A new Myxidium (Cnidaria: Myxosporea: Myxidiidae) from the gallbladder of the yellow bullhead, Ameiurus natalis (Siluriformes: Ictaluridae), from Southwestern Arkansas, USA.

The yellow bullhead, Ameiurus natalis (Lesueur) is a moderately-sized member of the catfish family Ictaluridae Gill with a fairly large North American distribution. Between March and December 2021 and again between March 2022 and March 2023, 37 A. natalis specimens were collected from watersheds in Arkansas (n = 30) and Oklahoma (n = 7), USA, and their gills, gallbladders, urinary bladders, fins, integument, other major organs, and musculature were examined for myxosporeans. The gallbladder of a single individual yellow bullhead from Sevier County, Arkansas, USA, was infected with a novel myxosporean, Myxidium horatioense n. sp. and an unknown species of myxosporean. Qualitative and quantitative morphological data were from ethanol-preserved myxospores of M. horatioense n. sp. Molecular data consisted of 1,846 and 844 base pair sequences of the partial small subunit ribosomal RNA gene for M. horatioense n. sp. and an unidentified myxosporean, respectively. This is the first report of any member of the genus Myxidium from A. natalis. This article was registered in the Official Register of Zoological Nomenclature (ZooBank) as urn:lsid:zoobank.org:pub:urn:lsid:zoobank.org:act:92DC4EB0-3590-4EE0-8D90-D1279C52763B.