Marine Isopods of the Caribbean 



Phylum Arthropoda 

 Superclass Crustacea Pennant, 1777 

 Class Malacostraca Latreille, 1806 

 Subclass Eumalacostraca Grobben, 1892 

 Superorder Peracarida Caiman, 1904 

 Order Isopoda Latreille, 1817 



DIAGNOSIS Body usually dorsoventrally depressed, occasionally sub- 

 cylindrical, rarely bilaterally compressed. Carapace lacking. Antennules and 

 antennae uniramous (scale on antenna in some asellotes may represent rudi- 

 mentary second ramus). Eyes sessile (although situated on nonmobile stalks 

 in some asellotes). Mouthparts consisting of one pair of mandibles, two pairs 

 of maxillae, one pair of maxillipeds; latter appendages of first thoracic seg- 

 ment fused with cephalon. Mandible usually with palp consisting of one to 

 three articles; incisor, lacinia mobilis, and molar usually present; lacinia mo- 

 bilis often differing on left and right sides, sometimes absent from right man- 

 dible; molar variable. Maxilliped usually consisting of palp of no more than 

 five articles, lamellar endite often with coupling hooks, lamellar epipod. Per- 

 eonites usually separate, although pereonite 1 sometimes fused with 

 cephalon. Coxae of pereopods variously fused with, and forming expanded 

 lateral processes of, pereonites. Pereopod 1 forming additional mouthpart 

 (pylopod) only in Gnathiidea. Pereopods generally similar, ambulatory; 

 pereopods 1-3 secondarily variously modified and becoming subchelate or 

 prehensile; pereopods 4-7 occasionally modified, becoming natatory or pre- 

 hensile. Pereopod 7 occasionally not developed (neotenous condition). 

 Broodpouch or marsupium formed by varying number of oostegites attached 

 ventrally and medially to coxae of pereopods; eggs held in anterior or pos- 

 terior pockets or internal pouches in gnathiids and some sphaeromatids. 

 Pleon consisting of six pleonites, free or variously fused, plus telson; if one or 

 more pleonites fused with telson, resulting structure referred to as pleotelson. 



13 



