7 April finds me painting until the last shreds of daylight on the inner shell of the female of Epioblasma torulosa, after having finished and photographed the outer shell of the male this afternoon. I thought I'd post a finished one this time, so here is the male.
The official Species At Risk website of Fisheries and Oceans Canada tells us that this species requires well oxygenated, clean water with a gravelly bottom, and is now extirpated from 95% of its former range in North America over the last century, and it is now known from only the Sydenham and Ausable rivers in southwestern Ontario. The site also says:
The Northern Riffleshell is sensitive to pollution from municipal, industrial and agricultural sources. Siltation, habitat perturbation and impoundment of rivers has also likely destroyed much of the habitat for this species over the last century. More recently, the Zebra Mussel (Dreissena polymorpha) has devastated Great Lakes populations. Access to suitable host species may also threaten this species.