Abstract
A single quillback Carpiodes cyprinus was collected with a boat electrofisher during May 2022 from the Verdigris River, Wagoner County, Oklahoma, USA. Its gills, gall bladder, fins, integument, musculature, and other major organs were macroscopically examined for myxosporeans. The gill rakers and gill lamellae were each infected with a new myxosporean, Myxobolus arkansasense sp. n., and Myxobolus verdigrisense sp. n., respectively. Qualitative and quantitative morphological data were obtained from fresh myxospores. Molecular data consisted of a 772 base pair sequence of the partial small subunit (SSU) ribosomal RNA gene for M. arkansasense sp. n. and a 1700 base pair sequence for M. verdigrisense sp. n. Phylogenetic analysis grouped Myxobolus arkansasense sp. n. and Myxobolus verdigrisense sp. n. with myxosporeans primarily known to infect North American catostomid fishes. To date, M. arkansasense sp. n is the only member of the genus known to infect the gill rakers of C. cyprinus.