[关键词]
[摘要]
文中分析现生介形类 (Ostracoda) 4目 2 1科 2 9属的 18SrDNA部分序列 ,采用最大似然法 (ML)、邻接法 (NJ)和最大简约法 (MP) ,尝试构建介形类的分子系统树 ;结合介形类的形态特征和化石记录 ,主要对速足目(Podocopida)、丽足目 (Myodocopida)及其超科级分类阶元的系统发生关系进行探讨。 3种分析方法均支持形态学上Podocopida ,Myodocopida和海萤超科 (Cypridinacea)的界定 ;但对Podocopida目土菱介超科 (Bairdiacea)的系统地位提出质疑 ,该类群可能不是单系发生的自然类群。上述分析显示 ,Podocopida,Myodocopida,Platycopida和Halo cypridina组成一个单系群 ;介形类在目、超科、科和属的水平上可能发生过多次辐射分化
[Key word]
[Abstract]
We studied the phylogenetic relationships of 29 genera of 21 families using 18SrDNA partial sequences. Maximum parsimony (MP), maximum likelihood (ML) and neighbor joining (NJ) analyses combined with fossil records and morphological characters of Ostracoda were used to discuss the phylogenetic relationships among different lineages of ostracodes. Our results show that Podocopida, Myodocopida, superfamily Cypridinacea are monophyletic in all trees, whereas superfamily Bairdiacea is not. The monophyly of Myodocopida and Podocopida are strongly supported by molecular data. Our study also suggests that evolutionary radiation possibly occurred many times at different taxonomic levels of Ostracoda in history.
[中图分类号]
Q915.8
[基金项目]
科技部重大基础研究前期专项 (2 0 0 2CCA0 3 3 0 0 )，国家重点基础研究发展规划项目(G2 0 0 0 0 7770 2 )资助课题
