Dunkleosteus terrelli, a species of extinct arthrodire placoderm fish that lived in the seas that covered parts of Ohio during the Late Devonian period, about three hundred fifty-nine to three hundred eighty-two million years ago, is hereby adopted as the official fossil fish of the state.
State fossil fish
Ohio Rev. Code Ann. § 5.078, under Chapter 5 | State Insignia; Seals; Holidays.
Ohio Rev. Code Ann. § 5.078