Edrioasteroids are rare, beautiful, and popular fossils to collectors and professional paleontologists. They show their affinities with other echinoderms in having obvious pentaradial symmetry (structures repeat in a circle 5 times).
Here’s a perfect Streptaster vorticellatus (Hall, 1866) edrioasteroid from the Cincinnatian outcrop belt of northern Kentucky, USA. It is encrusting a hardground (the same hardground horizon that has produced abundant specimens of the hyper-rare edrio. Carneyella ulrichi).
Classification: Animalia, Echinodermata, Echinozoa, Edrioasteroidea, Hemicystitidae
Stratigraphy: ~6 to 7 meters above base of Bellevue Formation (part of the “Grant Lake Formation”), Maysvillian Stage, middle Cincinnatian Series, middle Upper Ordovician
Locality: southern end of larger Maysville West roadcut (western side), northern Mason County, Kentucky, USA
Streptaster vorticellatus (13 mm across) from the Bellevue Formation (Upper Ordovician) at the Maysville West roadcut of northern Kentucky, USA.