Ohtsuka Susumu, Nishikawa Jun, Boxshall Geoffrey A
Takehara Station, Seotuchi Field Science Center, Graduate School of Biosphere Science, Hiroshima University, 5-8-1 Minato-machi, Takehara, Hiroshima 725-0024, Japan.
Department of Marine Biology, School of Marine Science and Technology, Tokai University, Orido, Shimizu, Shizuoka 424-8610, Japan.
Parasite. 2018;25:58. doi: 10.1051/parasite/2018057. Epub 2018 Nov 26.
Peniculus hokutoae n. sp. is described on the basis of an ovigerous adult female parasitizing the caudal fin of the myctophid fish Symbolophorus evermanni (Gilbert, 1905), collected from Suruga Bay, Japan. This is the first record of parasitism by this genus on mesopelagic myctophid fish. The new species is easily distinguished from other congeners in: (1) the presence of a conical process anterior to the rostrum; (2) the secondary elongation of the first pedigerous somite; (3) the incorporation of the third and fourth pedigerous somites into the trunk; (4) the unilobate maxillule bearing two unequal apical setae; (5) the lack of any processes on the first segment of the maxilla. Four morphological patterns of the cephalothorax, neck and anterior parts of the trunk can be found in the genus. We infer that initial colonization of a mesopelagic myctophid fish as host is likely to have occurred when the diurnally-migrating myctophid host was feeding in near-surface waters at night and was exposed to infective stages of Peniculus.
北太平洋彭氏鱼虱新种（Peniculus hokutoae n. sp.）是根据一只寄生在日本骏河湾采集的埃氏烛光鱼（Symbolophorus evermanni，Gilbert，1905）尾鳍上的抱卵成年雌体描述的。这是该属寄生在中层烛光鱼科鱼类上的首次记录。新种与其他同属物种易于区分之处在于：（1）在吻前方有一个圆锥形突起；（2）第一带卵节次生延长；（3）第三和第四带卵节并入躯干部；（4）小颚单叶，具两根不等长的顶端刚毛；（5）上颚第一节无任何突起。该属可发现四种头胸部、颈部和躯干部前部的形态模式。我们推断，当中层烛光鱼科鱼类宿主在夜间到近海水域摄食并接触到彭氏鱼虱的感染阶段时，可能就开始寄生在这种宿主上了。
