Description of Neoechinorhynchus pikensis n. sp. (Acanthocephala: Neoechinorhynchidae) from Catostomus commersoni (Lacépède) in Wisconsin, USA

Abstract

Neoechinorhynchus pikensis n. sp. is described from one whole-mounted male specimen that was collected a few decades ago but went missing. It was collected from an individual white sucker, Catostomus commersoni (Lacépède) captured in the Pike River, Kenosha County and has never been found subsequently despite the examination of many collections of white suckers since. It is distinguished from other species of Neoechinorhynchus Stiles and Hassall, 1905 by a combination of the following diagnostic characters: Trunk small, straight anteriorly but slightly curled ventrad posteriorly; body wall with similar thickness dorso-ventrally; cuticle of proboscis and neck conjoined as one sheet of thick, dark chitin-like layer; proboscis wider than long with long anterior hooks with short round roots; hooks in second and third circles much smaller and rootless; receptacle three times as long as proboscis with a triangular cephalic ganglion at its base; lemnisci relatively long and equal, not reaching anterior testis; all male reproductive structures contiguous in posterior two thirds of trunk; testes pre-equatorial; anterior testis larger than posterior testis; large syncytial cement gland with 10 giant nuclei; cement reservoir prominent branching in 2 long cement ducts surrounding Saefftigen’s pouch. Comparisons with worldwide and North American related species that have partially similar features are made. It is proposed that the holotype may be part of a larger population in southwest Lake Michigan where the Pike River flows and where a continuous population of C. commersoni survives.