Eugeneodontida

Eugeneodontida is an extinct and poorly known order of bizarre cartilaginous fishes. They possessed a unique "tooth-whorl" on the symphysis of the lower jaw as well as pectoral fins supported by long radials. The palatoquadrate was either fused to the skull or reduced. Now determined to be within Holocephali, their closest living relatives are ratfish. The meaning of the name Eugeneodont correlates to "true origin teeth", and comes from the Greek words eu (good/true), geneos(race, kind, origin) and odon (tooth.)