Banca de QUALIFICAÇÃO: VIRGINIA SILVA MACIEL

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : VIRGINIA SILVA MACIEL
DATE: 22/04/2024
TIME: 10:00
LOCAL: Videoconferência / Canal Youtube PPGG
TITLE:

Bone Histology of Smilodon Populator and Puma Concolor from the Equatorial Pleistocene of Brazil

KEY WORDS:

Quaternary, Felidae, Paleohistology, Paleoecology, Carnivora

PAGES: 29
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Geologia
SUMMARY:

Climate change over the last 50,000 years has had a significant impact on large mammals. Large felids have been one of the groups most affected by these fluctuations. To understand the possible causes of the extinction of some species, it is necessary to understand their paleobiology and compare it with living forms. In this study, we sampled the femoral histology of the largest saber-toothed felid in the Americas, Smilodon populator (MCC-868V), and a fossil specimen of Puma concolor (MCC991V), both from Quaternary deposits in Rio Grande do Norte, northeastern Brazil. We also estimated the body mass of the specimens analyzed and compared their bone compactness. The presence of EFS (External Fundamental System), generations of secondary osteons, and the presence of remodeled bone tissue indicate that both individuals had reached sexual maturity, although MCC-868V was a young adult at the time of death and MCC-991V a senescent adult. Slightly greater bone compactness was observed in P. concolor, which may be associated with its more advanced ontogenetic stage. The estimated mass for the P. concolor specimen (62 kg) is within the limits observed for the species, while the estimated mass for the S. populator specimen (157 kg) is lower than expected, even though the individual analyzed was an adult that had already finished growing. There are no histological indications that the specimen in question underwent restrictions throughout its growth, which suggests a truly smaller individual. Small size may be a trait selected in a local population due to the specific environmental and ecological conditions of the region or the presence of another species or subspecies of Smilodon. Both specimens analyzed showed growth with intense secondary remodeling, demonstrating a convergence with that observed in titanosaur dinosaurs and differing from what is known for most tetrapods. As no significant histological differences were found between the species analyzed, it is more likely that the extinction of Smilodon was actually more related to ecological aspects, such as a reduction in the availability of prey or preferred habitat.

COMMITTEE MEMBERS:
Presidente - 1283832 - ALINE MARCELE GHILARDI
Externo à Instituição - HERMINIO ISMAEL DE ARAUJO JUNIOR - UERJ
Externo à Instituição - MÁRIO ANDRÉ TRINDADE DANTAS - UFBA