''Isorophus'' is an extinct genus of

Echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea ...

belonging to the class Edrioasteroidea. It is commonly found in deposits dating to the Ordovician period. There are several species, with one (''Isorophus cincinnatiensis'') being the official fossil of the city of

Cincinnati Cincinnati ( ) is a city in the U.S. state of Ohio and the county seat of Hamilton County. Settled in 1788, the city is located at the northern side of the confluence of the Licking and Ohio rivers, the latter of which marks the state line wit ...

in the US state of Ohio.

References

Edrioasteroidea Prehistoric echinoderm genera Ordovician echinoderms Paleozoic echinoderms of North America {{Paleo-echinoderm-stub