A taxonomic reconsideration of the genus Plagiorhynchus s. lat. (Acanthocephala : Plagiorhynchidae), with descriptions of South African Plagiorhynchus (Prosthorhynchus) cylindraceus from shore birds and P. (P.) malayensis, and a key to the species of the subgenus Prosthorhynchus

A population of Plagiorhynchus (Prosthorhynchus) cylindraceus (Goeze) Schmi dt and Kuntz is described from 4 species of shore birds in South Africa. Sp ecimens of 3 supposed synonyms of P. (P.) cylindraceus, namely P. (P.) form osus Van Cleave, P. (P.) taiwanensis Schmidt and Kuntz, and P. (P.) transve rsus (Rudolphi) Travassos, were studied and this synonymy was verified. The taxonomic status of Plagiorhynchus s. str. and of Prosthorhynchus was reco nsidered, and both were retained as subgenera. Females of Plagiorhynchus (P rosthorhynchus) malayensis (Tubangui) Schmidt and Kuntz (nec malayense) are described for the first time; males are redescribed. A key to species of t he subgenus Prosthorhynchus is provided.