Acanthonotozoma Serratum, an Arctic Amphipod New to Britain

Extract

The amphipod family Acanthonotozomatidae was represented hitherto in British waters by the generaIphimedia Rathke (includingPanoploea Thompson) andOdius Lilljeborg; Acanthonotozoma Boeck being unrecorded (Lincoln, 1979).

Material referable toAcanthonotozoma serratum (O. Fabricuius, 1780) is here reported from the East coast of Scotland. Two specimens (1 juvenile,ca. 7 mm long and 1 immature female, broken in half, estimated length 85 mm) were taken by Dr R. Earll by diving (his sample no. CR2, St. 4/3) from amongst tubes occupied by the amphipodEricthonius rubricornis Stimpson attached to boulders amongst coarse sand, depth 345 m, at Coldingham Bay, St Abbs, Berwickshire, Scotland (55° 53' 30": 2° 5' 36") on 17 August 1982. Dr Earll kindly made over his amphipod material to me for identification.

Just (1978) has reviewed the genusAcanthonotozoma and has commented on the variability of both morphology and coloration ofA. serratum from Greenland, Iceland, Spitzbergen, Russian Kara Sea, N. Norway and the Skagerrak. The Scottish material has Norwegian rather than Greenlandic characteristics. Thus the dorsal tooth on peraeonite 5 is lacking, giving the dorsum a 4-dentate appearance. Coxal plate 3 is bluntly tapered distally. Coxal plate 4 is squarish and coxal plate 7 has the posterodistal corner unproduced. The posterodistal projections of the third epimeral plate are short with a wide angle between them. The basal articles of peraeopods 57­ have a square, less sharply produced posterodistal corner.

Mouthparts and anterior peraeopoda have been dissected from the right side of the female and mounted on three slides in polyvinyl-lactophenol. No significant differences are apparent in mouthpart morphology compared with fig. 4 in Just (1978).