This post concerns a fossil that I believe to be Catcocrinus glans (Hall), the youngest known species of this fossil crinoid genus, which is Early Carboniferous (i.e., Mississippian Period) in geologic age; thus it is about 350 million years old. This species is found in Missouri and Indiana. I include here an image of this particular crinoid (for the original illustration, see pl. 77, fig. 10 in Shimer and Schrock 1944:p. 196).
This fossil does not resemble traditional crinoids, or any other illustration of any fossil, other than that of Catcocrinus (note: I looked for a long time in every fossil book I have). The Mississippian age was a time of greatest crinoid diversity, and Catcocrinus seems to have been an example of a crinoid that took advantage of this diversification!
Figure 1. Actual specimen (6 3/4 cm tall and 5 cm wide) of this unusual crinoid.
Figure 2. Catcorinus glans (copied from pl. 77, fig. 10---in Shimer and Schrock, 1944:p.196) [also see their short text note on p. 193].
Main Reference
Shimer, H. W. and R. R. Shrock. Index fossils of North America. The M.I.T. Press, Cambridge, Massachusetts, 837 pp.
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