Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae) Author Ariyama, Hiroyuki Osaka Museum of Natural History, Nagai Park, Higashi-Sumiyoshi, Osaka 546 - 0034 Japan. Author Kodama, Masafumi International Coastal Research Center, Atmosphere and Ocean Research Institute, The University of Tokyo, 1 - 19 - 8 Akahama, Otsuchicho, Iwate 028 - 1102, Japan. mkodama @ aori. u-tokyo. ac. jp; https: // orcid. org / 0000 - 0002 - 0889 - 5625 Author Tomikawa, Ko Graduate School of Humanities and Social Sciences, Hiroshima University, 1 - 1 - 1 Kagamiyama, Higashihiroshima, Hiroshima 739 - 8524, Japan. tomikawa @ hiroshima-u. ac. jp; https: // orcid. org / 0000 - 0003 - 1521 - 9016 text Zootaxa 2020 2020-11-26 4885 3 336 352 journal article 9435 10.11646/zootaxa.4885.3.2 3ff96650-b8c7-40cb-a557-3f4e7a9d235d 1175-5326 4296670 45D0CE12-9E4D-4939-B3AB-A34717B3B104 Quadrimaera Krapp-Schickel & Ruffo, 2000 [Japanese name: Kaku-sunnariyokoebi-zoku] Synonym, diagnosis and included species. See Ariyama (2019) . However, on the mandibular palp in the diagnosis, “article 1 lacking distal tooth” is modified to “article 1 usually lacking distal tooth” (see Remarks of Quadrimaera angulata sp. nov. ). In addition, the following four species are added to the included species: Quadrimaera anhi Dang & Le, 2011 ; Q. miramirandella Alves, Neves & Johnsson, 2018 ; Q. vietnamica Dang & Le, 2011 ; and Q. yemanjae Alves, Neves & Johnsson, 2018 .