Contribution to the knowledge of species of the genus Stephanostomum Looss, 1899 (Digenea: Acanthocolpidae) from teleosts of the Western Mediterranean, with the description of S. gaidropsari n. sp.

Four species of the acanthocolpid genus Stephanostomum are redescribed from the digestive tract of teleosts in the Western Mediterranean: the type-species, S. cesticillum from Lophius piscatorius is described with a ventrally interrupted ring of 35 circum-oral spines and as lacking a uroproct; S. bicoronatum from Sciaena umbra has a ventrally interrupted ring of 31 circum-oral spines and a uroproct; S. pristis from Phycis phycis has an uninterrupted ring of 36 oral spines and no uroproct; S. minutum from Uranoscopus scaber has an uninterrupted ring of 36 oral spines and a uroproct. A new species, S. gaidropsari from Gaidropsarus mediterraneus, is described with an uninterrupted ring of 36 oral spines and an apparent uroproct. It differs from all other Stephanostomum species with similar oral spine numbers in the armament of the ejaculatory duct, and from various of these species by vitelline distribution, length of the genital atrium, oesophageal length and sucker-ratio.