Key to the genera of the family OXYCEPHALIDAE

1. Body extremely slender, with long, needle-shaped rostrum. Pereopod 7 reduced to basis (sometimes with one or two additional articles)......................................................................... Rhabdosoma White, 1847

- Body only moderately slender, rostrum produced into sharp or blunt point, never needle-shaped. Pereopod 7 with all articles present or if reduced, body is robust....................................................................... 2

2. Rostrum with broad lateral flanges................................................ Calamorhynchus Streets, 1878

- Rostrum without lateral flanges.......................................................................... 3

3. Double urosomite length more than 3 x width. Uropod 1 with very short exopod................. Leptocotis Streets, 1877

- Double urosomite length less than 3 x width. Uropods 1–3 with well-developed exopoda and endopoda................. 4

4. Rostrum rounded or only slightly pointed. Pereopods 5 & 6 with basis not much wider than following articles........................................................................................ Glossocephalus Bovallius, 1887

- Rostrum pointed. Pereopods 5 & 6 with basis considerably wider than following articles............................. 5

5. Pereopod 6; basis with postero-distal corner produced into distinct, almost up-turned, triangular process. Pereopod 7 with reduced number of articles........................................................ Tullbergella Bovallius, 1887

- Pereopod 6; basis with rounded postero-distal corner, not produced. Pereopod 7 with all articles present................. 6

6. Uropods 2 & 3; endopod fused with peduncle. Gnathopod 1 chelate.................. Oxycephalus Milne-Edwards, 1830

- Uropods 2 & 3; endopod articulated with peduncle. Gnathopod 1 sub-chelate...................................... 7

7 Head barrel-shaped. Coxae free, without processes........................................ Streetsia Stebbing, 1888

- Head globular. Coxae fused with pereonites. Pereonite 5 (fused coxa) often produced into backward-pointed process................................................................................... Cranocephalus Bovallius, 1890