EPICARIDEA 107 



Suborder Epicaridea Latreille, 1831 



DIAGNOSIS Predominantly ectoparasites of marine crustaceans, feeding on 

 blood. Eyes sessile, usually present in 6, often reduced or lost in 9. Anten- 

 nae and antennules reduced; mouthparts reduced, forming a suctorial cone 

 containing pair of piercing stylets formed from modified mandibles. Maxillae 

 1 and 2 reduced or lost. All mouthparts may be lost, and replaced by pro- 

 boscis. 6 small and isopodlike. 9 undergo considerable distortion or reduc- 

 tion, often to unsegmented sacs of eggs in some forms. Ostegites usually re- 

 tained. Two larval mancalike stages, epicaridium and cryptoniscium (Figure 

 49), characteristic of entire suborder. 



REMARKS The epicarideans are ectoparasites of other crustaceans, with the 

 juveniles often using copepods as intermediate hosts. Sexual dimorphism is 

 marked, the males being symmetrical with unambiguous segmentation, and 

 considerably smaller than the often highly distorted females. In these, body 

 segmentation is often obscured, with body segments often expanded on one 

 side and reduced and compressed on the other. The marsupium of the 

 ovigerous female, except in the Crvtoniscidae and Entoniscidae, is made up ^ 

 of broadly lamellar oostegites, is relatively enormous and often obscures the 

 rest of the body structure. 



Crustacean hosts of the epicarideans are found in four classes: Ostracoda, 

 Copepoda, Cirripedia, and Malacostraca, and in nine orders of the Mal- 

 acostraca: Leptostraca, Stomatopoda, Mysidacea, Cumacea, Tanaidacea, 

 Isopoda, Amphipoda, Euphausiacea, and Decapoda. The Epicaridea have 

 been divided into two superfamilies, the Bopyroidea, containing families 

 Bopyridae, Dajidae, and Entoniscidae, and the Cryptoniscoidea, containing 

 the Crvtoniscidae. 



In tne Bopyridae (Figure 50), the often asymmetrical adult female shows 

 some segmentation. Seven pereopods may be present only on one side, their 

 number being variable on the other. This is largest of the epicaridean fam- 

 ilies, containing over 400 species (Markham, 1974). Ten subfamilies have 

 been recognized: the monotypic Entophilinae parasitizes galatheid crabs; six 

 subfamilies, the Argeiinae, Bopyrinae, Bopyrophryxinae, loninae, Pseu- 

 dioninae, and Orbioninae are all branchial parasites of decapod crustaceans; 

 two subfamilies are abdominal parasites, the Phyllodurinae on callianassid 

 mud-shrimps, and the Athelginae on hermit crabs; the Hemiarthrinae are 

 known from the dorsal and ventral abdominal surfaces, and from the 

 branchial chamber of caridean shrimps. 



The Dajidae are ectoparasites pelagic mysidaceans, euphausiaceans, and 

 decapod caridean shrimps. Adult females are often found unattached in 

 plankton and pelagic samples. When attached, dajids are found on the 



