Key to species of the genus Oxycephalus Milne-Edwards, 1830 1. Pleonite 1, or pleonites 1–3, with sharp, medial tooth on ventral margin, in addition to tooth on postero-distal corner....... 2 - Pleonites without sharp medial projection on ventral margin.................................................... 3 2. Pleonites 1–3 with medial tooth on ventral margin. Gnathopods 1 & 2; carpus with antero-distal corner produced into sharp point, above propodus (not always apparent in immature specimens)......................... O. clausi Bovallius, 1887 - Only pleonite 1 with medial tooth on ventral margin (usually only in juvenile specimens less than 10 mm). Gnathopods 1 & 2; carpus without antero-distal corner produced...................................... O. piscator Milne-Edwards, 1830 3. Cutting edges of carpus and propodus of G1 & 2 with row of closely packed, relatively long, sharp teeth. Pereopod 7 of females with stylifrom propodus, slightly longer than ischium to carpus combined.............. O. latirostris Claus, 1879 - Cutting edges of carpus and propodus of G1 & 2 with few teeth, not in distinct row. Pereopod 7 of both sexes with normal propodus, only slightly longer, or shorter than carpus............................... O. piscator Milne-Edwards, 1830

Published as part of Zeidler, Wolfgang, 2016, A review of the families and genera of the superfamily PLATYSCELOIDEA Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), together with keys to the families, genera and species, pp. 1-136 in Zootaxa 4192 (1) on page 76, DOI: 10.11646/zootaxa.4192.1.1, http://zenodo.org/record/166420