Full text
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| Author(s): |
Rodrigo Araujo de Souza
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2014-09-12 |
| Examining board members: |
Miguel Trefaut Urbano Rodrigues;
Flavio de Barros Molina
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| Advisor: | Hussam El Dine Zaher |
| Abstract | |
Mesoclemmys vanderhaegei Bour, 1973 belongs to the family Chelidae, which presents the greatest variety of species of Testudines in Brazil. In spite of theories that suggest that the family might be monophyletic, there are still areas of doubt over the relationships between the taxa that belong to the Chelidae, and the possibility that various groups might prove to be paraphyletic. Mesoclemmys vanderhaegei has a large distribution range along the central and southern regions of the South American continent, and has been most specifically studied through an ecological perspective. A more detailed investigation of its taxonomic and phylogenetic characteristics is still both relevant and necessary, since the complex might represent multiple species. The present work aims, therefore, to study the populations of M. vanderhaegei from a phylogenetic and taxonomic perspective, looking to identify and characterize the populations in accordance with the evolutionary divergences that may be observed, thus justifying the subdivision of the complex into mutiple species. With this in mind, the populations of M. vanderhaegei were investigated using techniques of traditional and geometric morphometry, and a molecular phylogeny was proposed for the genus. The traditional morphometric data accounted for linear measurements of the plastron, carapace and head whilegeometric morphometric data were chosen as landmarks on the vertices of the scutes of the shells and on the dorsal and ventral midline of each specimen. Using samples of the majority of the populations of the species, and of all the species of the genus, three nuclear (RAG-2, R35 and c-mos) and two mitochondrial genes (12S and NADH) were sequenced for the study of the molecular phylogeny. Both the discriminant analysis of the linear measurements data and that of the landmarks separate the population found in the South of the Paraguay Basin (near the type locality of the species) from other Brazilian populations. The morphometric analyses show two other distinct populations: a population composed of specimens from Chapada dos Guimarães (MT), in the region of Cuiabá and one specimen from Bonito (MS); while the other population is represented by specimens taken from São João da Lagoa (MG), in the Basin of São Francisco. The resulting tree topology of theMaximum-Likelihood analysis derived from the molecular data suggests that M. vanderhaegei should be considered a polyphyletic group, that can be divided into four species: one species represented by the specimens from the South of the Amazonian Basin; another represented by the specimens from Montes Claros (MG), in the Basin of São Francisco; a third represented by the specimens from São João da Lagoa and the interior of São Paulo (Paraná Basin, sub Basin of the river Tietê); in addition to the one formed of the specimens close to the type locality. This would suggest, therefore, (1) that the distribution of Mesoclemmys vanderhaegei is restricted to the North of Argentina, Paraguay, and the West of Mato Grosso do Sul, until further studies are made to elucidate the extent to which the species has spread into Brazilian territory; (2) that the population of the Chapada dos Guimarães region and of the interior of Minas Gerais should be elevated to the category of species; (3) and that new studies must be carried out to determine the relationship between the populations of the Basin of Tocantins-Araguaia and Paraná with the other groups of the complex.! (AU) | |
| FAPESP's process: | 12/08639-8 - Morphological and Molecular variation of the Mesoclemmys vanderhaegei populations (Testudines: Chelidae) |
| Grantee: | Rodrigo Araujo de Souza |
| Support Opportunities: | Scholarships in Brazil - Master |