Myxosporidan parasites for pumpkinseed (Lepomis gibbosus L.) from Ontario.

Five species of myxosporideans were found in pumpkinseed (Lepomis gibbosus L.) from Ryan Lake, Algonquin Park, Ontario. Myxobolus osburni Herrick 1936 was found in pancreatic tissue. Myxobilatus ohioensis (Herrick 1941) Davis 1944 was found in the ureters and urinary bladder. Three new species are described, namely, Myxobolus uvuliferis sp. n. (in the fibrous capsule surrounding the metacercariae of Uvulifer ambloplitis (Hughes 1927), Myxobolus magnaspherus sp. n. (in the parietal peritoneum) and Myxobolus dechtiari sp. n. (in the gills). Myxobolus uvuliferis sp. n. is most similar to M. osburni, but its spores are subspherical and not spherical. Myxobolus magnaspherus sp. n. is most similar to Myxobolus gigas Auerbach 1906, but its spores are wider than long, and they have exceedingly long polar filaments. Myxobolus dechtiari sp. n. is similar to Myxobolus karelicus Petruschewsky 1940 but it lacks an intercapsular appendix.