REDESCRIPTION OF CERVIDELLUS-VEXILLIGER (DEMAN, 1880) THORNE, 1937 (NEMATODA, CEPHALOBIDAE) AND TAXONOMICAL CONSEQUENCES

Cervidellus vexilliger, presently the type species of the genus Ypsylo nellus is redescribed and a neotype selected from specimens in a sampl e collected at the type locality : the Haagse Bos, the Netherlands. Th e sample also yielded a second very similar species, agreeing with the diagnosis of C. neftasiensis. The original description of C. vexillig er and the new specimens described from the type locality, suggest tha t C. vexilliger is conspecific with C. serratus. C. serratus is theref ore synonymized with C. vexilliger and Ypsylonellus is synonymized wit h Cervidellus. Differential diagnoses and a provisional classification of the genera Cervidellus and Stegelletina are presented.