Wikipedia
Epicaridea is a former suborder of isopods, now treated as part of the suborder Cymothoida. They are ectoparasites that inhabit other crustaceans, namely ostracods, copepods, barnacles and malacostracans. The suborder is found globally. About 704 species have been recorded. Epicaridea are generally less well researched than other isopods.
There is a high degree of sexual dimorphism within the order. The female is commonly very asymmetrical, often losing segmentation. Two pairs of rudimentary antennae are carried on the head. Mouthparts show little development, with only mandibles and maxilliepeds present, sometimes with a second pair of rudimentary maxillae. Males are of smaller size than females and of different appearance. Development is through regressive metamorphosis, undergoing two or three larval stages.