Latreille, 1831
Epicaridea are Isopoda that are endoparasitic on exclusively Crustacea —Êfeeding on blood. The effected crustaceans are pelagic or benthic, and involve Ostracoda, Copepoda, Cirripedia, Leptocostraca, Stomatopoda, Mysidacea, Cumacea, Tanaidacea, Isopoda, Amphipoda, Euphausiacea, and Decapoda.
Epicaridea are often showing extreme specialisation and loss of body forms in the adult. Typically there are three consecutive juvenile stages before the final host is infected. The hatching stage is the epicaridium, which resembles juvenile species of the Family Sphaeromatidae (Isopoda), with well-developed cephalic, pereional and pleonal appendages. It has styliform, suctorial mouthparts and six pairs of clawed pereiopods enabling it to attach to the primary host, which is usually a species of the subclass copepoda. On the primary host it undergoes a number of ecdyses as the microniscus before eventually swimming free as the cryptoniscus, which resembles species of the Family Cirolanidae (Isopoda), and which infects the final host. In general in epicaridians males retain the cryptoniscus form and are to be found attached to the posterior ventral surface of large and highly modified females.
There are four families of Epicaridea represented in the North Sea; each is host-specific. The species are not keyed out here.
¥ Family Bopyridae: in gill chambers or attached to the pleon of Decapoda.
¥ Family Etoniscidae: in the visceral cavity of Decapoda.
¥ Family Dajidae: in the body or brood chambers of Mysidacea and Euphausiacea.
¥ Family Cryptoniscidae: in Cirripedia, Isopoda and Ostracoda.
[Naylor, 1972]