussterbeereignis
Final Report Abstract
The greatest mass extinction in Earth's history at the end oft he Permian (~252.5 Ma) had a major impact on marine and terrestrial ecosytems alike. My project investigated diversity patterns in Anomodontia, an extinct group of therapsid synapsids that represented the dominant herbivores of their time, through time but with special focus on the end-Permian extinction. This study applied a number of different approaches including traditional paleontological, descriptive and phylogenetic components as well as a number of quantitative elements to investigate the evolutionary history, as well as phylogenetic and morphological diversity patterns within this group. First results 1. provided a robust taxonomic and phylogenetic framework using modern systematic approaches, 2. produced evidence for a widespread ecological disturbance in the extinction’s aftermath, and 3. delivered indications that Antarctica served as refuge for anomodonts and terrestrial tetrapods in general from some of the effects of the end-Permian mass extinction. Data analyses of the diversity and disparity subprojects are at their final stages and still ongoing, but initial results include: 1. Phylogenetic diversity estimates generally confirm the results of taxonomic analyses, but they do not support a mid-Permian event among anomodonts, suggesting that it is likely a relic of a biased fossil record; 2. Anomodont disparity is highest near the clade’s origin, and declines steadily thereafter. A disparity drop at the Permian-Triassic boundary does not differ significantly in magnitude from preceding and succeeding declines but instead appears to be part of the long-term trend, indicating that richness and disparity were decoupled throughout anomodont history. This research sheds new light on our understanding of the impact of the end-Permian extinction event on terrestrial ecosystems. Future research will be directed towards expanding research on this ideal model group to better understand extinction but also survival patterns across the most severe extinction event in Earth’s history, but also to apply the same methodologies and approaches of this study to other tetrapod groups and at a broader taxonomic scale.
Publications
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(2010) The Triassic dicynodont Kombuisia (Synapsida, Anomodontia) from Antarctica, a refuge from the terrestrial Permian-Triassic mass extinction. – Naturwissenschaften 97: 187-196
Fröbisch, J., Angielczyk, K. D., and Sidor, C. A.
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(2011) A comprehensive taxonomic revision of Dicynodon (Therapsida: Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy. – Journal of Vertebrate Paleontology, Memoir 31(S1): 1-157
Kammerer, C. F., Angielczyk, K. D., and Fröbisch, J.
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(2011) On dental occlusion and saber teeth. – Science 331: 1525-1528
Fröbisch, J.
