Systematics of new Dinosauriform specimens from the Upper Triassic (Carnian) Santa Maria Formation and phylogenetic implications of silesaurid mandible histology

• Grant number: 19/07510-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: August 01, 2019
• End date: January 31, 2020
• Field of knowledge: Biological Sciences - Zoology - Paleozoology
• Principal Investigator: Max Cardoso Langer
• Grantee: Gabriel Mestriner da Silva
• Supervisor: Sterling Nesbitt
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: Virginia Polytechnic Institute and State University, United States
• Associated to the scholarship: 18/24031-6 - Systematics of new Dinosauriformes specimens from the Upper Triassic (Carnian) of Cerro da Alemoa, Santa Maria-RS Formation and their importance for evolution and paleobiology of the first dinosaurs, BP.MS

Abstract

The phylogenetic relationships of silesaurids among Dinosauriformes are still controversial. They are usually recovered as sister-group of Dinosauria, whereas other topologies have placed Silesauridae within Ornithischia. Osteohistological analyses of dinosaurs have contributed to the comprehension of evolutionary significance of tooth attachment tissues in early dinosaurs. Tooth attachment is the nature of the attachment between a tooth and the jaw bone, which can be distinguished by teeth that are fused to the jaws by hard tissue (ankylosis) and those that are anchored by a periodontal ligament (gomphosis). The true thecodont condition, that is, presenting gomphosis, is found in mammals and crocodiles among extant amniotes. This state was shown to be plesiomorphic for the amniote lineage, though some groups show different attachment, such as silesaurids, that are ankylothecodont. This characteristic, that is recovered as synapomorphic for the group, was never assessed through histological sections, however. The osteohistological analyses of silesaurid tooth-bearing mandibles proposed in this research plan will clarify the true type of tooth ligament in the group, as well provide information about the properties of the associated tissues. Besides that, the plan also comtemplates postcranial material, which includes vertebrae, ribs, two right ilia, five femora, two left tibiae, one left fibula and pedal elements. These specimens will help shed light on the phylogenetic position of Silesauridae among Dinosauriformes, adding new anatomical information and reporting the first occurrence of silesaurids from the Brazilian Carnian. (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)

MESTRINER, GABRIEL; LEBLANC, AARON; NESBITT, STERLING J.; MARSOLA, JULIO C. A.; IRMIS, RANDALL B.; DA-ROSA, ATILA AUGUSTO STOCK; RIBEIRO, ANA MARIA; FERIGOLO, JORGE; LANGER, MAX. Histological analysis of ankylothecodonty in Silesauridae (Archosauria: Dinosauriformes) and its implications for the evolution of dinosaur tooth attachment. Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology, JUN 2021. (18/24031-6, 19/07510-0)

MESTRINER, GABRIEL; LEBLANC, AARON; NESBITT, STERLING J.; MARSOLA, JULIO C. A.; IRMIS, RANDALL B.; DA-ROSA, ATILA AUGUSTO STOCK; RIBEIRO, ANA MARIA; FERIGOLO, JORGE; LANGER, MAX. istological analysis of ankylothecodonty in Silesauridae (Archosauria: Dinosauriformes) and its implications for the evolution of dinosaur tooth attachmen. Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology, v. 305, n. 2, p. 393-423, FEB 2022. (19/07510-0, 18/24031-6)

MESTRINER, GABRIEL; MARSOLA, JULIO C. A.; NESBITT, STERLING J.; DA-ROSA, ATILA AUGUSTO STOCK; LANGER, MAX. Anatomy and phylogenetic affinities of a new silesaurid assemblage from the Carnian beds of south Brazil. JOURNAL OF VERTEBRATE PALEONTOLOGY, v. N/A, p. 26-pg., 2023-08-24. (18/24031-6, 20/07997-4, 21/14560-4, 19/07510-0, 22/00171-9)