A new Microsporidium sp (microsporidia) from the musculature of the mountain whitefish Prosopium williamsoni from British Columbia: Morphology and phylogeny

Few microsporidia have been reported from whitefish species (subfamily Core goninae). For the most part, these microsporidia have been incompletely des cribed. In a survey of parasites of mountain whitefish Prosopium williamson i collected from Kootenay Lake, British Columbia, we encountered an unusual microsporidium infecting the endomysium of the skeletal musculature. Spore s were uninucleate, ovoid to pyriform, and were 5.6 (5-7) mu m X 3.2 (3-4) mu m with 13-16 coils in the polar filament. We describe here this organism as a new species based on its site of development and its relationship amo ng fish microsporidia based on small subunit ribosomal DNA sequence data, i .e., our analysis showed that it is not closely related to other microspori dia for which ribosomal DNA sequence is available thus far.