A Phylogeny and Classification of the Senticaudata subord. nov. (Crustacea: Amphipoda) Author Myers, A text Zootaxa 2013 3610 1 1 80 journal article 10.11646/zootaxa.3610.1.1 126b5f67-71bb-46e4-874c-7f8864ea8cd1 1175-5326 283309 AA71AC2D-C7BF-43AE-9E25-29A5EC843B89 Pachyschesidae Kamaltynov, 1999 Type genus. Pachyschesis Bazikalova, 1945 . Diagnostic description. Body laterally compressed. Eyes well developed, poorly developed or absent, if present then round, ovoid, reniform, ventrally tapered or subrectangular. Antennae 1–2 calceoli absent. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2; article 2 longer than article 3; article 3 shorter than article 1; peduncular articles 1–2 not geniculate; accessory flagellum short or minute. Antenna 2 peduncular article 1 enlarged, bulbous . Mandible palp symmetrical. Maxilla 1 basal endite apically setose; palps symmetrical. Maxilla 2 basal endite without oblique setal row. Labium inner lobes 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); similar in size to gnathopod 2; propodus palm without robust setae along palmar margin. Gnathopod 2 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 without posteroventral lobe . Pereopod 5 subequal in length to pereopod 6 ; coxa with large or with small anteroventral lobe. Pereopod 7 subequal in length to pereopod 5. Pleonites 1–3 without dorsal carinae. Urosomites 1–3 free; with slender or robust dorsal setae . Urosomite 1 without large distoventral robust seta. Urosomite 2 without dorsal setae. Uropod 1 without basofacial robust setae. Uropod 3 not sexually dimorphic; biramous, with plumose setae; endopod shorter than exopod . Telson deeply cleft ; dorsal or lateral robust setae absent; apical robust setae absent. Habitat. Freshwater, epigean. Included genera. Pachyschesis Bazikalova, 1945 . Distribution. Lake Baikal.