基于16S rRNA序列的角蟾科部分属间系统关系

采用最大似然法(ML法)、最大简约法(MP法)、邻接法(NJ法)对来自角蟾科Megophryidae(Anura)8属17种及外群2种共25条400bp左右的线粒体16S rRNA序列进行系统发育关系分析。结果表明，用于分析的所有角蟾科物种形成两大支，第一支包括Megophrys，Brachytarsophrys和Atympanophrys，第二支包括Leptobrachium，Leptolalax，Scutiger，Oreolalax和Vibrissaphora。支持将角蟾科划分为两大类群，即第一支属于Megophryini族．第二支属于Leptobrachiini族。根据分子钟模型初步推测两类群问的分歧时间大致为14．2～18．7百万年前。在Megophryini族中，基因树的拓扑结构不支持Atympanophrys建立后的Megophrys为单系；而在Leptobrachiini族中，Leptolalax为一有效属，其系统发生较早。

Phylogenetic Relationships of Megophryid Genera (Anura:Megophryidae) Based on Partial Sequences of Mitochondrial 16 S rRNA Gene

Phylogenetic relationships of 8 genera of Megophryidae (Anura) were discussed based on 25 partial sequences of mitochondrial 16S rRNA gene.Maximum likelihood,maximum parsimony,and neighbor joining analyses were performed on the dataset.The ingroup was divided into two major clades,Clade 1 and Clade 2,on the gene tree.Clade 1 included Megophrys,Brachytarsophrys and Atympanophrys,while Leptolalax,Oreolalax,Scutiger,Leptobrachium and Vibrissaphora belonged to Clade 2.This met the result of morphological study.It was primarily estimated that the divergence age of two clades occured 14.2-18.7 million years ago.The topology of Clade 1 did not support Megophrys to be a monophyletic group.In Clade 2,Leptolalax was believed to be a valid genus and was the taxon that occurred much early.