From Ohio History Central
The Upper Ordovician edrioasteroid Cystaster stellatus on a cobble from the Kope Formation in northern Kentucky. In the background is the cyclostome bryozoan Corynotrypa.
Among several groups of rare echinoderms known from Ohio are edrioasteroids, which are small, circular animals with starfish-like arms on the dorsal surface. They are usually found attached to the shell of a brachiopod or other shelled invertebrate.
- Ausich, W. I., 1996. "Phylum Echinodermata," in Fossils of Ohio, edited by R. M. Feldmann and Merrianne Hackathorn. Ohio Division of Geological Survey Bulletin 70, p. 242-261.