Biogeography and macroevolutionary dynamics of Pilosa (Mammalia, Xenarthra) during the Great American Biotic Interchange

• Ano de defesa: 2024
• Autor(a) principal: Pimenta, Guilherme Borges
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Biogeografia; Biogeography; Dinâmicas macroevolutivas; Grande Intercâmbio Biótico Americano; Great American Biotic Interchange; Macroevolutionary dynamics; Pilosa; PyRate
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/59/59139/tde-18122024-163659/

Currently represented by anteaters and sloths, the group Pilosa is a part of the clade Xenarthra, one of the native mammal lineages from South America. Even though there are few extant species that have an almost restricted neotropical distribution, the study of their rich fossil diversity shows a range expansion to North America and the Caribbean islands. This process reached its height after the formation of the Panamanian Isthmus, driving the biogeographic event known as the Great American Biotic Interchange. The goal of this project was to investigate quantitatively what were the patterns of diversification for Pilosa and their dispersal during the Great American Biotic Interchange. For that, we gathered fossil occurrence data from online databases, with a curatorial review of these records to increase data quality. Afterward, we used models with a Bayesian framework from the PyRate package, characterized by their calculations taking into account the inherent bias from the fossil record, to estimate rates of diversification, dispersal, and sampling from the pilosan fossil record. Results showed a large number of occurrences for this group, mainly from countries like the United States, Ecuador, and Argentina, with more than 120 genera present. We found taxonomic, spatial and temporal biases while doing the curatorial review. From the macroevolutionary perspective, Pilosa went through different origination events in South America during the Early Miocene, the Late Miocene, and the Pleistocene. The major extinction events for the group in this continent happened during the Middle Miocene and the Pliocene. Dispersal from South America to North America began from the Late Miocene and drove the diversification of new taxa in the northern continent. The pattern of diversification for North America was high origination during the Late Miocene, a period of extinction during the Pliocene, and high origination rates in the Pleistocene. The patterns were discussed according to geologic, climatic, and vegetational changes observed in South America and the literature about the Great American Biotic Interchange. The impacts of the curatorial review in quantitative analyses were also discussed, by comparing results from data before and after the review. In general, an appropriate review of fossil occurrence data can deter false negatives and false positives while using models for macroevolutionary patterns. The next steps are the adjustment of methods and the elaboration of new hypotheses to be tested. We present here the most comprehensive quantitative results to date to show how Pilosa as a group behaved during the Neogene and the start of the Quaternary, with discussions that broaden the knowledge about South American fauna in a time of many changes and meetings of different faunas.