Caryophyllidean tapeworms (Cestoda) are widespread parasites of suckers (Catostomidae) in North America, but their phylogenetic relationships remain poorly understood. This study presents molecular data on species of the recently established genus Pseudoglaridacris Oros, Uhrovič et Scholz, 2018. The type species, P. laruei (Lamont, 1921), a very common parasite of the white sucker Catostomus commersonii (Catostomidae) in North America, is characterised both molecularly and morphologically based on recently collected, properly fixed specimens from the type host (C. commersonii) and four species of redhorse (Moxostoma spp.), including new host and geographical records from Canada and the United States. Pseudoglaridacris laruei differs from other species in the genus by its size, being the largest species (body length up to 12.7 mm), a high number of testes (62–119) and very few (0–6) postovarian vitelline follicles. Mackiewiczus etowanum from Hypentelium etowanum and Mackiewiczus rarus from Moxostoma poecilurum in Alabama are nomina nuda. The taxonomic status of P. confusa (Hunter, 1929), which occurs in ictiobines, and of P. oligorchis (Haderlie, 1953), which is most probably a junior synonym of P. laruei with a reduced number of testes, is also discussed, based on molecular data indicating the presence of a putative new species from ictiobines that has not yet been described.
Supplementary Information: The online version contains supplementary material available at 10.1007/s00436-026-08648-8.
Keywords: lsrDNA; Caryophyllidea; Catostomidae; Morphology; Nearctic region; Tapeworms.