A redescription of Hemilaophonte janinae Jakubisiak (Copepoda, Harpacticoida), a laophontid living in the gill chambers of the common spider crab.

Hemilaophonte janinae JAKUBISIAK, living in the gill chambers of the common spider crab Maja squinado (HERBST), is redescribed in detail. Specimens of this harpacticoid were found on crabs collected along the Atlantic coasts of France and the Spanish Sahara. H. clysmae POR and MARcus, the second species assigned to the genus, is allocated to the closely related genus Coullia HAMOND. Whereas the common spider crab shows a wide distribution throughout the Mediterranean, H. janinae has only been found on crabs from the Atlantic Ocean. Spider crabs from the Mediterranean Sea mainly host laophontids of the genus Paralaophonte LANG.