Aphanodomus terebellae ( Levinsen, 1878 )

Boxshall, Geoff A., O’Reilly, Myles, Sikorski, Andrey & Summerfield, Rebecca, 2019, Mesoparasitic copepods (Copepoda: Cyclopoida) associated with polychaete worms in European seas, Zootaxa 4579 (1), pp. 1-69 : 65

Aphanodomus terebellae ( Levinsen, 1878)

Syn: Crypsidomus terebellae Levinsen, 1878

Scandinavian material examined: 1 ovigerous ♀ from Leaena abranchiata , ECASA, Stn Ref-3 (69.883633°N, 19.43823°E), depth 55 m, 17 July 2006; collected by A. Sikorski; NHMUK Reg. No. 2015.2996. 1 ovigerous ♀ from Artacama proboscidea Malmgren, 1866 , Loppa, Stn D2-2 (70° 08.690’N, 22° 17.708’E), depth 242 m, 24 June 2006; collected by A. Sikorski; NHMUK Reg. No. 2015.2997.

British material examined: 1 ovigerous ♀ from Polycirrus plumosus, Loch Creran, Fish Farm B , depth unknown, 20 June 1992; NHMUK Reg. No. 2017.483. 1 ovigerous ♀ from P. plumosus, Firth of Forth Stn 60 (56° 06.21’N, 02° 40.14’W), depth 46 m, 22 March 2000; collected by Sue Hamilton. 1 ovigerous ♀ from P. plumosus, Loch Laxford, Stn 35 (58.39940°N, 05.08402°W), depth 48 m, 12 July 2001; collected by Sue Hamilton. 1 ovigerous ♀ from P. plumosus, Loch Sunart, Stn 14 (55.67300°N, 05.92693°W), depth 64 m, 0 4 August 2001; collected by Sue Hamilton. 1 ovigerous ♀ from Polycirrus sp., Isles of Scilly, ( APEM prolect 413059, Sample 8100), Stn GT 35 217, collected 2013 .

Differential diagnosis. As for genus.

Remarks. Levinsen (1878) described the ovigerous female of A. terebellae and made preliminary observations on its internal anatomy. Bresciani & Lützen (1972, 1974) studied this species in detail and discovered its cryptogonochoristic reproductive strategy. They also showed that the gross morphology of the female is highly variable and it is therefore difficult to confirm specific identity from morphological features alone.

Aphanodomus terebellae has a wide distribution at high latitudes in the northern Hemisphere, from Canada, Greenland, and Iceland, to the Kara Sea in Arctic Russia. Around the British Isles it has been recorded from the Irish Sea ( O’Reilly 1995) and in the North Sea off Northumberland ( O’Reilly & Geddes 2000). The prevalence of A. terebellae on Lanassa venusta in the southern Irish Sea varied between 13 and 55% ( O’Reilly 1995). The previously reported hosts are: Amphitrite cirrata (Müller, 1771, in 1776), Artacama proboscidea , Lanassa venusta , Nicolea venustula (Montagu, 1818) , N. zostericola Örsted, 1844 , Polycirrus medusa , P. plumosus , and Thelepus cincinnatus (Fabricius, 1780) . All known hosts belong to the family Terebellidae including the new host recorded here, Leaena abranchiata . Given the large number of reported hosts from two different subfamilies within the Terebellidae , it is possible that more than one species of Aphanodomus is present in the North Atlantic, but the relative paucity of morphological characters and the variability in gross morphology demonstrated by Bresciani & Lützen (1974), suggests that species differentiation will best be explored using molecular methods.