Echinorhynchus hexagrammi Baeva, 1965 (Acanthocephala: Echinorhynchidae) from marine fishes off Hokkaido, Japan, with morphological observations and new host records

Echinorhynchus hexagrammi Baeva, 1965 is redescribed on the basis of specimens collected from the saffron cod Eleginus gracilis (Tilesius) in Akkeshi Bay (western North Pacific) off Hokkaido, Japan. Eighteen museum specimens deposited as E. salmonis Müller, 1784 from Japanese coastal waters were also re-examined and re-identified as E. hexagrammi. Hexagrammos stelleri Tilesius, Hemitripterus villosus (Pallas), Podothecus sachi (Jordan & Snyder), Sebastes oblongus Günther and Verasper moseri Jordan & Gilbert are recognised as new hosts for E. hexagrammi. This acanthocephalan can be distinguished from three morphologically similar species, E. gadi Zoega in Müller, 1776, E. laurentianus Ronald, 1957 and E. salmonis, by the possession of the following characters: 12-16 (usually 14) rows of hook on the proboscis, a proboscis width of 170-240 μm in males and 195-270 μm in females, a hook root length of 35-45 μm in males and 40-50 μm in females, and linearly or almost linearly arranged cement glands in males. © 2011 Springer Science+Business Media B.V.