Evolução morfológica no crânio de Lemuriformes (Primates:Strepsirrhini)

Abstract

Palavras-chave: Strepsirrhini, primatas, matriz P, deriva genética. 30 VI AbstractThe main goal of this study was to investigate the evolutionary processes responsible for Strepsirrhini cranial morphological evolution. Multidimensional morphological structures like the cranium can describe the amount of variance available to evolution. We used 27 landmarks and 39 euclidean distances between them to describe the variation in the cranium. We used a broad phylogenetic scaled com-5 parison of cranial P matrices representing 40 species of Strepsirrhini primates combined to a pair of Saguinus fuscicolis G and P to investigate the stability of variance structure along this lineage. Our results show a relative stability in the patterns of variance and covariance of the clade and that P matrices can be considered as surrogates to its underling G. We also report a high association between matrix similarity and phylogenetic distance. We investigated particular contributions of each trait to matrix 10 dissimilarity through a evolutionary perspective considering the main dietary shifts observed in the clade. Our results suggest that differences in observed patterns of variation can be attributed to characters with heterogeneity in the degree of stabilizing selection in the adult cranium and to differences in directional selection involved in chewing of specialized feeding behavior. Under the quantitative genetics theory lies an expectation for the evolution of average phenotypes that if populations have 15 diverged by random processes, patterns of within and between-taxon morphological variation should be proportional. In chapter 2 we tested the null hypothesis that genetic drift is a sufficient explanation to observed divergence in cranial multivariate means of 70 Strepsirrhini primates. We detected deviations from neutrality along the whole clade of Strepsirrhini and specially in more inclusive nodes. We argue that this deviations reflect important historical shifts in the evolution of the clade associated with 20 directional selection for size and in anatomical features related with diet. Keywords O formato da dissertaçãoEste documento foi organizado em introdução e conclusão gerais em português e dois capítulos em inglês preparados na forma de manuscrito de artigo científico. Acreditamos que essa escolha valoriza os esforços dedicados à dissertação por otimizar as etapas necessárias para divulgar o conhecimento gerado ao longo dos últimos três anos. As rotinas desenvolvidas pela equipe do Laborátório de Evolu-5 ção de Mamíferos (LEM) podem ser encontradas no material referente ao pacote evolqg no CRAN. Rotinas mais específicas a esta dissertação estão disponíveis para acesso público em minha conta VareciaRubra no GitHub 1 . Na introdução geral apresento o leitor ao sistema investigado levantando algumas das questões relevantes que fazem dos primatas Strepsirrhini um grupo interessante para estudos evolutivos. Nessa 10 sessão contextualizo o estudo de evolução morfológica e exponho detalhes dos fundamentos teórico-met...