Petalodontiformes ("thin-plate teeth") is an extinct order of marine

cartilaginous fish Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue. ...

related to modern day

chimaera Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively. A ...

found in what is now the

United States of America The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

and Europe.Lund, Richard, E. D. Grogan, and M. Fath. "On the relationships of the Petalodontiformes (Chondrichthyes)." Paleontological Journal 48.9 (2014): 1015-1029. Most species are known only from isolated teeth.Dalla Vecchia, Fabio Marco, and Museo Paleontologico Cittadino. "A new petalodont tooth (Chondrichthyes, Petalodontiformes) from the Lower Permian of the Carnic Alps (Friuli, NE Italy)." Bollettino della Società Paleontologica Italiana 39 (2000): 225-228. All fossils range from the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonif ...

to the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

, where they are presumed to have died out during the Permian/Triassic extinction event. The two best known species are '' Belantsea montana'', from the Carboniferous Bear Gulch,

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Colu ...

, and '' Janassa bituminosa'', from the

upper Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozo ...

of Europe, as whole fossil specimens have been found of these two.

References

Carboniferous cartilaginous fish Permian cartilaginous fish Mississippian first appearances Mississippian taxonomic orders Pennsylvanian taxonomic orders Cisuralian taxonomic orders Permian extinctions Prehistoric cartilaginous fish orders {{Paleo-cartilaginous-fish-stub