Polypodium sp. is reported for the first time from Canadian waters. It occurred in lake sturgeon (Acipenser fulvescens) eggs, from the Nelson River, Manitoba, and from Cumberland House, Saskatchewan. The prevalence of this parasite was 100% in females with eggs of 3.0 mm diameter or more. One, 4, 25, and 179 infected eggs were collected in gonads with eggs of this size class, but infected eggs were not apparent in individuals with smaller eggs. This is the northernmost occurrence of this parasite reported in North America.
1989. The occurrence of Diplostomum spathaceum metacercariae in the freshwater drum, Aplodinotus grunniens. Can. J. Zool. 67: 2853Zool. 67: -2856 Strigeoid metacercariae from the lenses of freshwater drum, Aplodinotus grunniens, were morphometrically analyzed and compared with those of the North American subspecies of Diplostomum spathaceum: Diplostomum spathaceum indistinctum and Diplostomum spathaceum huronense. The metacercariae resembled D. s. indistinctum in mean body length, mean body width, oral sucker size, and holdfast size. Prevalence of infection in drum was 99% and intensity ranged from 0 to 260 worms per fish (mean f SD = 35 + 32). A significant difference (P < 0.05) in mean intensity between male and female fish was observed, with females harboring a greater worm burden (i.e., 43 in females versus 24 in males). Differences in infection intensity between left and right lenses from all fish were not significant (P > 0.05); however, the degree of asymmetry between left and right lenses of individual fish was highly significant (P < 0.005) according to heterogeneity X2 analysis. In this case, neither left nor right lenses were consistently favored. LENO, G. H., et HOLLOWAY, H. L., JR. 1989. The occurrence of Diplostomum spathaceum metacercariae in the freshwater drum, Aplodinotus grunniens. Can. J. Zool. 67 : 2853 -2856. Des mktacercaires strigCoi'des trouvCes dans le cristallin de Malachigans, Aplodinotus grunniens, ont Ct C soumises ?I une analyse morphomCtrique et comparkes aux sous-espkces nord-amCricaines de Diplostomum spathaceum : Diplostomum spathaceum indistinctum et Diplostomum spathaceum huronense. Les mdtacercaires trouvCes ressemblaient ?I D. s. indistinctum par la longueur moyenne, la largeur moyenne, la taille de la ventouse orale et de la ventouse ventrale. Quatre-vingt-dix-neuf pourcent des poissons Ctaient infect& et on pouvait compter de 0 5 260 vers par poisson (moyenne f Ccart type = 35 + 32). I1 y avait une diffkrence significative (P < 0,05) entre le fardeau de parasites des mAles et celui des femelles et ce sont les femelles qui Ctaient le plus affectCes (43 vs. 24). Les diffkrences entre le fardeau de parasites du cristallin gauche et celui du cristallin droit n'ktaient pas significatives (P > 0,05), mais cependant l'importance de 1'asymCtrie entre le cristallin droit et le cristallin gauche de certaine individus Ctait trks significative (P < 0,005) d'aprks une analyse d'hCtCrogCnCitk baske sur le x2. Cette asymCtrie n'affectait cependant pas un cristallin plus que l'autre de facon constante.[Traduit par la revue]
Polypodium hydriforme, a parasitic coelenterate infecting oocytes of acipenserid fishes, is reported from the upper Missouri River drainage. This finding extends the known distribution of P. hydriforme northward from the Osage River near Jefferson City, Missouri. Polypodium hydriforme has also been recovered from the Lake Huron drainage. The parasite was found in eggs from 4 of 5 artificially spawned paddlefish Polyodon spathula in South Dakota and North Dakota, and 6 of 19 paddlefish, untreated with hormones, at Intake, Montana. Less than 1% of the paddlefish eggs were infected. Although there are few specific characteristics for identification, the form morphometrically and histologically analyzed agrees with the description off. hydriforme.
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