Echinodermata (Spiny-skinned animals)
Echinoderms include well-known sea animals like the starfish (Asteroidea), brittle stars (Ophiuroidea), sea urchins and sand dollars (Echinoidea), sea cucumbers (Holothuroidea), and sea lilies (Crinoidea). Fossils of all these classes of echinoderms plus the extinct classes Blastoidea (no common name) and Edrioasteroidea (no common name) have been found in Kentucky. By far the most abundant are the crinoid and blastoid fossils; fossils from the other classes are relatively rare.
Starfish (Asteroidea and Ophiuroidea)
Sea lilies (Crinoidea)
Blastoids, look like fossil hickory nuts (Blastoidea)
Edrioasteroides are an extinct group of echinoderms. The are usually disk shaped and lived attached to shells lying on the bottom of the sea. Although very rare, several have been found in Ordovician and Mississippian strata in Kentucky.
Echinoidea (Sea Urchins, Sand Dollars)
Echinoids are globe-shaped to disk-shaped echinoderms commonly covered with spines. They move about with their many tube feet on the sea bottom and eat algae. Their many spines are usually moveable. Echinoid fossils are common to rare from the Ordovician to the present. They have been found in the Ordovician through Pennsylvanian strata of Kentucky.
Pentagonal (5-part) symmetry