Fossil Crinoid Halysiocrinus Tunicatus Edwardsville Formation Monroe County...

Description

Haylsiocrinus is an unusual disparid belonging to the group known as calceocrinitids. Calceocrinitids had an unusual lifestyle in that the crown laid along the seafloor as opposed to being held up by the stem. The calyx has a hinge that allows the crown to fold and unfold as the animal was feeding. You can see where the ligaments were on the back of the radial plates on these animals. Halysiocrinus is a rare crinoid up in crawfordsville but a pocket a friend and I found down in Monroe County to the south has produced a fair number of them.  This specimen is one of the best we have found, but in time we have found better for our own collections and have decided to part with this one. Even still, this is one of the largest we have found, measuring in at around 3 inches.