''Colosteus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of colosteid

tetrapod A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetr ...

from the Late Carboniferous (late Westphalian stage) of

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

. 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 Mahoning County is located in the U.S. state of Ohio. As of the 2020 United States census, 2020 census, the population was 228,614. Its county seat and largest city is Youngstown, Ohio, Youngstown. The county is List of Ohio county name etymolo ...

. 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 mammals h ...

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 ''Pygopterus'' is an extinct genus of prehistoric bony fish that lived during the Wuchiapingian to Olenekian ages (late Permian to Early Triassic epochs) in what is now England, Germany (Baden-Württemberg, Saxony-Anhalt), Greenland and Svalbard ...

''. In 1869,

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontology, paleontologist, comparative anatomy, comparative anatomist, herpetology, herpetologist, and ichthyology, ichthyologist. Born to a wealthy Quaker fam ...

erected a new genus of "

batrachian A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough skin texture due to ...

", ''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 (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

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 In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

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

References

Colosteidae Pennsylvanian sarcopterygians of North America Extinct animals of the United States Fossil taxa described in 1871 Taxa named by Edward Drinker Cope {{paleo-tetrapodomorph-stub