Trebius benzi n. sp. (Siphonostomatoida: Trebiidae) infecting Squalus acutipinnis Regan off South Africa.

Trebius Krøyer, 1838 currently consists of 15 accepted species all infecting elasmobranchs. Apart from two species, i.e. T. caudatus Krøyer, 1838 and T. latifurcatus Wilson, 1921, that have been reported from ten and eight host species, respectively, the other 13 species have each been reported from only one or two host species. Trebius benzi n. sp., collected from Squalus acutipinnis Regan, is described and illustrated after examination through stereo- and compound microscopes. This species can be distinguished from the other known species by a combination of characters including an abdomen that is shorter than the genital complex, a maxillule with an endite that consists of a single-tined dentiform process, sternal furca tines that are blunt and as long as the base, and the innermost spine of the last exopodal segment of leg 1 the shortest.