Phylogeny And Taxonomy Of Megophrydae

Megophryidae represents one of the most diverse groups within extant Archaeobatrachia, occurring in tropical and semitropical mountains distributed in south China and southeast Asia. It comprises about 140 species belonging to 10 genera,two subfamilies. The validity of some genura and subfamilies remains controversy.Phylogenetic relationships of frogs within the family Megophryidae were investigated using mitochondrial 12S and 16S rRNA genes collected from 43 Megophryid species representing 9 genera. In addition, we downloaded 12 same part sequences of 12S and 16S for 11 species of Megophryidae from Genbank Phylogenetic analyses of maximum parsimony, maximum likelihood and Bayesian analyses are performed using MEGA 4.0,DAMBE,PAUP4.0 b10,PhyML version 3.0,MrBayes3.0b4. Our work here supports the monophyly of Megophryidae, as well as three subfamilies: Megophryinae,Leptolalaginae and Leptobrachiinae.The genura Megophrys (sensu lato) should be split into three different genera: Megophrys (sensu stricto), Xenophrys and Atympanophrys. There exist two cryptic genura in Xenophrys. The subgenus Paramegophrys (Paramegophrys) should be upgraded to genus rank and Paramegophrys(Leptolalax) attributed to genus Leptobrachella. The subgenura Scutiger(Scutiger) and Scutiger(Aelurophryne) are invalid.The paper suggested that the Hengduan Mountains in southwestern China might be the centre of diversification of Megophryidae, modern distribution pattern of the family had gradually formed from north, particular the Hengduan Mountains, to the south in Asia since the early Tertiary (about 65 Ma ago).A phylogeny of all 17 species in genus Oreolalax is reconstructed based on 21 morphological characters from adult specimens, skeleton specimens, tadpoles and eggs. Based on the evolutional tendency of the morphological characters on phylogenetic tree, it is proposed that the evolution of tympanum, tympanic annulus, columella, spoon-like cartilage and the web between toes reflect the habit changes from aquatic to terrestrial. It is suggested that southern parts of Hengduan Mountains might be the oringin centre of Oreolalax and the western mountains of Sichuan province and the middle-southern part of Hengduan Mountains might be the distribution and differentiation centre of Oreolalax. The tendency of expansion of Oreolalax was probably from southwest (south Hengduan Mountains) to northeast (middle Hengduan Mountains and Mountains around Sichuan basin). The formation and differentiation of present Oreolalax might be related with the Himalayas orogeny.