Haplostomides hawaiiensis,new species (Copepods: Cyclopoida: Ascidicolidae), associated with the ascidian Polyclinum constellatum at Honolulu,Hawaii

An ascidicolid copepod, Haplostomides hawaiiensis, is described on the basis of females obtained from the compound ascidian Polyclinum constellatum collected in Keehi Lagoon, Honolulu, Hawaii. The features that separate H. hawaiiensis from other species of the genus include an elongate body with dorsal curvature and indistinct tagmosis, and a combination of characters of cephalic appendages (antenna with 2 spines, mandible with 3 setae, maxillule with 7 setae and maxilla with 2 setae) and thoracic appendages (legs 1–4 with 1 seta on protopod and 2 spines and 1 seta on exopod). Haplostomides hawaiiensis appears to be most closely related to H. hibernicus (T. & A. Scott, 1895) which occurs in compound ascidians from European seas. This is the first copepod associate of an ascidian to be reported from Hawaii.