Taxonomic assessment of fossil and living chelids (Testudines, Pleurodira) using geometric morphometrics, focusing on new material from the Tremembé Formation (Oligocene)

• Grant number: 25/16129-0
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: October 15, 2025
• End date: February 14, 2026
• Field of knowledge: Biological Sciences - Zoology - Paleozoology
• Principal Investigator: Pedro Lorena Godoy
• Grantee: Gustavo Gonçalves Barreiros
• Supervisor: Gabriel de Souza Ferreira
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Eberhard Karls Universität Tübingen, Germany
• Associated to the scholarship: 24/22761-8 - Description of new Chelidae (Testudines, Pleurodira) fossil material from the Tremembé Formation (Oligocene), with the proposal of a new species, BP.IC

Abstract

Commonly known as turtles, the Testudines are a group present in most fossiliferous locations, having an extensive fossil record starting in the Mesozoic. Turtles found in the Tremembé Formation, an important site for the understanding of Brazil's Oligocene fauna and environment in general, have been attributed to a single living species, Phrynops geoffroanus, which is unusual when taking into account the difference in habitat and the time passed since. This project aims to better classify and differentiate the fossil turtles from the Tremembé Formation, describing all fossils attributed to Testudines in the paleontological collection of Taubaté Natural History Museum Dr. Herculano Alvarenga, where the majority of the findings are deposited. The main tool to classify and describe the fossils analysed will be through morphological comparison with other fossil and living turtles, mainly from the Chelidae lineage and the Phrynops genus, but a crucial step to the project will be the use of two-dimensional geometric morphometric analyses to investigate the variance in a taxonomically relevant structure present in the carapace, the bridge strut scar. These methods will be applied during the BEPE Internship at the Senckenberg Centre for Human Evolution and Palaeoenvironment in the University of Tübingen in Germany, supervised by Dr. Gabriel de Souza Ferreira, a turtle expert with ample experience regarding geometric morphometric analyses. The expected results are to have at least one new turtle species described from the Tremembé Formation, helping in the evergrowing knowledge of the fossil record of Testudines and also the paleoenvironment during the Oligocene in Brazil.