Type genus. Pseudocrangonyx Akatsuka & Komai, 1922.
Diagnostic description. Body subcylindrical. Eyes well developed or 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 minute. Antennae 1–2 calceoli absent. Antenna 2 peduncular article 1 enlarged, bulbous. Mandible molar triturative; palp present, symmetrical. Maxilla 1 basal endite apically setose; palps symmetrical. Maxilla 2 basal endite with oblique setal row. Labium inner lobes vestigial or absent. Coxal gills on pereopods 2–7, stalked with proximal suture; sternal gills present, simple; sternal blisters present or absent; oostegites fringing setae simple. Gnathopod 1 subchelate; dissimilar in males and females (sexually dimorphic); similar in size to, or larger (or stouter) than gnathopod 2; propodus palm with peglike robust setae along palmar margin. Gnathopod 2 subchelate; dissimilar 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 without posteroventral lobe. Pereopod 5 shorter than pereopod 6; coxa with small anteroventral lobe. Pereopod 7 longer than 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 with 1 or 2 basofacial robust setae. Uropod 3 sexually dimorphic; uniramous, without plumose setae. Telson notched, emarginate or entire; dorsal or lateral robust setae absent; apical robust setae present.
Habitat. Freshwater, hypogean.
Included genera. Procrangonyx Schellenberg, 1934; Pseudocrangonyx Akatsuka & Komai, 1922. Distribution. North-eastern China, eastern Siberia (including the Kamchatka Peninsula), Korea and the Japanese Islands.