New materials of Clevosaurus (Rhynchocephalia, Sphenodontia) from the Triassic of Southern Brazil: approaches about ontogenetic variation and endocranial anatomy

• Grant number: 20/06819-5
• Support Opportunities: Scholarships in Brazil - Master
• Start date: October 01, 2020
• End date: January 31, 2022
• Field of knowledge: Biological Sciences - Zoology - Paleozoology
• Principal Investigator: Annie Schmaltz Hsiou
• Grantee: Lívia Roese Miron
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Clevosauridae (Lepidosauria, Rhynchocephalia) was a clade of Sphenodontia considerably abundant during the early Mesozoic. Clevosaurus represents the most diverse and broadly distributed genus among the group, with species ranging from the Upper Triassic to the Lower Jurassic. In the deposits of the Upper Triassic of South America (Rio Grande do Sul, Brazil), two species of Clevosaurus are known: C. brasiliensis (Caturrita Formation, Riograndia Assemblage Zone (AZ), Norian), a small sphenodontian with several known specimens, and C. hadroprodon (Santa Maria Formation, Hyperodapedon AZ, Carnian), the oldest sphenodontian from Gondwana and the oldest in the world to present a fully acrodont dentition. With the exception of one study that investigated the ontogeny of the mandible of C. brasiliensis, the ontogenetic variation of Clevosaurus remains little known. Moreover, the endocranial anatomy of rhynchocephalians is a topic not yet investigated, and the existence of specimens of Clevosaurus that preserve the braincase allows its study. From the reevaluation of specimens from both species deposited in Brazilian paleontological collections, as well as from the description of a new specimen of C. brasiliensis and the comparison with other fossil sphenodontians from the Mesozoic, this project aims to contribute to the knowledge of the anatomy and ontogenetic variation patterns of the Clevosaurus from Southern Brazil, as well as to the understanding of its phylogenetic relationships. Also, it will be described the endocranial anatomy of C. brasiliensis and of the only living sphenodont, Sphenodon punctatus. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ROESE-MIRON, LIVIA; JONES, MARC EMYR HUW; FERREIRA, JOSE DARIVAL; HSIOU, ANNIE SCHMALTZ. Virtual endocasts of Clevosaurus brasiliensis and the tuatara: Rhynchocephalian neuroanatomy and the oldest endocranial record for Lepidosauria. Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology, v. N/A, p. 24-pg., 2023-03-23. (20/06819-5, 19/14153-0)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

MIRON, Lívia Roese. Endocranial anatomy of Rhynchocephalia (Diapsida, Lepidosauria): ontogenetic variation and allometric relationships in Clevosaurus brasiliensis (Upper Triassic, Brazil) and Sphenodon punctatus. 2022. Master's Dissertation - Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC) Ribeirão Preto.