An examination of a sample of European eels, Anguilla anguilla (L.), collected from Lake Bracciano near Rome in 1993, the only known European locality with the occurrence of the introduced swimbladder nematode Anguillicola novaezelandiae Moravec et Taraschewski, 1988, revealed for the first time the presence of two Anguillicola species, A. novaezelandiae and A. crassus. In view of the investigations carried out by current authors in Bracciano Lake in the years 1982-1992, it is apparent that the latter species has been introduced into the lake quite recently, where it quickly became a dominant species. The development of A. novaezelandiae was experimentally studied in the copepod intermediate host, Cyclops strenuus, for the first time. The copepods were infected with nematode second-stage larvae at 21-22°C; fully developed infective third-stage larvae were obtained 13 days p.i. The general morphology of individual larval stages of A. novaezelandiae was similar to that of larvae of the related species Λ. crassus.