First Record of the Rare Parasitic Isopod Elthusa splendida (Cymothoidae) from the Pacific Ocean, Based on a Specimen Found in a Museum Shark Collection

Abstract

An ovigerous female of the rare cymothoid isopod, Elthusa splendida (Sadowsky and Moreira, 1981) was discovered in a museum specimen of Japanese spurdog Squalus japonicus Ishikawa, 1908 collected from the East China Sea. This cymothoid species was previously known only from the type locality, off southern Brazil, the western South Atlantic. Therefore, the new record in the East China Sea represents the almost maximum distribution range extension on the earth (i.e., the antipodes). In addition, the present female is the largest specimen of this species on record (57.9 mm in total length). We described the East China Sea specimen along with verification of the presence of four pits on pereonite 1, an important diagnostic character of the species, using a 3D measurement system.