Now, I don't know if the two youngest and I were finding Wabash pigtoes or muckets (Actinonaias ligamentina) while wading the Kankakee River Thursday. (See post by Kevin Cummings at end.)
Karyla K. Trester, webmaster for the Illinois Natural History Survey, sent this:
The Illinois Natural History Survey has an On-line mussel identification guide that you may be interested in. Here is the URL:http://www.inhs.illinois.edu/animals_plants/mollusk/fieldguide.html
You can use the navigation buttons to flip through the "pages."
I'm not a genius, so it took a bit, but the key page as a starting point I think is this page with the scientific names and common names.
An IDNR official, who must have been taking a break from more pressing matters and reverting to old loves, sent this:
Dale, regarding your photo of K3 mussels, it is hard to tell, but they look like Wabash pigtoes. This is a fairly common species. K3 has a lot of good mussel fauna diversity and some interesting rare ones - elktoe, black sandshell...
How can you not enjoy the possibility that they were pigtoes. I can't wait to tell my kids.
Click here for the INHS page on the Wabash pigtoe.
As to black sandshell, I am certain I have come across them occasionally while playing around the Kankakee.
I don't think I've seen an elktoe. That strikes me as one I would have remembered.
Now I have to pay more attention.
Now Cummings suggests it is something else.
What you have are muckets, Actinonaias ligamentina, the most common and abundant mussel in the Kankakee (not common elsewhere though).