| Tarrasiiformes Temporal range: | |
|---|---|
| †Paratarrasius hibbardi Lund and Melton Jr. 1982 from the Mississippian (Serpukhovian) Heath Formation of Bear Gulch, Montana | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | †Tarrasiiformes |
| Families | |
| |
Tarrasiiformes is an extinct order of prehistoric ray-finned fish.

Tarrasius is an extinct genus of Tarasiiformes. Tarrasius problematicus (of Mississippian origin, ~ 350 Ma) featured a fully regionalized tetrapod-like spine divided into 5 distinct segments. It is not considered a transitional fossil though, but an extreme example of convergent evolution.
{{cite journal}}: Cite journal requires |journal= (help)