The Amiiformes order of fish has only two extant species, the bowfins: Amia calva and Amia ocellicauda, the latter recognized as a separate species in 2022. 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.
Semionotiformes is an order of ray-finned fish known from the Middle Triassic (Anisian) to the Late Cretaceous (Maastrichtian). Their closest living relatives are gars (Lepisosteidae), with both groups belonging to the clade Ginglymodi within the Holostei. The group includes both freshwater (Semionotidae) and marine adapted forms. Many members of the family Macrosemiidae, had elongated dorsal fins, often associated with an adjacent area of skin which was free of scales. These fins were likely undulated for use in precision swimming. The body morphology of macrosemiids suggests that they were slow swimmers who were capable of maneuvering around complex topography, such as reef environments.
Holostei is a group of ray-finned bony fish. It is divided into two major clades, the Halecomorphi, represented by the single living genus, Amia with two species, the bowfins, as well as the Ginglymodi, the sole living representatives being the gars (Lepisosteidae), represented by seven living species in two genera. The earliest members of the clade, which are putative "semionotiforms" such as Acentrophorus and Archaeolepidotus, are known from the Middle to Late Permian and are among the earliest known neopterygians.
Cleithrolepis is an extinct genus of freshwater ray-finned fish that lived from the Induan age to the Anisian in what is now Australia and Libya. A species from Late Triassic Germany, C. brueckneri, was also ascribed to Cleithrolepis.
Chongichthys is an extinct genus of prehistoric marine ray-finned fish that lived during the Oxfordian stage of the Late Jurassic epoch. It contains one species, C. dentatus from the Quebrada El Profeta of Chile. It is named after Chilean geologist Guillermo Chong.
Luisiella is an extinct genus of prehistoric bony fish that lived during the Kimmeridgian stage of the Late Jurassic epoch. Fossils of the genus have been found in either the Cañadón Calcáreo Formation or Cañadón Asfalto Formation in Chubut Province, Argentina.
Pteronisculus is an extinct genus of prehistoric ray-finned fish that lived during the Early Triassic and Middle Triassic epochs of the Triassic period worldwide.
Gyrolepidoides is an extinct genus of prehistoric bony fish that lived during the Late Triassic epoch in what is now Mendoza, Argentina.
Cosmoptychius is an extinct genus of freshwater and estuarine ray-finned fish that lived during the Mississippian epoch. It contains a single species, C. striatus from the Visean of Scotland. It has a wide stratigraphic range in the Wardie Shale, with many specimens known.
Austropleuropholis is an extinct genus of freshwater ray-finned fish that lived during the Middle Jurassic epoch. It contains a single species, A. lombardi, from the Democratic Republic of the Congo, from the terrestrial/freshwater series of the Stanleyville Formation.
Boreosomus is an extinct genus of Triassic marine ray-finned fish. It was first described from the Arctic island of Spitsbergen, hence its genus name, but was later also discovered in other parts of the world. The type species is Boreosomus arcticus.
Cosmolepis is an extinct genus of prehistoric marine ray-finned fish that lived during the Early Jurassic epoch. It contains a single species, C. ornatus from the Blue Lias in what is now England. It is the only member of the family Cosmolepididae.
Coccolepis is an extinct genus of prehistoric marine ray-finned fish in the family Coccolepididae. Originally including most species within the family, it is now restricted to two species from the Late Jurassic Solnhofen Limestone of Germany. The holotype of C. bucklandi, designated and described by Louis Agassiz, was thought to be lost but was later rediscovered in Neuchâtel.
Chardonius is an extinct genus of prehistoric freshwater ray-finned fish from the late Aptian or early Albian. It contains a single species, C. longicaudatus, from the Loia Beds of the Democratic Republic of the Congo.
Ptycholepiformes are an extinct order of prehistoric ray-finned fish that existed during the Triassic period and the Early Jurassic epoch. The order includes the genera Acrorhabdus, Ardoreosomus, Boreosomus, Chungkingichthys, Ptycholepis, and Yuchoulepis. Although several families have been proposed, some studies place all these genera in the same family, Ptycholepididae.
The Los Rastros Formation is a mid-Carnian fossiliferous formation of the Agua de la Peña Group, in the Ischigualasto-Villa Unión Basin of northwestern Argentina. Fossil archosaur tracks, as well as many insects, fish, bivalves, crustaceans and plants have been reported from the formation.
Candelarialepis is an extinct genus of prehistoric marine ray-finned fish that lived during the Induan age of the Early Triassic epoch in what is now Nevada. It contains a single species, C. argentus. It was described from the Candelaria Formation.
Ardoreosomus is an extinct genus of marine ray-finned fish. It was described from the Induan aged Candelaria Formation of Nevada, United States, which was located near the equator during the Early Triassic epoch. It contains only one species, A. occidentalis (monotypy).
Turseodus is an extinct genus of ray-finned fish found in Late Triassic freshwater sediments of the United States. Two species have been described, T. acutus from the Lockatong Formation of Pennsylvania, and T. dolorensis from the Chinle Formation of Colorado.
Brazilichthys is an extinct genus of prehistoric freshwater ray-finned fish that lived during the Cisuralian epoch in what is now Maranhão, Brazil. The type and only species, B. macrognathus, is known from a single partially complete skull, which was recovered from the Pedra de Fogo Formation near Pastos Bons, Maranhão, Brazil.
