A new species of Pseudopecoelus von Wicklen, 1946 (Digenea: Opecoelidae) from the orange roughy Hoplostethus atlanticus Collett, 1889 (Trachichthyidae) from off southeastern Australia

A new species, Pseudopecoelus sewelli, is described from the deep-sea fish Hoplostethus atlanticus from off southeastern Australia. It is an elongate form with considerable variation in such important characters as the anterior vitelline extent, the sucker ratio and the egg-size. The features distinguishing this species from five related forms are combinations of the sucker ratio, egg-size, lobation of gonads, presence or absence of a cirrus-sac and the position of the genital pore.