Revision of Neoechinorhynchus Stiles & Hassall, 1905 (Acanthocephala: Neoechinorhynchidae) with keys to 88 species in two subgenera.

Neoechinorhynchus Stiles & Hassall, 1905 is revised based on both bibliographic studies and the examination of material. The evolution of the concept of the genus is discussed. The concept of Hebesoma Van Cleave, 1928 is also commented upon. The synonymy of the two genera is accepted, with Neoechinorhynchus having priority, and a new diagnosis for Neoechinorhynchus is provided. However, Hebesoma is recognised as a subgenus of Neoechinorhynchus, being differentiated from the nominal subgenus primarily on features of the egg. Of the 109 species studied, seven are transferred to other genera and 14 are considered invalid. Eleven species are assigned to the subgenus Hebesoma and 48 to the subgenus Neoechinorhynchus. Twenty-nine species were not assigned because of incomplete or absence of descriptions of adult females. Keys to assigned and non-assigned species are provided. Notes on the zoogeography of the 88 accepted species are also included.