Macroevolutionary and ecological patterns of the morphological evolution of akodontine rodents

• Autor(a) principal: Rafaela Velloso Missagia
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/38682; https://orcid.org/0000-0001-9279-8045
• topic: Morphological evolution; Sigmodontinae; Comparative methods; Functional morphology; Stable isotopes; Trophic niche; Macroevolution; Zoologia; Morfologia (animais); Sigmodontinae; Isótopos estáveis

The evolutionary history of Akodontini is characterized by a successful radiation in South America. They are diverse in adaptive types and morphology, and are particularly rich in soricine insectivorous species. However, macroevolutionary and ecological patterns remain mostly unexplored in the group. We collected a comprehensive morphological dataset and hair samples of Akodontini species for functional, ecological and macroevolutionary analyses, and the results were compared between the four main lineages of Akodontini. Through a comparative morphological description, we show that cranial characteristics of Blarinomys breviceps reflect its fossorial habits and insectivorous diet. We provided new isotopic data for 47 species of Akodontini rodents, representing the first ecological information of this kind for some of them. The stable isotopes dataset was analyzed from a macroecological perspective, and gave insights about the trophic niche diversity inside the group. The distribution of some species on the bivariate isospace corroborated stomach content data from the literature, and the clades whitin the tribe occupy the bi-plot in a similar way, although differing in trophic diversity. When analysing the influence of diet on morphology, we found that functional traits of the jaw reflect feeding ecology in akodontine rodents. While herbivorous species present higher mechanical advantages and bite forces to process plant material, insectivorous species favour speed over strength of the jaw apparatus, more useful for catching live prey. The oldest lineage within the tribe is also the most diverse in ecology and cranial morphology. Although not taxonomically rich, it comprises a set of species that appear to have acquired a specialized morphology corresponding, in part, to different feeding habits. In general, historical contingency seems to have more influence on the patterns of disparity in size and shape in Akodontini, with feeding ecology having a secondary role. We found evidence for a pattern of convergent evolution in four Akodontini lineages, which present a similar skull shape apparently in response to specialization to an insectivorous diet.