Tormopsolus attenuatus n. sp (Digenea : Acanthocolpidae) from Seriola hippos (Perciformes : Carangidae), Western Australia, with some observations onthe relationships in the genus

A new acanthocolpid, Tormopsolus attenuatus n. sp., is described from the c arangid Seriola hippos from waters off the coast of SW Australia. A cladist ic analysis of the genus using 31 morphological and metrical characters ind icates that the closest species is T. asiatica Parukhin, 1976 status amend. (previously T. orientalis asiatica). T. attenuatus differs from T. asiatic a in its smaller overall dimensions, more attenuated outline, relatively sh orter post-testicular region, vitelline interruption at the level of the ov ary, papillae on the oral sucker and, possibly, much longer genital atrium. Other similar species, T. orientalis Yamaguti, 1934 and T. medius Reimer, 1983, differ in having interruptions of the vitelline fields at the level o f both testes and at the level of the ovary.