''Colosteus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of colosteid

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct t ...

from the Late Carboniferous (late Westphalian stage) of

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

. Its remains have been found at the Linton site in Saline Township, Ohio, where it is one of the most common tetrapods, and at the Five Points site in Mahoning County, Ohio. It was an elongate, aquatic form with a flattened and pointed head, greatly reduced limbs, two

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

ry tusks, and heavy scalation. It would have reached about 1 m (3.2 ft) in length. It was originally described by

John Strong Newberry John Strong Newberry (December 22, 1822 – December 7, 1892) was an American physician, geologist and paleontologist. He participated as a naturalist and surgeon on three expeditions to explore and survey the western United States. During the C ...

in 1856 as a new species of the palaeonisciform fish

'' Pygopterus''. In 1869, Edward Drinker Cope erected a new genus of " batrachian", ''Colosteus'', containing the species ''C. crassicutatus'', ''C. foveatus'', and ''C. marshii'', based on Linton material lent to him by Newberry. Cope later realized that the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

of his ''Colosteus crassicutatus'' was also the holotype of Newberry's earlier ''Pygopterus scutellatus'', and combined the two as ''Colosteus scutellatus''. ''Colosteus foveatus'' was later determined to be a junior synonym of ''

Isodectes ''Isodectes'' is an extinct genus of dvinosaurian temnospondyl within the family Eobrachyopidae. The genus ''Saurerpeton'', named in 1909, is considered to be a junior synonym The Botanical and Zoological Codes of nomenclature treat the concep ...

obtusus'', and ''Colosteus marshii'' was given its own genus, '' Ptyonius''

References

Extinct animals of the United States Carboniferous tetrapods of North America Fossil taxa described in 1871 Taxa named by Edward Drinker Cope {{paleo-amphibian-stub