Onuphis

Key to species of Onuphis present in European and nearby waters:

(Adapted from: Fauchald 1982b, Gil 2011)

1 All branchiae simple and strap-like........................................................................ 2

- Branchiae bifid or pectinate............................................................................. 4

2 Branchiae from chaetiger 1; pseudocompound hooks all tridentate; ventral cirri cirriform on the first 5–7 chaetigers; cirriform postchaetal lobes distinct on the first 10–13 chaetigers........................................................ 3

- Branchiae from chaetiger 5; pseudocompound hooks bi– and tridentate; ventral cirri cirriform on the first 4 chaetigers; cirriform postchaetal lobes distinct on the first 16–33 chaetigers in adults............................................................................................... Onuphis farensis sp. nov. (Gulf of Cádiz, SW Iberian Peninsula)

3 Maxillary formula: MI: 1+1, MII: 8-9+8, MIII: 9-10+0, MIV: 5-6+5, MV: 1+1.................. O. opalina (SE Iceland)

- Maxillary formula: MI: 1+1, MII: 6-8+8-9, MIII: 7-8+0, MIV: 7-9+9-11, MV: 1+1....... O. rullieriana (SW British Isles)

4 Branchiae pectinate, with up to 5–7 branchial filaments (first 15–20 chaetigers with simple branchiae)................. 5

- Branchiae bifid (first 20–25 chaetigers with simple branchiae); ventral cirri cirriform on the first 3–4 chaetigers; digitiform postchaetal lobes disappearing at chaetiger 7–8....................... O. falesia (Gulf of Follonica, Mediterranean Sea)

5 Tridentate pseudocompound hooks present on the first 3 chaetigers; branchiae pectinate, with up to 6–7 branchial filaments (first 18–20 chaetigers with simple branchiae); ventral cirri cirriform on the first 6 chaetigers; digitiform postchaetal lobes distinct in at least 60 chaetigers............................. O. eremita (European Atlantic coast and Mediterranean Sea)

- Bi – and tridentate pseudocompound hooks present on the first 2 chaetigers; branchiae pectinate, with up to 5–6 branchial filaments (first 15 chaetigers with simple branchiae); ventral cirri cirriform present from the first chaetiger, but total number unknown; digitiform postchaetal lobes present from the first chaetiger, but total number unknown...................................................................................... O. pancerii (Naples region, Mediterranean Sea)