Palaeoniscum is an extinct genus of ray-finned fish from the Permian period (Guadalupian-Lopingian) of England, Germany, Turkey, North America and Greenland, and possibly other regions. The genus was named Palaeoniscum in 1818 by Henri Marie Ducrotay de Blainville, but was later misspelled as Palaeoniscus by Blainville and other authors. Palaeoniscum belongs to the family Palaeoniscidae.
The Palaeonisciformes, commonly known as "palaeoniscoids" are an extinct grouping of primitive ray-finned fish (Actinopterygii), spanning from the Silurian/Devonian to the Cretaceous. They are generally considered paraphyletic, but their exact relationships to living ray-finned fish are uncertain. While some and perhaps most palaeoniscoids likely belong to the stem-group of Actinopteryii, it has been suggested that some may belong to the crown group, with some of these possibly related to Cladistia and/or Chondrostei. Many palaeoniscoids share a conservative body shape and a similar arrangement of skull bones.
Birgeria is a genus of carnivorous marine ray-finned fish from the Triassic period. Birgeria had a global distribution, with fossil known from Madagascar, Spitsbergen, Germany, Switzerland, Italy, Slovenia, China, Russia, Canada and Nevada, United States. The oldest fossils are from Griesbachian aged beds of the Wordie Creek Formation of East Greenland. Birgeria existed throughout the entire Triassic period, from the very beginning just after the Permian-Triassic mass extinction, up to the very end with its extinction during the Triassic-Jurassic mass extinction.
Laugia is an extinct genus of coelacanth fish which lived during the Induan age of the Early Triassic epoch in what is now Greenland. The type and only species, Laugia groenlandica, was collected from the Wordie Creek Formation and described by Erik Stensiö. The genus is named after Lauge Koch.
Helmolepis is an extinct genus of ray-finned fish that lived during the Early Triassic epoch in what is now Greenland, Madagascar and Canada. Species of Helmolepis are small. This genus is closely related with Platysiagum.
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.
Acrolepis is an extinct genus of prehistoric marine bony fish that lived from the Famennian stage of the Devonian to the early Triassic epoch. Some species from the Early Triassic of Tasmania are also ascribed to Acrolepis.
Mylacanthus is an extinct genus of prehistoric coelacanth lobe-finned fish that lived during the Smithian age of the Early Triassic epoch in what is now Svalbard.
Sassenia is an extinct genus of prehistoric coelacanth lobe-finned fish that lived during the Early Triassic epoch in what is now East Greenland and Svalbard.
Bobasatrania is an extinct genus of prehistoric bony fish that survived the Permian-Triassic extinction event. Fossils of Bobasatrania were found in beds of Changhsingian to Ladinian age. It was most speciose during the Early Triassic.
Boreosomus is an extinct genus of Triassic ray-finned fish. It was first described from the Arctic island of Spitsbergen, but was later also discovered in other parts of the world. The type species is Boreosomus arcticus.
Colobodus is an extinct genus of Triassic bony fish of the family Colobodontidae and order Perleidiformes. Fossils have been found in Europe and China. It could reach body lengths of about 70 cm.
Urosthenes is an extinct genus of prehistoric bony fish that lived during the Lopingian to Middle Triassic epochs in what is now New South Wales, Australia.
Sargodon is an extinct genus of neopterygian ray-finned fish that lived during the Middle and Late Triassic epochs in what is now Europe.
Palaeoniscidae is an extinct family of "palaeoniscoid" ray-finned fishes (Actinopterygii). The family includes the genus Palaeoniscum and potentially other Palaeozoic and Mesozoic early actinopterygian genera. The name is derived from the Ancient Greek words παλαιός and ὀνίσκος.
Saurichthyiformes is an extinct order of ray-finned fish which existed in Asia, Africa, Australia, Europe and North America, during the late Permian to early Middle Jurassic. Saurichthyiiformes comprise two families, Saurichthyidae and Yelangichthyidae. Yelangichthyidae is monotypic, containing only the genus Yelangichthys. The gar or needlefish-like Saurichthyidae is primarily known from the genus Saurichthys. Additionally, the subgenera SaurorhynchusCostasaurichthys, Eosaurichthys, Lepidosaurichthys, and Sinosaurichthys are frequently used to group species, and are sometimes considered separate genera. Species are known from both marine end freshwater deposits. They had their highest diversity during the Early and Middle Triassic. Their phylogenetic position is uncertain, while they have often been considered members of Chondrostei, and thus related to living sturgeons and paddlefish, phylogenetic analysis of well-preserved remains has considered this relationship equivocal. They may actually belong to the stem-group of Actinopterygii, and thus not closely related to any living group of ray-finned fish.
Perleidiformes are an extinct order of prehistoric ray-finned fish from the Triassic period Although numerous Triassic taxa have been referred to Perleidiformes, which ones should be included for it to form a monophyletic group is a matter of ongoing scientific debate.
Dorypterus is a small, extinct genus of prehistoric ray-finned bony fish. It lived during the Wuchiapingian stage of the late Permian epoch in what is now Germany (Kupferschiefer) and England. It is a hypsisomatic bobasatraniiform with a high dorsal fin. Due to anatomical differences with other bobasatraniiforms, such as the presence of pelvic fins and the reduced scale cover, Dorypterus is placed in its own monotypic family, Dorypteridae.
Parasemionotiformes is an extinct order of neopterygian ray-finned fish that existed globally during the Triassic period. It comprises the families Parasemionotidae and Promecosominidae. Many of the included genera are monotypic and most species lived during the Early Triassic epoch.
Eigil Hans Aage Nielsen was a Danish paleontologist, who specialized in fossil vertebrate anatomy, particularly of Triassic bony fish.
