Phylogeography, speciation and demographic history: Contrasting evidence from mitochondrial and nuclear markers of the Odorrana graminea sensu lato (Anura, Ranidae) in China.

ABSTRACT

Understanding the process of speciation and the factors driving the geographical distribution patterns of species is of great interest in ecology and evolutionary biology. Herein, we investigated the phylogeographic patterns, speciation, demographic history and genetic structure of the widespread endemic Odorrana graminea sensu lato in Southern China and adjacent areas. A total of 439 specimens from 68 localities were sequenced and analyzed for both mitochondrial (12S and 16S rRNA) and nuclear markers (RAG-1 and ten microsatellite loci). Phylogenetic analyses of the concatenated mtDNA data revealed five major highly divergent lineages within the O. graminea sensu lato in Southern China, and these divergent lineages were highly concordant with five geographical regions. The nuclear data showed a discordant genetic structure compared to the mtDNA lineages (Clades A, B, and C) for O. graminea sensu stricto, with an admixed pattern in the RAG-1 data and two structure clusters in the microsatellite data. The species delimitation analyses, based on three methods, supported the species status of Odorrana zhaoi and Odorrana rotodora, and revealed the existence of putative cryptic species in the O. graminea sensu stricto. In addition, one statistically significant gene flow event was detected from Clade B to Clade C based on mtDNA and RAG-1 data, and the microsatellite data suggested gene flow within the O. graminea sensu stricto. Bayesian skyline plotting analyses and ecological niche modeling supported demographic and range expansions during the LGM for Clades A and C of the O. graminea sensu stricto. In addition, ecological niche models suggested the existence of ecological divergence among the three Clades (Clades A, B and C) of the O. graminea sensu stricto. The intense uplifting of the Qinghai-Tibetan Plateau, the Quaternary climate oscillations, and drainage changes may have driven the speciation, genetic structure and phylogeoraphic patterns of the O. graminea sensu lato.