Rhipidocotyle tridecapapillata n. sp. and Prosorhynchoides potamoensis n. sp. (Digenea: Bucephalidae) from Inland Fishes in Mississippi, U.S.A.

摘要

Rhipidocotyle tridecapapillata n. sp. is described from the intestine of the white bass, Morone chrysops (Rafinesque, 1820), from the Luxapalila River in Lowndes County, Mississippi, U.S.A. The new species has 13 papillae that protrude laterally from the anterior rim of the dorsal lobe of the rhynchus, enabling easy differentiation from the only known freshwater North American congeners, Rhipidocotyle papillosa (Woodhead, 1929), which has 15 papillae, and Rhipidocotyle septpapillata Krull, 1934, which has 7 papillae. Prosorhynchoides potamoensis n. sp. is described from the pyloric ceca and intestine of the white crappie, Pomoxis annularis Rafinesque, 1818, from the Pascagoula River in Jackson County, Mississippi, U.S.A. The new species differs from the only other North American freshwater congener, Prosorhynchoides pusilla (Stafford, 1904), by having the anterior half of the body wider than the posterior body half rather than having a cylindrical body; a rhynchus-width to body-width ratio of 1:2.5^.0 compared with K0.8-1.3; a pre-equatorial rather than equatorial mouth; a larger pharynx, testes, and ovary; and the Mehlis' gland located between the testes rather than immediately posterior to the ovary as in P. pusilla and most of the North American marine species in Prosorhynchoides. New combinations are created for 9 species of North American bucephalids belonging in Prosorhynchoides Dollfus, 1929.