Tarrasiiformes

Tarasiiformes is an extinct order of prehistoric ray-finned fish.

Taxonomy

 * Order †Tarrasiiformes sensu Lund & Poplin 2002 [Haplistia]
 * Family †Tarrasiidae Traquair 1881 emend. Woodward 1891
 * Genus †Apholidotos Lund ex Frickinger 1991 nomen novum
 * Species †Apholidotos ossna Lund ex Frickinger 1991 nomen novum
 * Genus †Paratarrasius Lund & Melton 1982
 * Species †Paratarrasius hibbardi Lund & Melton 1982
 * Genus †Tarrasius Traquair 1881
 * Species †Tarrasius problematicus Traquair 1881

Timeline of genera
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.