2020 Volume 29 Pages 45-48
The ectoparasitic isopod Holophryxus fusiformis Shiino, 1937 was found attached to the dorsal part of a male shrimp Sergia laminata (Burkenroad, 1940) carapace in Suruga Bay of Japan. We report that S. laminata is a new host decapod for this rare parasite. Observation of a live specimen indicated that H. fusiformis was similar in color to that of the host shrimp, which may be a form of camouflage from predators in the bathypelagic layer. Females of this parasitic isopod have been recorded from three species of pelagic shrimps viz., S. laminata, Lucensosergia lucens (Hansen, 1922) and Prehensilosergia prehensilis (Spence Bate, 1881) and are newly revealed to change the body colors depending on those of the hosts.