Sclerodistomoides pacificus Kamegai, 1971 (Sclerodistomoididae Gibson & Bray, 1979) and Tetrochetus coryphaenae Yamaguti, 1934 (Accacoeliidae Odhner, 1911), two rarely reported digeneans from Tylosurus acus imperialis (Rafinesque) (Belonidae), and a list of helminth parasites of Tylosurus acus (Lacépède).

Two rarely reported digenean parasites are redescribed: Sclerodistomoides pacificus Kamegai, 1971 (Sclerodistomoididae Gibson & Bray, 1979) from the gall bladder and Tetrochetus coryphaenae Yamaguti, 1934 (Accacoeliidae Odhner, 1911) from the digestive tract of the Mediterranean needlefish Tylosurus acus imperialis (Rafinesque) off Tunisia. Sclerodistomoides pacificus and T. coryphaenae represent new host and geographical records for T. a. imperialis off the Tunisian coast. A complete list of the helminth parasites found in T. a. imperialis and those reported from other subspecies of Tylosurus acus (Lacépède) throughout their wide distributional range is presented. It includes data for T. a. acus (Lacépède), T. a. imperialis, T. a. melanotus (Bleeker) and T. a. rafale Collette & Parin and comprises 46 parasite taxa. Among these, 15 species were recorded from T. a. imperialis off Tunisia.