速足目主要类群系统发育的分子证据

文章基于速足目现生主要类群18S rDNA、28S rDNA和COI基因序列,采用贝叶斯法、邻接法和最大简约法,尝试构建速足目的分子系统树;结合形态特征和化石记录,主要对速足目各超科级分类阶元的系统发育关系进行探讨。结果表明,速足目现生超科Bairdiacea、Darwinulacea、Cypridacea和Cytheracea均为单系群,支持形态学上关于上述4个超科的的界定;3种基因均支持形态学上Darwinulacea和Cypridacea具有较近的亲缘关系的观点。18S rDNA序列分析在较显著水平上支持Darwinulacea和Bairdiacea为姐妹群,Darwinulacea可能从Bairdia-cea中的一支演化而来;Bairdiacea和Darwinulacea组成的分支是Cypridacea的姐妹群,支持将三者合并为Bairdio-copina亚目的观点;Cytheracea是Cypridacea(Darwinulacea Bairdiacea)的姐妹群,可提升为Cytheracopina亚目。

MOLECULAR PHYLOGENY OF MAJOR GROUPS OF PODOCOPIDA

The 18S rDNA, 28S rDNA and COI gene sequence data were used to estimate the phylogenetic relationships of four superfamilies of Podocopida. Maximum-parsimony (MP), Bayesian and neighbor-joining (NJ) analyses combined with fossil records and morphological characters of Ostracoda were used to discuss the phylogenetic relationships among four major lineages of Podocopida. Cytheracea, Cypridacea, Darwinulacea and Bairdiacea were monophyletic groups in all trees. The closer relationship between Cypridacea and Darwinulacea is strongly supported by molecular data. The 18S rDNA data suggest that Darwinulacea evolved from within the Bairdiacea, and the two superfamilies together form the sister group of Cypridacea, further suggesting that Podocopida can be divided into two suborders: Bairdicopina (including Cypridinacea, Bairdiacea and Darwinulacea) and Cytheracopina (Cytheracea).