# Systematics and evolutionary history of proterosuchian archosauriforms

Ezcurra, Martin D. (2015). Systematics and evolutionary history of proterosuchian archosauriforms. University of Birmingham. Ph.D.

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## Abstract

The evolutionary history of archosauromorphs is of particular interest because it includes the origins of two of the best-known and most distinctive extant tetrapod groups: crocodylians and birds. In this thesis, the anatomy, taxonomy and systematics of the Permo-Triassic non-archosaur archosauromorphs are revised. A revision of the Permo-Triassic archosauromorph record indicates that only four Permian species are known and there are three valid proterosuchid species immediately after the Permo-Triassic boundary in South Africa. Analyses of cranial ontogenetic variation in $$Proterosuchus$$ $$fergusi$$ found that ontogenetic modification events (e.g. heterochrony) may have been key drivers of the evolution of the general shape of the skull at the base of Archosauriformes. A comprehensive quantitative phylogenetic analysis recovered a polyphyletic “Prolacertiformes”, restricted the taxonomic content of Proterosuchidae to only six species, Erythrosuchidae was composed of eight nominal species, and $$Euparkeria$$ $$capensis$$ was found as the sister-taxon of the clade that includes proterochampsians (doswelliids + proterochampsids) and archosaurs. The results obtained here suggest that the evolutionary history of the archosauriforms during the Early Triassic can be subdivided into a first phase characterized by the short-lived “disaster-clade” Proterosuchidae and a second phase that witnessed the initial morphological and probably palaeoecological diversification of the group.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Supervisor(s):
Supervisor(s)EmailORCID
Butler, RichardUNSPECIFIEDUNSPECIFIED
Sansom, IvanUNSPECIFIEDUNSPECIFIED
Licence:
College/Faculty: Colleges (2008 onwards) > College of Life & Environmental Sciences
School or Department: School of Geography, Earth and Environmental Sciences
Funders: None/not applicable
Subjects: Q Science > QE Geology
Q Science > QH Natural history
URI: http://etheses.bham.ac.uk/id/eprint/6033

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