Arowanas are freshwater bony fish of the subfamily Osteoglossinae, also known as bony tongues. In this family of fish, the head is bony and the elongated body is covered by large, heavy scales, with a mosaic pattern of canals. The dorsal and anal fins have soft rays and are long based, while the pectoral and ventral fins are small. The name "bonytongues" is derived from a toothed bone on the floor of the mouth, the "tongue", equipped with teeth that bite against teeth on the roof of the mouth. The arowana is a facultative air breather and can obtain oxygen from air by sucking it into its swim bladder, which is lined with capillaries like lung tissue.
Lycoptera is an extinct genus of fish that lived from Lower Cretaceous, Barremian to Aptian in present-day China, North Korea, Mongolia and Siberia. Although there is record from Jurassic Formation in Siberia, its age remains questionable. It is known from abundant fossils representing sixteen species, which serve as important index fossil used to date geologic formations in China. Along with the genus Peipiaosteus, Lycoptera has been considered a defining member of the Jehol Biota, a prehistoric ecosystem famous for its feathered dinosaurs, which flourished for 20 million years during the Early Cretaceous, where it occurs abundantly in often monospecific beds, where they are thought to have died in seasonal mass death events. Lycoptera is a crown group teleost belonging to an early diverging lineage of the Osteoglossomorpha, which contains living mooneyes, arapaima, arowana, elephantfish and knifefish/featherbacks.
Echidnocephalus troscheli is an extinct, prehistoric halosaur. Fossils are found from Campanian strata of Westphalia, Germany. The complete and incomplete fossil specimens that have been found suggest an animal already looking very much like modern halosaurs.
Enischorhynchus is an extinct genus of prehistoric bony fish that lived during the Turonian of southern Texas.
Chongichthys is an extinct genus of prehistoric bony fish that lived during the Oxfordian stage of the Late Jurassic epoch. Fossils of the genus have been found in the Quebrada El Profeta of Chile.
Oligopleurus is an extinct genus of prehistoric bony fish that lived during the Kimmeridgian stage of the Late Jurassic epoch.
Pseudovomer minutus is an extinct species of prehistoric, Miocene carangid similar to the modern-day lookdown, Selene vomer, that lived during the Messinian subepoch of what is now Sicily.
Inichthys is an extinct genus of prehistoric marine bony fish that lived during the Lopingian epoch. Fossils were recovered in the Kuznetsk Basin, European Russia.
Opsithrissops is an extinct genus of prehistoric bony fish that lived during the Thanetian stage of the Paleocene epoch. It is a 120 centimetres (3.9 ft) fish in the family Osteoglossiformes which includes other bony-tongues such as the extant species of arowana and arapaima.
Dorsolepis is an extinct genus of prehistoric bony fish that lived during the early Anisian age in what is now France (Alsace) and Germany (Baden-Württemberg). Fossils were found in the Grès à Voltzia in Alsace and in the Buntsandstein in Baden-Württemberg.
Mioplosus is an extinct genus of percid fish that lived from the early to middle Eocene. Five species of the genus has been described, Mioplosus labracoides is found in the Green River Formation Lagerstätte. Mioplosus has numerous extant relatives in Northern Hemisphere fresh- and brackish water, as well as fossil relatives in Asia, Europe and New Zealand, and may be closely related to the modern-day pike-perches.
Acentrophorus is an extinct genus of prehistoric ray-finned fish from the Wuchiapingian of England and Germany (Kupferschiefer). There may also be a Triassic occurrence in Australia.
Coccocephalichthys is an extinct genus of prehistoric bony fish from the Carboniferous period. The type species, C. wildi, lived during the Bashkirian age of the Pennsylvanian epoch in what is now Lancashire, United Kingdom.
Xiphiorhynchus is an extinct genus of prehistoric swordfish that lived from the Eocene until the Oligocene. Unlike the modern swordfish, both the upper and lower jaws of Xiphiorhynchus were extended into blade-like points.
Sundayichthys is an extinct genus of prehistoric bony fish that lived during the Carboniferous period in what is now South Africa. Fossils were recovered from the Upper Witteberg Series.
Hemicalypterus is an extinct genus of prehistoric ray-finned fish that lived during the late Triassic period. It contains a single species, Hemicalypterus weiri. Fossils have been collected in the southwestern United States, including Utah and New Mexico. Hemicalypterus belonged to the family Dapediidae, and like other members of its family, it was a deep-bodied fish with a covering of thick ganoid scales. It differed from other dapediids in lacking scales on the posterior part of the body, and in possessing unusual, multicuspid teeth. These teeth were similar to those of modern-day herbivorous fish, which indicates that Hemicalypterus may have been a herbivore as well.
Litoptychius is an extinct genus of prehistoric bony fish.
Saurorhynchus is an extinct genus of carnivorous bony fish that lived during the Early and Middle Jurassic epochs. Fossils have been found in Europe and North America (Canada). It is commonly found in pelagic and lagoonal deposits, but mostly marine. Largest specimens can grow up to 1.9 metres (6.2 ft).
The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys. During the late Cambrian, eel-like jawless fish called the conodonts, and small mostly armoured fish known as ostracoderms, first appeared. Most jawless fish are now extinct; but the extant lampreys may approximate ancient pre-jawed fish. Lampreys belong to the Cyclostomata, which includes the extant hagfish, and this group may have split early on from other agnathans.
Ohmdenia is an extinct genus of prehistoric bony fish that lived from the Toarcian stage of the Early Jurassic period. Ohmdenia was first described in 1953 by Bernhard Hauff, based on a fossil found in the well-known Posidonia Shale in Holzmaden, Germany. For a long time this animal has been considered a close relative of Birgeria, a great predator typical of the Triassic period with an uncertain systematic position. Further studies have shown similarities with the Pachycormiformes, a group considered close to the origin of teleosts and also including giant forms and planktives. Some studies have erroneously indicated Ohmdenia as a synonym of Saurostomus, other studies have instead placed Ohmdenia as an important evolutionary passage between the basal pachicormiforms and the more derived planktivore pachicormiformes.
