Family CYSTISOMATIDAE Willemöes­Suhm, 1875

Diagnosis

Body very large, up to 150 mm, cuticle exceptionally transparent, pereonites and pleonites with short spines mid­dorsally and laterally. Head very large, as long as first 5­6 pereonites, rounded dorsally, flattened or slightly concave ventrally, with dentate border; ventral surface, anterior to mouthparts, with large anterior spine followed by glandular spine (A2), and sometimes row of up to 5 oral spines. Eyes comprise two oval areas dorsally and partly laterally. Pereonites 1 & 2 fused. Coxae fused with pereonites. Antennae 1 with small peduncular article and flagellum composed of one long, lanceolate proximal article, and one or two minute distal articles. Antennae 2 reduced to small spine on ventral surface. Mandibles without palp in both sexes, but with well­developed molar. Maxillae 1 with palp and well­developed outer lobe, inner lobe absent. Maxillae 2 with inner lobe reduced to small tubercle. Maxilliped well­developed, with long inner lobe, widening distally with concave distal margin. Gnathopods distinctly chelate, relatively small. Pereopods 3­7 consist of long narrow articles. Pereopod 5 the longest. Pereopod 7 of mature females prehensile, with dactylus closing against concave distal margin of propodus. Uropod 2 absent. Uropods 1 and 3 having endopod fused with peduncle. Telson very small, rounded. Gills on pereonites 4­6. Oostegites on pereonites 2­5, those on pereonites 4 and 5 rudimentary.

One genus: Cystisoma .