title: Phylogeny of freshwater parasitic copepods in the Ergasilidae (Copepoda: Poecilostomatoida) based on 18S and 28S rDNA sequences.
abstract: The phylogenetic relationships among the Ergasilidae genera are poorly understood. In this study, 14 species from four genera in the Ergasilidae including Sinergasilus, Ergasilus, Pseudergasilus, and Paraergasilus were collected in China, and their phylogenetic relationships were examined using neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian inference methods based on partial sequences of 18S and 28S ribosomal deoxyribonucleic acid, respectively. All the analyses suggest that the Sinergasilus and Paraergasilus are both monophyletic, but the Ergasilus is polyphyletic rather than monophyletic. Considering the relationships among the four genera, the phylogenetic analyses and subsequent hypothesis tests all suggest that Pseudergasilus clustered with some Ergasilus species may have a closer relationship with Sinergasilus rather than with Paraergasilus. It is proposed that the Sinergasilus and the Pseudergasilus species might have evolved from Ergasilus species.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, and Laboratory of Fish Diseases, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei Province, 430072, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Song
authors.forename: G T
authors.initials: GT
authors.lastname: Wang
authors.forename: W J
authors.initials: WJ
authors.lastname: Yao
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.forename: P
authors.initials: P
authors.lastname: Nie
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D033342:Copepoda / Q000235:genetics*; D004275:DNA, Ribosomal / Q000032:analysis; D019143:Evolution, Molecular; D005618:Fresh Water / Q000469:parasitology*; D016013:Likelihood Functions; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012337:RNA, Ribosomal, 18S / Q000235:genetics*; D012339:RNA, Ribosomal, 28S / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S