Molecular Phylogenies Of Some Living Ranid Species

As one of the most diverse amphibian groups, ranid include over 700 species, which distribute all of the world, except southern South America and most of Australia. High morphological homoplasy among ranid makes traditional classification difficult and many taxonomic revisions treacherous without a reasonable phylogeny. Due to the wide distribution, Ranidae has great potential to trace the general evolutionary history. The pattern of biogeography and diversification of Asian ranid species can be understood by reconstructing their phylogenies. In present study, we used two nuclear genes (nu) and two mitochondrial genes (mt) to investigate the phylogenies of some living ranid species, and tentatively address the questions related to systematics and biogeography.The main results are as followed:1. Phylogeny about representative species of Chinese ranid was reconstructed using two nuclear data (tyrosinase gene and rhodopsin gene) and two mitochondrial gene partitions (12S and 16SrRNA). Presently, we suggested two subfamilies (Raninae and Dicroglossinae) for Chinese ranid species, and the genus Amolops should be retained in subfamily Raninae rather than elevating as one distinct subfamily Amolopinae; at the same time, genus Occidozyga should also be included in subfamily Dicroglossinae rather than as a distinct subfamily Occidozyginae. We proposed some taxonomical revision based on our molecular phylogenies. The comparison between previous studies and our data indicated that some genera proposed by Fei et.al. (1990) should be explored based on increased taxa and more other gene markers.2. Mainly based on our newly molecular data, we performed one comprehensive phylogenetic analysis on subfamily Raninae based on the sequences of approximately 2 kilobase (kb) from two mitochondrial (12S rRNA and 16S rRNA) and two nuclear (tyrosinase gene and rhodopsin gene) DNA fragments, in combination of previous published sequences from Genbank. Our combined data (mt+nu) well support a monophyletic subfamily Raninae consisting of tribe Stauroini and Ranini as proposed by Dubois (2005). Three genera Staurois, Rana, and Amolops within subfamily Raninae could not be rejected. Genus Pseudoamolops is invalid. The genus Amolops (sensu lato: Dubois, 1992) was paraphyletic and was the sister taxon to the genus Rana, which recovered to be monophyletic with low nodal support. Based on results here, eleven distinct lineages (including two distinct clades from North America) within tribe Ranini are recognized to reflect the phylogentic history and some taxonomic changes are proposed. Our results suggest that the abdominal sucker as one adaptation to torrents carried by different tadpoles of species has occurred multiple times independently during the evolutionary history of Raninae. By using a molecular clock-independent approach for inferring dating information from molecular phylogeny, we present here the molecular timescale for Raninae evolution. Lack of resolution and short branch length basal within Raninae indicate one possible rapid radiation after the collision between India and Eurasia. Two distinct dispersal events from Eurasia to the New World are supported.3. Based on partial sequences of 12S and 16S ribosomal RNA genes, we estimated phylogenetic relationships among the so-called brown frogs of East Asia. The phylogenetic trees showed monophyly of the brown frogs (Rana sauteri included), but with low resolving ability . All species of East Asian brown frogs with 24-chromosome constitute a monophyly (including Qinling group and northeastern Asia group), relative to Rana arvalis from Europe (2n=24). "Rana chensinensis" belonging to northeastern Asia group should be considered as another single species Rana dybowskii. Qinling group need further study, including Rana huanrenensis (Liaoning, China).