(= Family Lysianassidae Dana, 1849 sensu lato)
Peduncle of ANT I short, stout, ART 1 often barrel-like, ART 2 and 3 usually much shorter than 1. Accessory flagellum usually present, more than 3-articulated, rarely absent. Pereon lacking processes, urosomal segment I often with proximal dorsal depression, distal dorsal process. Body usually compact (especially in benthic and necto-benthic forms), chitin smooth, often dense. Mouth parts very variable, often with more or less reduced mandibular molar and variable position of mandibular palp, some lobes or palps of maxillae and MXP also may be reduced. P I and II (gnathopods) usually smaller than others, P I simple or prehensile, P II specifically elongate, slender, minutely chelate or subchelate (rarely simple), ART 3 elongate, ART 5 and 6 densely setose, dactyl minute. Coxae usually long, coxae I to III occasionally reduced in size and/or hidden by following coxae. CX IV with indentation on posterior margin (rare in other species), anterior margin of CX V occupying this indentation, CX V often bilobate. Rami of UR III lanceolate, exopodite often 2-articulated, endopodite may be reduced in size. Telson cleft, emarginate or entire, long or short, rarely absent. About 170 genera, mainly benthic. Ten genera in the South Atlantic plankton. "The Lysianassidae have been and are being divided into groups by various taxonomists but no comprehensive synoptic classification has appeared as yet" (Barnard and Karaman, 1991, P. 421).
Genera treated:
Genus Cyphocaris Boeck, 1871
Genus Danaella Stephensen, 1925
Genus Eurythenes Smith in Scudder, 1882
Genus Hirondellea* (Hirondellea brevicaudata Chevreux, 1910)
Genus Metacyphocaris Tattersall, 1906
Group Orchomene (genera Orchomene, Orchomenella, Orchomenopsis, Allogaussia and Tryphosa)
Genus Paracyphocaris Chevreux, 1905
Genus Scopelocheiropsis Schellenberg, 1926
Genus Thoriella Stephensen, 1915