摘要
The mitochondrial 16S rDNA sequences of 40species of cheilostome bryozoans including those of 24species newly determined were used to reconstruct thephylogenetic tree using neighboring-joining andmaximum-parsi- mony methods. By applying molecularclock technique on the basis of the appropriate phylogenyand the fossil record, the divergence times of the two maincheilostome groups, Anasca and Ascophora sensu stricto,were estimated. The results show that the molecularphylogeny of the higher taxonomic groups (superfamilies andhigher taxa) of cheilostome bryozoans is mostly in conflictwith the morphology-based phylogenetic trees; thedivergence of the extant groups of Anasca and those ofAscophora sensu stricto is estimated to have happened about263 Ma (Permian Guadalupian Epoch) and 183 Ma (EarlyJurassic), respectively.
The mitochondrial 16S rDNA sequences of 40 species of cheilostome bryozoans including those of 24 species newly determined were used to reconstruct the phylogenetic tree using neighboring-joining and maximum-parsimony methods. By applying molecular clock technique on the basis of the appropriate phylogeny and the fossil record, the divergence times of the two main cheilostome groups, Anasca and Ascophora sensu stricto, were estimated. The results show that the molecular phylogeny of the higher taxonomic groups (superfamilies and higher taxa) of cheilostome bryozoans is mostly in conflict with the morphology-based phylogenetic trees; the divergence of the extant groups of Anasca and those of Ascophora sensu stricto is estimated to have happened about 263 Ma (Permian Guadalupian Epoch) and 183 Ma (Early Jurassic), respectively.
基金
supported by the National Natural Science Foundation of China(Grant Nos.94725204&40202001)
Ministry of Science and Techonology(Grant No.G2000077702)
State Key Laboratory of Palaeobiology and Straitigraphy,Nanjing Institute of Geology and Palaeontology,the Chinese Academy of Sciences(Grant No.013115).
关键词
苔藓虫
生物学
分子结构
分歧时间
bryozoans
cheilostomes
16S rRNA
molecular phylogeny
phylochronology
