A New Species of Thorny-headed Worm (Acanthocephala: Neoechinorhynchus), a Parasite from Two Species of Redhorse Fish (Catostomidae: suckers) in North America

Abstract

We encountered a new species of Neoechinorhynchus (Acanthocephala) during extensive fish parasite survey work in North America that focused on catostomid fishes (suckers). Among our samples of Moxostoma specimens from the Red River in Manitoba, Canada, the Kanawha River in West Virginia, and the Allegheny River in Pennsylvania we encountered specimens of genus Neoechinorhynchus inconsistent with previously known species. All fish utilized in this study were captured via boat electroshocking, and subsequently examined with a dissecting microscope for parasitic worms. All acanthocephalans encountered were stored in tap water and after ~24 hours switched to 70% ethanol. They were then stained and mounted onto slides with Canada Balsam and subsequently examined with a Leica DM 2500 microscope. Measurements of 9 male and 12 female specimens of this new species were then compared to available published data for other North America fish-parasitizing species of Neoechinorhynchus, and in some cases, to type specimens. This new species differs from all but six of the 30+ species of Neoechinorhynchus from the USA and Canada in its possession of body walls that are thicker dorsally than ventrally, and in having lemnisci that are markedly unequal in length. Although the new species is similar to N. buckneri, N. bullocki, N. carinatus, N. cristatus, N. prolixoides, and N. prolixus in terms of body wall thickness and lemnisci, it can be distinguished from each of those species based on hook lengths of anterior, middle, and posterior hooks on the proboscis. Our morphologically-based conclusion that that this species is distinct from each of those 6 species is corroborated by sequence data for the large ribosomal subunit obtained in another ongoing study. Our study calls attention to the potential for more discovery of novel species in North America.