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| Author(s): |
Mariela Cordeiro de Castro
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2010-02-24 |
| Examining board members: |
Max Cardoso Langer;
Flávio Alicino Bockmann;
Jorge Ferigolo
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| Advisor: | Max Cardoso Langer |
| Abstract | |
This work presents the comparative description of the skull, postcranium and osteoderms of the Dasypodini (Xenarthra, Cingulata) MNRJ 552-V, collected in the quaternary deposits of Gruta de Itaporanga, Sorocaba-SP, Brazil. The skull was CT scanned and compared to those of extant taxa of all three Dasypodidae subfamilies, while the postcranium was compared to that of Dasypus novemcinctus. Given that MNRJ 552-V was originally described as Propraopus punctatus, it was compared to fossils (especially composed of osteoderms) attributed to this genus in paleontological collections of Brazil and Argentina. In order to define the relations of the described specimen to other Dasypodini, a phylogenetic study was performed. Along with MNRJ 552-V, the ingroup comprises five operational taxonomic units (OTUs), including two extant species of Dasypus, two specimens attributed to P. grandis, as well as part of the type material of Dasypus sulcatus Lund, 1842 from Lagoa Santa-MG, the latter solely analyzed based on the literature. The outgroup was defined based on previous phylogenetic studies and includes Stegotherium tesselatum and Cabassous tatouay. The osteoderms, which are skeletal parts historically relevant to Cingulata systematics, were also fundamental to differentiate the ingroup OTUs in the analysis. The single most parsimonious tree obtained with an exact search suggested that MNRJ 552-V is more closely related to the extant Dasypus species. Accordingly, it is preferable to attribute that specimen to D. punctatus Lund, 1840, following the original designation of the species. The sister clade of Dasypus, which consists of a polytomy with three other OTUs, was assigned to the genus Propraopus, once it includes material referred to its type species (P. grandis). Therefore, the OTU Dasypus sulcatus should be treated as Propraopus sulcatus. The polytomy that forms the Propraopus clade highlights the problem in differentiating P. sulcatus and P. grandis, as previously pointed by many authors. (AU) | |