They are regarded as taxonomic relicts, being the sole surviving species of the order Amiiformes and clade Halecomorphi, which dates from the Triassic to the Eocene, persisting to the present.

These two genera, their sister amiine Pseudoamiatus, and the marine vidalamiine Maliamia were the only amiids, and halecomorphs as a whole, to survive the Cretaceous-Paleogene extinction event.

[7] Following the extinction event, Amia and Cyclurus survived in a refugium in western North America and experienced a rapid evolutionary radiation.

[1] During this time period, some species of Amia evolved very large body sizes, most notably A. basiloides, which is one of the largest holosteans known to have existed.

[7] The species 'Amia uintaensis' Leidy, 1873, which formerly contained several Amia specimens from western North America dating from the Late Cretaceous to the Eocene (including the holotype of A. basiloides), is considered a nomen vanum.