Phylogeny of Devonian Lycopsids Inferred from Bayesian Phylogenetic Analyses  

作　　者：XUE Jinzhuang 

机构地区：[1]The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China

出　　处：《Acta Geologica Sinica(English Edition)》2011年第3期569-580,共12页地质学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(nos:40830211, 40802003);the China Postdoctoral Science Foundation (no:20070420245)

摘　　要：To investigate the phylogeny of early lycopsids,cladistic analyses using both parsimony and Bayesian approaches are presented,with a data matrix of 33 morphological characters across 25 taxa. The resulting parsimony and Bayesian trees showed overall similarities in tree topologies.In the Bayesian tree,the Protolepidodendrales and the heterosporous lycopsids are recognized as two monophyletic groups,and within the latter group,the Isoetales sensu lato forms a subclade.This topology implies that the acquisition of a ligulate character evolved twice in the lycopsids,once in the protolepidodendralean Leclercqia Banks et al.,and once in the heterosporous lycopsid clade. Phylogenetic positions of several lycopsid plants previously reported from the Mid-Upper Devonian of South China,which have uncertain ordinal affinities,were estimated by the cladistic analyses;cf. Longostachys Xue et Hao,Longostachys Zhu et al.,Monilistrobus Wang et Berry,and Yuguangia Hao et al.fall well within the Isoetales clade,as earliest members of this order,while Minostrobus Wang and Wuxia Berry et al.are nested within the basal part of the heterosporous lycopsids.Bayesian analyses are a very useful approach in systematic studies and can be applied in analyzing paleobotanical data sets as well.To investigate the phylogeny of early lycopsids,cladistic analyses using both parsimony and Bayesian approaches are presented,with a data matrix of 33 morphological characters across 25 taxa. The resulting parsimony and Bayesian trees showed overall similarities in tree topologies.In the Bayesian tree,the Protolepidodendrales and the heterosporous lycopsids are recognized as two monophyletic groups,and within the latter group,the Isoetales sensu lato forms a subclade.This topology implies that the acquisition of a ligulate character evolved twice in the lycopsids,once in the protolepidodendralean Leclercqia Banks et al.,and once in the heterosporous lycopsid clade. Phylogenetic positions of several lycopsid plants previously reported from the Mid-Upper Devonian of South China,which have uncertain ordinal affinities,were estimated by the cladistic analyses;cf. Longostachys Xue et Hao,Longostachys Zhu et al.,Monilistrobus Wang et Berry,and Yuguangia Hao et al.fall well within the Isoetales clade,as earliest members of this order,while Minostrobus Wang and Wuxia Berry et al.are nested within the basal part of the heterosporous lycopsids.Bayesian analyses are a very useful approach in systematic studies and can be applied in analyzing paleobotanical data sets as well.

关 键 词：Bayesian phylogenetics cladistic analysis LYCOPSID Protolepidodendrales DEVONIAN 

分 类 号：O212.8[理学—概率论与数理统计] S852.659.5[理学—数学]