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Yellowstone National Park Report

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Diphyllobothrium cordiceps (Leidy, 1872) has been known from Yellowstone Lake fishes since 1872. Leidy described and named the species Dibothrium cordiceps from poorly preserved larval (plerocercoid) material collected from native trout, Salmo mykiss (= Salmo clarki) by members of the Hayden Expedition. The larval tapeworm has been reported only from cutthroat trout, Salmo clarki, brown trout, Salmo trutta, brook trout, Salvelinus fontinalis, and grayling, Thymallus arcticus, chiefly from Yellowstone Lake and adjacent waters in the northern Rocky Mountains. Simms and Shaw (1939), found cordiceps outside the Rocky Mountain area in brook trout from Elk Lake, western Deschutes County, Oregon.