Relações filogenéticas entre espécies do gênero Lycalopex (Mammalia, Canidae) inferidas com o uso de marcadores do DNA mitocondrial

• Ano de defesa: 2011
• Autor(a) principal: Favarini, Marina Ochoa
• Orientador(a): Eizirik, Eduardo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul; Porto Alegre
• Palavras-chave em Português: ZOOLOGIA; FILOGENÉTICA; CARNÍVOROS; DNA
• Link de acesso: http://hdl.handle.net/10923/5320

South America harbors the greatest diversity of canids (Mammalia, Carnivora, Canidae) worldwide, containing representatives of six genera and a total of 10 species. The fossil record indicates that canid representatives have colonized South America from North America during the Great American Biotic Interchange, ca. 2. 5 million years ago (Mya). Current hypotheses postulate between one and four independent canid invasions to South America, with the exact number being a recurrent topic for controversy. Several morphological and molecular studies have attempted to unravel the phylogenetic relationships among canids, but many uncertainties remain. This is particularly the case of the South American fox clade corresponding to genus Lycalopex, which comprises six extant species. Recent studies have indicated that this genus has undergone a very rapid radiation ca. one million years ago, which underlies the historical difficulty in resolving the phylogeny of these canids. In this context, the present study aimed to reconstruct the phylogenetic relationships among the species comprised in this genus, as well as to date their divergences. We used multiple segments of the mitochondrial DNA (mtDNA), encompassing a total of 6000 bp. Several different phylogenetic methods were employed, with all trees converging on the same inter-specific topology. We included multiple individuals from each species, allowing us the evaluation of the monophyly of each of them (including L. sechurae, tested here for the first time). All species formed well-supported monophyletic clusters, corroborating their recognition as taxonomic entities. The single exception to this pattern was the identification of two L. vetulus individuals sampled in São Paulo state, Brazil, which bore mtDNA sequences that clustered within the L. gymnocercus clade. This result could indicate that L. gymnocercus is expanding its range in to São Paulo state, or else that these two species may by hybridizing in the wild. Molecular dating analyses indicated that the genus began its radiation ca. 1 Mya, corroborating earlier studies which reported a very recent origin for this canid group. The most basal species was L. vetulus, followed by L. sechurae. The most internal cluster contains L. culpaeus and L. fulvipes, with our results indicating that they diverged from each other ca. 390,000 years ago. On the basis of the reconstructed phylogenetic patterns, we discuss hypotheses regarding the biogeography of this genus, aiming to understand the history of its rapid diversification process in the Neotropics.