Molecular phylogeny of microhylid frogs (Anura: Microhylidae) with emphasis on relationships among New World genera
1 Department of Biology, University of Richmond, Richmond, VA 23173, USA
2 Amphibian and Reptile Diversity Research Center, Department of Biology, The University of Texas at Arlington, Arlington, TX, 76010, USA
3 Department of Environmental Sciences, University of Basel, Basel, CH-4056, Switzerland
4 Department of Biological Sciences, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX, 79968, USA
5 Herpetology Department, South Australian Museum, North Terrace, Adelaide, 5000, South Australia
6 Department of Terrestrial Vertebrates, Museum and Art Gallery of the Northern Territory, GPO Box 4646, Darwin, NT, 0801, Australia
7 Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Caixa Postal 199, Rio Claro, São Paulo, 13506-900, Brazil
BMC Evolutionary Biology 2012, 12:241 doi:10.1186/1471-2148-12-241Published: 10 December 2012
Over the last ten years we have seen great efforts focused on revising amphibian systematics. Phylogenetic reconstructions derived from DNA sequence data have played a central role in these revisionary studies but have typically under-sampled the diverse frog family Microhylidae. Here, we present a detailed phylogenetic study focused on expanding previous hypotheses of relationships within this cosmopolitan family. Specifically, we placed an emphasis on assessing relationships among New World genera and those taxa with uncertain phylogenetic affinities (i.e., incertae sedis).
One mitochondrial and three nuclear genes (about 2.8 kb) were sequenced to assess phylogenetic relationships. We utilized an unprecedented sampling of 200 microhylid taxa representing 91% of currently recognized subfamilies and 95% of New World genera. Our analyses do not fully resolve relationships among subfamilies supporting previous studies that have suggested a rapid early diversification of this clade. We observed a close relationship between Synapturanus and Otophryne of the subfamily Otophryninae. Within the subfamily Gastrophryninae relationships between genera were well resolved.
Otophryninae is distantly related to all other New World microhylids that were recovered as a monophyletic group, Gastrophryninae. Within Gastrophryninae, five genera were recovered as non-monophyletic; we propose taxonomic re-arrangements to render all genera monophyletic. This hypothesis of relationships and updated classification for New World microhylids may serve as a guide to better understand the evolutionary history of this group that is apparently subject to convergent morphological evolution and chromosome reduction. Based on a divergence analysis calibrated with hypotheses from previous studies and fossil data, it appears that microhylid genera inhabiting the New World originated during a period of gradual cooling from the late Oligocene to mid Miocene.