Amiiformes

The Amiiformes were once a large, diverse group of fishes that comprised three distinc subgroups: the families Amiidae and Sinamiidae, and the superfamily Caturoidei. Of this diversity, only a single species, the bowfin, Amia calva (in Amiidae) is alive today.

The bowfin is found throughout eastern and central North America in quiet, sluggish backwaters and swamps. It has a cylindrical body with thin, overlapping scales (unlike gars and other non-teleostean neopterygian fishes). The bowfin receives its common name from its elongate dorsal fin, which has a smoothly curved, or bowed, profile. The bowfin moves around the water column by undulating the dorsal fin in a wave-like fasion. Many fossil bowfins also have a similar elongated dorsal fin, while others have a much shorter, triangular dorsal fin. 

The Amiidae are known from the Cretaceous through to the present times and have been found on all continents except Australia and Antarctica, and are mostly known from freshwater environments although there are also some marine amiids. The Sinamiidae are known from freshwater Late Jurassic to Early Cretaceous deposits of Asia, primarily China. The Caturoidea (comprised of two families, the Caturidae and Liodesmidae) are known from the Late Triassic to Early Cretaceous of Europe and North America and are primarily marine.