The Amiiformes/ˈæmi.ɪfɔːrmiːz/orderoffish has only two extantspecies, the bowfins: Amia calva and Amia ocellicauda, the latter recognized as a separate species in 2022.[2] These Amiiformes are found in the freshwater systems of North America, in the United States and parts of southern Canada. They live in freshwater streams, rivers, and swamps. The order first appeared in the Triassic, and the extinct members include both marine and freshwater species, many of which are morphologically disparate from bowfins, such as the caturids.
The extinct species of the Amiiformes can be found as fossilsinAsia and Europe, but the bowfin is the last living species in the order. Amiiformes is therefore the last surviving orderofHalecomorphi, the clade to which the bowfin and its fossil relatives belong. Other orders, such as the Parasemionotiformes, are all extinct.
Possible specimens of caturoids are known from the Late Triassic, with the earliest unambiguous members being known from the Early Jurassic.[4] Amiiformes had spread to North America and Africa by the end of the Middle Jurassic, reaching an apex of diversity during the Early Cretaceous, during the Late Cretaceous and Cenozoic, the group declined until only a single genus, Amia, containing the bowfin remained.[5]
^Sun, Zuoyu; Tintori, Andrea; Xu, Yaozhong; Lombardo, Cristina; Ni, Peigang; Jiang, Dayoung (April 2017). "A new non-parasemionotiform order of the Halecomorphi (Neopterygii, Actinopterygii) from the Middle Triassic of Tethys". Journal of Systematic Palaeontology. 15 (3): 223–240. doi:10.1080/14772019.2016.1181679. S2CID133176227.
^Forey, P. L.; Patterson, C. (2006). "Description and systematic relationships of † Tomognathus , an enigmatic fish from the English Chalk". Journal of Systematic Palaeontology. 4 (2): 157–184. doi:10.1017/S1477201905001719. S2CID86028273.
^Cavin, L.; Suteethorn, V.; Buffetaut, E.; Claude, J.; Cuny, G.; Le Loeuff, J.; Tong, H. (2007). "The first sinamiid fish (Holostei: Halecomorpha) from Southeast Asia (Early Cretaceous of Thailand)". Journal of Vertebrate Paleontology. 27 (4): 827–837. doi:10.1671/0272-4634(2007)27[827:TFSFHH]2.0.CO;2. S2CID85325978.