Osteology and phylogeny of two fossil Crocodyliformes: Aplestosuchus sordidus, from the Cretaceous of Brazil, and Eocaiman cavernensis, from the Eocene of Argentina

Author(s)

Pedro Lorena Godoy

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
• Defense date: 2014-09-17

Examining board members

Max Cardoso Langer; Thiago da Silva Marinho; Estevan Eltink Nogueira

• Advisor: Max Cardoso Langer

Abstract

Crocodyliformes were much more diverse in the past than today. This incredible diversity is translated into a wide range of ecological niches occupied by these animals, many of which differ from the typical semiaquatic habit of the extant forms. In this context, the project developed during the MSc degree aimed to increase the knowledge about Crocodyliformes, with the study two fossil taxa, presented here in two separated parts. The first part includes the description of Aplestosuchus sordidus, a new species of Baurusuchidae (Mesoeucrocodylia), based on a nearly complete skeleton collected in deposits of the Adamantina Formation (Bauru Group, Late Cretaceous of Brazil). A phylogenetic analysis was performed to investigate the affinities of the new taxon, suggesting its sister-taxon relation to Baurusuchus albertoi, within Baurusuchinae. Additionally, the remains of a sphagesaurid crocodyliform were preserved in the abdominal cavity of the new baurusuchid, what would be the first time that a direct and unmistaken evidence of predation is recorded in fossil Crocodyliformes. This new finding confirms the important position that crocodyliforms had in the trophic structure of that environment. The second part of this work presents a re-evaluation of the anatomy of Eocaiman cavernensis (Crocodylia, Caimaninae) from the Middle Eocene of Argentina. This species, described by G. G. Simpson in 1933, is important due to its ubiquitous presence in phylogenetic studies of Caimaninae. Thus, its re-description aimed at revealing new anatomical information in order to clarify the relationships among taxa of this group. The new data was added to a previously published phylogenetic analysis and the results were discussed. In addition, the paleobiogeography and paleoecology of the genus Eocaiman was evaluated in the context of the Caimaninae. (AU)

• FAPESP's process: 11/16007-9 - Alpha-taxonomic review of the Baurusuchidae (Crocodyliformes, Mesoeucrocodylia) from Vale do Rio do Peixe formation (Bauru Group, Late Cretaceous), with the description of a new specimen from General Salgado-SP
• Grantee: Pedro Lorena Godoy
• Support Opportunities: Scholarships in Brazil - Master