A new superfamily and family of Hadziida (Amphipoda: Senticaudata), with a description of a new genus and new species from the Brazilian continental shelf Author Alves, Jessika Universidade Federal da Bahia (UFBA), Instituto de Biologia, LABIMAR-Laboratório de Invertebrados Marinhos-Crustacea, Cnidaria & Fauna associada, Ondina, Salvador, BA, CEP 40170 - 290, Brasil & jessika. aop @ gmail. com; https: // orcid. org / 0000 - 0003 - 0372 - 447 X Author Lowry, James K. Australian Museum Research Institute, 1 William Street, Sydney, New South Wales, 2010, Australia. Author Johnsson, Rodrigo Universidade Federal da Bahia (UFBA), Instituto de Biologia, LABIMAR-Laboratório de Invertebrados Marinhos-Crustacea, Cnidaria & Fauna associada, Ondina, Salvador, BA, CEP 40170 - 290, Brasil & r. johnsson @ gmail. com; https: // orcid. org / 0000 - 0003 - 1859 - 9421 text Zootaxa 2020 2020-05-21 4779 4 573 583 journal article 21920 10.11646/zootaxa.4779.4.8 e56bac47-d0c1-4850-9975-75f3c9c55588 1175-5326 3839550 AABD48D7-83B2-413A-80D8-60CACFF25311 Infraorder Hadziida Lowry & Myers, 2013 Included families. Calliopiidae Sars, 1895 ; Cheirocratidae Udekem d’Acoz, 2010 ; Crangoweckeliidae Lowry & Myers, 2012 ; Eriopisidae Lowry & Myers, 2013 ; Gammaroporeiidae Bousfield, 1979 ; Hadziidae S. Karaman, 1943 ; Hornelliidae Udekem d’Acoz, 2010 ; Maeridae Krapp-Schickel, 2008 ; Magnovidae fam. nov. ; Melitidae Bousfield, 1973 ; Megaluropidae Thomas & Barnard, 1986 ; Metacrangonyctidae Boutin & Messouli, 1988 ; Nuuanuidae Lowry & Myers, 2013 ; and Pontogeneiidae Stebbing, 1906 . Diagnostic description. Body laterally compressed, occasionally subcylindrical ( Magnovidae fam. nov. ). Antenna 1 accessory flagellum present.Antenna 2 peduncular article 1 not enlarged. Mandible molar strongly triturating of medium size or occasionally dominating mandible. Maxilliped inner plates well developed palp with 4 articles. Coxal gills on pereonite 2–6 or 2–7. Coxae 1–4 not ventrally acute. Coxae 1–3 well-developed, none hidden (except Megaluropidae ). Gnathopod 1 smaller than or similar in size to gnathopod 2. Gnathopod 2 dactylus well-developed, large. Pereopods 3–7 none prehensile. Pereopod 4 coxa without posteroventral lobe (except Gammaroporeiidae , Megaluropidae , Nuuanuidae ). Pereopods 5–7 without rows of facial or marginal setae. Pereopod 7 subequal or longer than pereopod 5 (occasionally much longer than pereopod 5, Megaluropidae ). Pereopod 7 similar in structure to pereopod 6. (except Megaluropidae ). Pleopods all well-developed. Epimera all well-developed. Urosomites 1–3 free. Uropods 1, 2 apices of rami with robust setae. Uropod 1 basofacial setae present or absent; without ventromedial spine. Uropod 3 biramous or occasionally uniramous. Telson laminar. Remarks. This set of characters separates the hadziidan amphipods from all other families.