a1 Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH
A new species of mouthless and gutless free-living marine nematode, Astomonema southwardorum sp. nov., the dominant species from a methane seep pockmark in the North Sea, is described and illustrated. The new species is distinguished by its combination of short cephalic and cervical setae, with the latter being sparsely and irregularly distributed, and also in male specimens by its arrangement of precloacal and caudal setae and its postcloacal papillae. The genus Astomonema Ott, Rieger, Rieger & Enderes, 1982, is rediagnosed. Astomonema brevicauda (Vitiello, 1971) Vidakovik & Boucher, 1987, is considered to be a species inquirenda.