First record of a Facetotectan crustacean in plankton of Peter the Great Bay, Sea of Japan

Nauplii V of the rare crustacean Hansenocaris furcifera Itô, 1989, belonging to the infraclass Facetotecta were recorded in the plankton of Peter the Great Bay (Sea of Japan) for the first time. The larvae were probably transported in summer from the coastal waters off Japan. Scanning electron microscopic observations revealed previously unknown morphological characteristics of these larvae: three pairs of pore fields on the dorsal side of the carapace and the presence of processes covered with thickened setae and located at the base of mandibles.