| Cosmoptychius Temporal range: | |
|---|---|
| Specimen of C. striatus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Family: | †Cosmoptychiidae Gardiner, 1963 |
| Genus: | †Cosmoptychius Traquair, 1877 |
| Species: | †C. striatus |
| Binomial name | |
| †Cosmoptychius striatus (Agassiz, 1835) | |
| Synonyms | |
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Cosmoptychius is an extinct genus of freshwater and estuarine ray-finned fish that lived during the Mississippian epoch. It contains a single species, C. striatus from the Visean of Scotland. It has a wide stratigraphic range in the Wardie Shale, with many specimens known.
Initially classified as either a palaeonisciform (a now-paraphyletic group of basal actinopterygians) or the earliest stem-group neopterygian, it is now generally considered a stem-group actinopteran.