Myxobolus cognati n. sp. (Myxosporea) from the opercular integument of Cottus cognatus (Cottidae) in Lake Michigan

A myxosporean producing aggregations of white pseudocysts in skin covering the posterior margin of the operculum and perioral tissue of Cottus cognatus in Lake Michigan is described as Myxobolus cognati n. sp. (Myxosporea). Histological sections revealed that the parasite develops in vascularized regions of the dermis and with development protrudes beyond the surrounding skin surface. Myxobolus cognati resembles Myxobolus rhinichthidis Fantham, Porter and Richardson, 1939 from subepithelial tissue of the operculum of the cyprinid Rhinichthys cataractae. Spores in the 2 species are the same size and shape. However, in contrast to those of M. cognati, spores of M. rhinichthidis have filament coils wound loosely at 45A? to the axis of the polar capsule and have no natural sutural ridge folds.