Crangonyctidae Bousfield, 1973

Type genus. Crangonyx Bate, 1859 .

Diagnostic description. Body laterally compressed or subcylindrical. Eyes well developed or absent, if present then round, ovoid or subrectangular. Antennae 1–2 calceoli crangonyctoid (type 9). Antenna 1 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 minute. Antenna 2 peduncular article 1 enlarged, bulbous. Mandible molar triturative; palp symmetrical. Maxilla 1 basal endite setose along medial margin or apically setose; palps symmetrical. Maxilla 2 basal endite with oblique setal row. Labium inner lobes present. Coxal gills number and sequence [not known], stalked (with proximal restriction or complete suture); sternal gills present, simple; 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 with row or rows of simple or bifid 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 with well developed posteroventral lobe or without posteroventral lobe. Pereopod 5 shorter than, subequal in length to, or longer than pereopod 6; coxa with large anteroventral lobe or with small anteroventral lobe. Pereopod 7 shorter than, subequal in length to, or longer than pereopod 5. Pleonites 1–3 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 with 1 or 2 basofacial robust setae or without basofacial robust setae. Uropod 3 not sexually dimorphic; biramous, uniramous or rami absent, without plumose setae; endopod minute or shorter than exopod. Telson moderately cleft, notched, emarginate or entire; dorsal or lateral robust setae absent; apical robust setae present.

Habitat. Freshwater, hypogean and epigean.

Included genera. Bactrurus Hay, 1902; Crangonyx Bate, 1859; Lyurella Derzhavin, 1939; Pachypodacrangonyx Boutin & Coineau, 1987; Stygobromus Cope, 1872; Stygonyx Bousfield & Holsinger, 1989; Synurella Wrzesniowski, 1877 .

Distribution. Holarctic.