Free-living marine nematodes from the Southern Bight of the North Sea: 1. Notes on species of the genera <i>Gonionchus</i> Cobb. 1920, <i>Neochromadora</i> Micoletzky, 1924 and <i>Sabatieria</i> Rouville, 1903

The intraspecific variation of some nematode species from the Southern Bight of the North Sea is discussed.A redescription (or amplification) is provided for following species: Gonionchus longicaudatus (Ward, 1972), Neochromadora angelica Riemann, 1976, N. munita Lorenzen, 1971, N. paratecta Blome, 1974, Sabatieria celtica Southern, 1914, S. longispinosa Lorenzen, 1972, S. punctata (Kreis, 1924).Following taxonomic changes are proposed: Gonionchus villosus sensu Vincx, 1981 nec Cobb, 1920 is synonymized with G. cumbraensis Benwell, 1981; Neochromadora paramunita Boucher, 1976 is synonymized with N. munita Lorenzen, 1972; Sabatieria strigosa Lorenzen, 1972 is synonymized with S. celtica Southern, 1914; Sabatieria mortenseni (Ditlevsen, 1921), S. breviseta (Stekhoven, 1935) and S. vulgaris sensu Gerlach (1965) and sensu Riemann (1966) (nec de Man, 1907) are synonymized with S. punctata (Kreis, 1924).Two new species are described: Gonionchus heipi sp.n., a species mainly characterized by its aberrant cuticular ornamentation and Neochromadora nicolae sp.n. a species characterized by a weak cuticular ornamentation, cephalic setae less than 50% of corresponding body diameter (c.b.d.), prominent dorsal stomatal bulb, prominent ventral gland and males with eight minute preanal supplements