Petalodontidae

Petalodontidae Temporal range: Lower Carboniferous to Permian
Teeth of Petalodus ohioensis (Carboniferous).
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Holocephali
Order:	†Petalodontiformes
Family:	†Petalodontidae Newberry & Worthen, 1866
Genera
†Ageleodus †Antliodus †Chomatodus †Ctenoptychius †Glyphanodus †Harpacodus †Lisogodus †Neopetalodus †Paracymatodus †Petalodus †Polyrhizodus †Serratodus †Siksika †Tanaodus[1]

Petalodontidae is an extinct family of marine cartilaginous fish related to the modern-day chimaeras, found in what is now the United States of America and Europe. With a very few exceptions, they are known entirely from teeth. All fossils range from the Carboniferous to the Permian, where they are presumed to have died out during the Permian/Triassic extinction event.