New Mesopsyllus species from the Bohai Sea, China, re-evaluation of the validity of Vibriopsyllus Kornev & Chertoprud, 2008 and proposal of Sympodella gen. n. (Copepoda, Harpacticoida, Canthocamptidae)

Abstract. Two new species of the genus Mesopsyllus Por, 1960 (Canthocamptidae) are described from the Bohai Sea, eastern China. Mesopsyllus dimorphus sp. n. and M. spiniferus sp. n. differ from their congeners by the presence of two instead of three outer spines on P2–P3 exp-3. They can be differentiated from each other by (1) number of inner setae on P3–P4 enp-2; (2) anterior margin of antennulary segment 7 of male; (3) ornamentation of male abdomen; (4) sexual dimorphism on P2 endopod and P3–P4 exp-3; and (5) differences in length of setae on male P5. Some observations in the original description of M. atargatis Por, 1960 are reinterpreted and the type material of M. secundus (Wells, 1965) is re-examined. Comparison between the type species of Vibriopsyllus Kornev & Chertoprud, 2008 and the four known species of Mesopsyllus shows the former as a junior subjective synonym of the latter. Consequently, Vibriopsyllus curviseta Kornev & Chertoprud, 2008 is formally transferred to Mesopsyllus as M. curvisetus (Kornev & Chertoprud, 2008), comb. n. A key to species and an updated generic diagnosis of Mesopsyllus are presented. The taxonomic status of the genus Carolinicola Huys & Thistle, 1989 is re-evaluated. The characters of its type species, C. trisetosa (Coull, 1973), indicate that the latter (and – by inference – the genus Carolinicola) should remain in the Danielsseniinae. Carolinicola galapagoensis Mielke, 1997 is fixed as the type species of a new genus Sympodella gen. n. and placed in the Hemimesochrinae (Canthocamptidae) as the putative sistertaxon of Pusillargillus Huys & Thistle, 1989. The relationships and potential synonymy of the genera Pyrocletodes Coull, 1973, Perucamptus Huys & Thistle, 1989 and Isthmiocaris George & Schminke, 2003 are briefly discussed.