New host and ocean records and remarks on the morphology and behavior of Jusheyus shogunus (Copepoda : Siphonostomatoida: Eudactylinidae)

Jusheyus shogunus Deets and Benz, 1987 (Copepoda: Eudactylinidae) is report ed from wreckfish, Polyprion americanus (Schneider, 1801) collected from wi dely separated locations in the north Atlantic. This represents a new host record and new ocean report for this parasite. Examination of male and fema le copepods allowed some confusion regarding the morphology of J. shogunus re, be eliminated. Jusheyus shogunus possesses a cephalothorax rather than a cephalosome and its dorsal styliform processes are connected by an intern al bridging sclerite and an external dorsal plate that is hinged to its cep halothorax. Each process also articulates with its own internal ventral scl erite. A series of muscles services these structures, and comparisons of th e dorsal styliform processes of J. shogunus with the dorsal stylers of Kroy eria spp, revealed some morphological similarities. Adult female J. shogunu s in the study collection Varied in size from 2.16 to 4.97 mm total length, and smaller and larger specimens presented somewhat different body forms. Most egg sacs contained multiseriately arranged eggs; however, several spec imens possessed a sac whose distal portion contained uniseriately arranged eggs and whose proximal portion contained 2 rows of eggs. Jusheyus shogunus attaches to the gill filament lamellae of its hosts using its second anten nae and maxillipeds. The dorsal styliform processes can be erected by eithe r directly raising them or by flexing the cephalothorax at its junction wit h the first free thoracic segment. In either case the tips of the processes can engage 1 to several lamellae on the adjacent gill filament to help sec ure the parasite.