Comparação morfométrica entre crânios de híbridos e seus parentais Akodon cursor e Akodon montensis (Rodentia: Sigmodontinae)

• Ano de defesa: 2024
• Autor(a) principal: Teixeira, Júlia Andrade Frederico
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Biologia Animal; Centro de Ciências Humanas e Naturais; UFES; Programa de Pós-Graduação em Ciências Biológicas
• Palavras-chave em Português: Biologia evolutiva; Crânio; Morfometria craniana; Cricetidae; Morfologia (Animais); Akodon cursor; Evolução; Roedores; Akodon montensis; Evolutionary biology; Skull; Cranial Morphometrics; Zoologia
• Link de acesso: http://repositorio.ufes.br/handle/10/18167

This study investigates the cranial morphological differences between two species of rodents, Akodon cursor (Sigmodontinae: Rodentia) and Akodon montensis (Sigmodontinae: Rodentia), and their hybrids, highlighting the implications of hybridization for morphological inheritance. We analyzed a total of 122 specimens, including adults from both species and hybrids. Markings were made on the skulls of the specimens to obtain intersection points. From these points, we obtained the coordinates of the geometric landmarks, resulting in 38 distances. To examine and compare these distances, statistical methods such as ANOVA, Principal Component Analysis (PCA), Canonical Discriminant Analysis (CDA), Comparative Analysis of Complexity and Modularity Parameters, and Generalized Procrustes Analyses (GPA) were applied. The results indicated that the sampling effort was adequate to capture most of the variation in cranial measurements, as evidenced by the rarefaction curves, which showed stabilization of metrics after approximately 30 specimens for each group. Significant differences among the three groups were found in 23 of the 38 cranial distances (p ≤ 0.05), highlighting relevant morphological variations that likely reflect specific adaptations. Notably, A. cursor exhibited distinct phenotypic characteristics compared to the other groups, suggesting stronger selective pressures in its habitat. The findings reinforce previous studies indicating that hybridization contributes to an increase in morphological diversity, allowing for greater adaptability in varied ecological niches. The PCA revealed considerable morphological overlap between A. cursor, A. montensis, and the hybrids, suggesting phenotypic similarity among the groups. The CDA showed significant separation between the groups, with the intermediate position of the hybrids reflecting the phenotypic inheritance from both parents. The first discriminant function accounted for most of the observed variation. Additionally, the Comparative Analysis of Complexity Parameters, combined with the GPA, confirmed these results. These analyses indicated that hybrids not only retain characteristics from both parents but also position themselves morphologically between the two groups. The cranial morphological analysis revealed significant differences between A. cursor, A. montensis, and hybrids, suggesting distinct ecological adaptations and diverse evolutionary processes. Hybridization emerges as an important evolutionary process that generates morphological diversity and maintains genetic variation in contact zones. The observed differences among the three groups likely reflect different ecological strategies, with A. cursor and A. montensis resulting from distinct evolutionary trajectories, while hybrids explore a combination of resources from both parents. This study highlights the interaction between morphology, ecology, and evolution in Akodon species, underscoring the importance of hybridization in generating phenotypic and adaptive diversity