| Summary: | Tesis doctoral leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología.-- Fecha de lectura: 29-06-2012 Modern anurans (frog and toads) have a long evolutionary history of more than 200 million years, having undergone an extraordinary phylogenetic and ecological diversification, which gave rise to the 6,000 species currently recognized. They exhibit a variety of morphological, ecological and behavioural adaptations that allowed them to inhabit many different environments, across every continent (except Antarctica) and most continental islands. Early studies on morphology made important contributions towards understanding the evolutionary history of frogs. Later on, the analysis of sequence data, and the development of powerful and sophisticated probabilistic methods of inference provided substantial advance in the phylogeny of frogs. In the last decade, the application of molecular phylogenetic techniques allowed resolving some of the controversial issues regarding higher-level relationships among living frogs, and currently, we have a reasonably well-defined portrait of the frog tree of life. Yet, many important issues still remain under debate. Most studies agree on a monophyletic origin of the Anura, and four major lineages are generally recognized (Discoglossoidea, Pipoidea, Pelobatoidea, and Neobatrachia), along with two basal genera (Leiopelma and Ascaphus) of uncertain placement. Here, a sequence data set combining complete mitochondrial genomes and nine nuclear loci was used to estimate a molecular phylogeny of frogs and tackle long-standing contentious questions. First, the relative phylogenetic position of Leiopelma and Ascaphus, two genera that have traditionally been considered basal within Anura, was addressed. Second, new sequence data was generated for Pipoidea, aiming to discriminate among competing hypotheses for the relationship between this group and Discoglossoidea, as well as to elucidate the internal phylogeny of the family Pipidae. Taking advantage of ...
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