Evolution of skull shape in extinct and extant turtles

• Grant number: 19/02086-6
• Support type: Scholarships in Brazil - Master
• Effective date (Start): June 01, 2019
• Effective date (End): February 28, 2021
• Field of knowledge: Biological Sciences - Zoology
• Principal Investigator: Max Cardoso Langer
• Grantee: Guilherme Hermanson Souza
• Home Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Ecomorphological studies associate morphological (e.g. body size) and ecological (e.g. diet) patterns, being vertebrates widely used as models. Among them, turtles (Testudines) have been little explored in this regard. Turtles occupy a great diversity of environments, from fully aquatic (freshwater and marine) to terrestrial, which allows them access to different sorts of resources. Similarly, their wide phenotypic variation of skull shape is noteworthy, supposedly related to different environmental pressures along their evolutionary history. In order to test the correlations between morphology and ecology, geometric morphometrics can be an important tool and, when analysed on a phylogenetic background, allows to reconstruct the different evolutionary paths that shaped the turtle skull. The project will investigate the evolution of the skull shape in Testudines using virtual models of skull generated by computed tomography and 3D geometric morphometrics. With this method, the 3D aspects of the skull are analysed altogether, allowing a more accurate capture of the specimens geometry. The aim of this work is to evaluate whether ecological features of turtles such as diet and habitat influence their skull shape. Additionally, we expect to do a more accurate estimate of the ecology of the analysed fossil taxa, previously inferred mainly by 2D (e.g. photographs) and qualitative data. (AU)