鳋科一新种及其扫描电镜观察(甲壳亚门: 桡足亚纲)

记述了寄生在zhao属鱼类上的寄生桡足类鳋科1新种——匙刺鳋Ergasilus cochlearius sp.l nov., 其第一至第四对足内肢末节的刺均为匙形, 第一胸节与头部等宽, 以游泳足的刚毛式和口器等, 而与E. spatulus Cressey相区别。模式标本存第一作者单位。图16参2

Phylogeny of freshwater parasitic copepods in the Ergasilidae (Copepoda : Poecilostomatoida) based on 18S and 28S rDNA sequences

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.