Maeridae Krapp-Schickel, 2008 a (Lowry & Hughes, 2009)

Type genus. Maera Leach, 1814 .

Diagnostic description. Body laterally compressed or subcylindrical. Eyes well developed or absent, if present then round, ovoid, reniform, lageniform or subrectangular. Antennae 1–2 calceoli absent. Antenna 1 subequal in length to, or longer than antenna 2; peduncular article 1 shorter than, 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 long, short or minute. Antenna 2 peduncular article 1 not enlarged. Mandible molar triturative; palp symmetrical or absent. 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 subchelate; similar in males and females (not sexually dimorphic); smaller (or weaker) than or similar in size to gnathopod 2; propodus palm without robust setae along palmar margin. Gnathopod 2 Gnathopod 1 subchelate; dis similar in males and females (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 posteroventral lobe or with small posteroventral lobe or without posteroventral lobe. Pereopod 5 shorter than or subequal in length to pereopod 6; coxa with posteroventral lobe or with large anteroventral lobe or with small anteroventral lobe or without lobes. Pereopod 7 subequal in length to, or longer than pereopod 5. Pleonites 1–3 without dorsal carinae. Urosomites 1–3 free; with or without slender or robust dorsal setae. Urosomite 1 without large distoventral robust seta. Urosomite 2 with pair of dorsal concavities each with 1–3 small setae or without dorsal setae. Uropod 1 with 1 or 2 basofacial robust setae or without basofacial robust setae. Uropod 3 sexually dimorphic or not; biramous, without plumose setae; endopod shorter than or subequal to exopod. Telson deeply cleft to entire; dorsal or lateral robust setae present or absent; apical robust setae present or absent.

Included genera. Anamaera Thomas & Barnard, 1985 a; Anelasmopus Oliveira, 1953; Animoceradocus G. Karaman, 1984d; Austromaera Lowry & Springthorpe, 2005; Bathyceradocus Pirlot, 1934; Beaudettia J.L. Barnard, 1965; Ceradocoides Nicholls, 1938; Ceradocopsis Schellenberg, 1926; Ceradocus Costa, 1853; Ceradomaera Ledoyer, 1973; Clessidra Krapp-Schickel & Vader, 2009; Coxomaerella G. Karaman, 1981c; Dumosus Thomas & Barnard, 1985 b; Elasmopoides Stebbing, 1908; Elasmopus Costa, 1853; Glossomaera Krapp- Schickel, 2009; Hamimaera Krapp-Schickel, 2008 a; Hoho Lowry & Fenwick, 1983; Ifalukia J.L. Barnard, 1972 a; Jerbarnia Croker, 1971; Linguimaera Pirlot, 1936; Lupimaera Barnard & Karaman, 1982; Maera Leach, 1814; Maeracoota Myers, 1997; Maerella Chevreux, 1911 b; Maeropsis Chevreux, 1919; Mallacoota J.L. Barnard, 1972 a; Megaceradocus Mukai, 1979; Metaceradocoides Birstein & Vinogradov, 1960; Meximaera J.L. Barnard, 1969 c; Othomaera Krapp-Schickel, 2000; Paraceradocus Stebbing, 1899 b; Parapherusa Haswell, 1879 b; Parelasmopus Stebbing, 1888; Pseudelasmopus Ledoyer, 1978; Quadrimaera Krapp-Schickel & Ruffo, 2000; Quadrivisio Stebbing, 1907; Ruffomaera Krapp-Schickel, 2008 b; Saurodocus Yerman & Krapp-Schickel, 2008; Spathiopus Thomas & Barnard, 1985 a; Thalassostygius Vonk, 1990; Wimvadocus Krapp-Schickel & Jarrett, 2000; Zhadia, Lowry & Fenwick, 1983; Zygomaera Krapp-Schickel, 2000 .

Habitat. Marine, epigean.

Remarks. Maeridae is very similar to Hadziidae . They are separated by the coxal gills which are stalked in hadziids. Maeridae is also very similar to Melitidae . They are separated by the head shape of lateral cephalic lobe; gnathopod 1 with robust setae along palm; the form of the first and second uropods and the inner ramus of uropod 3.

Distribution. Cosmopolitan.