This image shows what appears to be a Polygnathus longiposticus conodont fossil. This creature existed in the Mississippian Period. Fossil was found in the Jacob Chapel Shale of Clark County Indiana USA.
Source for ID is Conodonts of the Jacobs Chapel Shale by Carl B. Rexroad, Indiana Department of Natural Resources Geological Survey Bulletin 41 (published Bloomington Indiana 1969).
Thanks to Kenny for the image.
