Calliopiidae Sars, 1895 b

Type genus. Calliopius Lilljeborg, 1865 .

Diagnostic description. Body laterally compressed. Eyes well developed, round, ovoid, reniform, subrectangular or occupying most of lateral surface of head. Antennae 1–2 calceoli pontogeneiid (type 4). Antenna 1 shorter than, subequal in length to, or longer than antenna 2; peduncular article 1 subequal to, or longer than article 2; article 2 longer than article 3; article 3 shorter than article 1; peduncular articles 1–2 not geniculate; accessory flagellum present or absent; if present minute or scale-like. Antenna 2 peduncular article 1 not enlarged. Mandible molar triturative; palp symmetrical. Maxilla 1 basal endite setose along medial margin or apically setose; palps symmetrical. Maxilla 2 basal endite with or without oblique setal row. Labium inner lobes present, vestigial or absent. Coxal gills on pereopods 2–6, not stalked; sternal gills absent; sternal blisters absent; oostegites fringing setae simple. Gnathopod 1 simple or subchelate; similar in males and females (not sexually dimorphic); smaller (or weaker) than or similar in size to gnathopod 2; propodus palm with row or rows of simple or bifid robust setae or with one to several simple or bifid robust setae, or without robust setae along palmar margin. Gnathopod 2 simple or subchelate; similar in males and females (not sexually dimorphic); carpus not produced along posterior margin of propodus, projecting between merus and propodus. Pereopods 3–4 not sexually dimorphic. Pereopod 4 with well developed or without posteroventral lobe. Pereopod 5 shorter than or subequal in length to pereopod 6; coxa equilobate or with posteroventral lobe or with posterodorsal lobe or with large anteroventral lobe. Pereopod 7 subequal in length to, or longer than pereopod 5. Pleonites 1–3, pleonites 1–2 each with carina or each with dorsal carina or carinae or without dorsal carinae. Urosomites 1–3 free; without slender or robust dorsal setae. Urosomite 1 with or without large distoventral robust seta. Urosomite 2 without dorsal setae. Uropod 1 without basofacial robust setae. Uropod 3 not sexually dimorphic; biramous, with or without plumose setae; endopod subequal in length to, or longer than exopod. Telson notched, emarginate or entire; dorsal or lateral robust setae absent; apical robust setae absent.

Habitat. Marine, freshwater, epigean.

Included genera. Amphithopsis Boeck, 1861; Apherusa Walker, 1891; Bouvierella Chevreux, 1900 q; Calliopiella Schellenberg, 1925; Calliopiurus Bushueva, 1986; Calliopius Lilljeborg, 1865; Cleippides Boeck, 1871; Domicola Pretus & Abello 1993; Frigora Ren, 1991; Halirages Boeck, 1871; Haliragoides Sars, 1895 b; Harpinioides Stebbing, 1888; Laothoes Boeck, 1871; Leptamphopus Sars, 1895 b; Lopyastis Thurston, 1974; Lutriwita Lowry & Myers, 2012; Manerogeneia Barnard & Karaman, 1987; Membrilopus Barnard & Karaman, 1987; Metaleptamphopus Chevreux, 1911 a; Oligochinus J.L. Barnard, 1969 b; Oradarea Walker, 1903; Paracalliopiella Tzvetkova & Kudrjaschov, 1975; Pontogeneoides Nicholls,1938; Rozinante Stebbing, 1894; Stenopleura Stebbing, 1888; Stenopleuroides Birstein & Vinogradov, 1964; Tylosapis Thurston, 1974; Weyprechtia Stuxberg, 1880 .

Distribution. Cosmopolitan.