Four species of Stephanostomum Looss, 1899 (Digenea: Acanthocolpidae) from Seriola dumerili (Risso) (Teleostei: Carangidae) in the western Mediterranean,including S. euzeti n. sp.

Four species of Stephanostomum are described from various sites in Seriola dumerili from off Corsica, France. S. ditrematis (Yamaguti, 1939), from the stomach, pyloric caeca and duodenum, has 36 circum-oral spines. S. seriolae Yamaguti, 1970 is considered a synonym of S. ditrematis. S. filiforme Linton, 1940, from the mid-intestine, has 43-46 circum-oral spines. S. petimba Yamaguti, 1970, from the rectum, has a 42 circum-oral spines. S. euzeti n. sp. has 49-51 circum-oral spines, and differs from worms with a similar anterior extent of the vitellarium and circum-oral spine number in details of the vitelline distribution and the distances between the gonads. Attention is drawn to the presence in the rectum of S. dumerili of sympatric species differentiated mainly on circum-oral spine number.