2010年2月14日 星期日

使用四個基因序列重建脂鯉目的親緣關係不支持多數大屬(如Astyana, Hyphessobrycon, Bryconamericus, Hemigrammus)的單系性, 而銀大眼脂鯉亞科(銀銅燈)應僅限用於該屬

文獻來源: Javonillo R, Malabarba LR, Weitzman SH, Burns JR. 2010. Relationships among major lineages of characid fishes (Teleostei: Ostariophysi: Characiformes), based on molecular sequence data, Molecular Phylogenetics and Evolution, 54(2): 498-511.

Abstract

The family Characidae is a group of freshwater bony fishes that exhibits high species-level diversity and whose members inhabit parts of Texas, Mexico, and Central and South America. Thus far, morphological data have been of limited use in discerning relationships among subfamilies and incertae sedis genera of the family Characidae. In this study, DNA sequence data from GenBank were combined with new sequences for analyses under Bayesian and parsimony schemes. Sequences fell into four gene partitions, with three genes in the mitochondrial subset (12S, 16S, COI genes) and one gene in the nuclear subset (RAG2 gene). Inferred Bayesian and parsimony-based phylogenies reject the monophyly of certain groups (e.g., Astyanax, Hyphessobrycon, and Bryconamericus), do not reject the monophyly of others (e.g., Cheirodontinae and 'clade A' of previous authors), and present new sister-group hypotheses (e.g., Brittanichthys sister to Paracheirodon). Sister to clade A is a lineage referred to herein as 'clade B' which includes Exodon and exemplars from Cheirodontinae (the most basal lineage within clade B), Aphyocharacinae, Tetragonopterinae, and Characinae (excluding Gnathocharax). 'Clade C' is sister to A + B and contains representatives of large incertae sedis genera (e.g., Hyphessobrycon, Hemigrammus), as well as members of Stethaprioninae. Unless certain other subfamilial names are to be disregarded, the use of Tetragonopterinae should continue to be restricted to species of Tetragonopterus because other genera previously referred to this subfamily grouped in clades A or C, quite distant from Tetragonopterus.