Pterotocrinus acutus Crinoid Calyx With Snail

 

This picture is a recent fossil find from the Glen Dean Member of Grayson County, Kentucky USA. It is a crinoid calyx fossil that appears to be a Pterotocrinus acutus (Wetherby, 1879). The fossil dates to the Mississippian Period. 

The most interesting part of the fossil is when it photographed from the top revealing a gastropod was attached to its anal tube when they both died. A somewhat common relationship found in the fossil record between these two creatures.

Thanks to Kenny for the image.