The Jurassic is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era as well as the eighth period of the Phanerozoic Eon and is named after the Jura Mountains, where limestone strata from the period were first identified.
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.
Chimaeras are cartilaginous fish in the order Chimaeriformes, known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively.
Caturus is an extinct genus of predatory marine fishes in the family Caturidae in the order Amiiformes, related to modern bowfin. It has been suggested that the genus is non-monophyletic with respect to other caturid genera.
Lepidotes is an extinct genus of Mesozoic ray-finned fish. It has long been considered a wastebasket taxon, characterised by "general features, such as thick rhomboid scales and, for most of the species, by semi-tritorial or strongly tritorial dentition". with dozens of species assigned to it. Fossils attributed to Lepidotes have been found in Jurassic and Cretaceous rocks worldwide. It has been argued that Lepidotes should be restricted to species closely related to the type species L. gigas, which are only known from the Early Jurassic of Western and Central Europe, with most other species being not closely related, with other species transferred to new genera such as Scheenstia.Lepidotes belongs to Ginglymodi, a clade of fish whose only living representatives are the gars (Lepisosteidae). The type species L. gigas and close relatives are thought to be members of the family Lepidotidae, part of the order Lepisosteiformes within Ginglymodi, with other species occupying various other positions within Ginglymodi.
Pycnodus is an extinct genus of ray-finned fish from the Eocene period. It is wastebasket taxon, although many fossils from Jurassic or Cretaceous are assigned to this genus, only Eocene species, P. apodus is valid. As its name suggests, it is the type genus of Pycnodontiformes.
Aspidorhynchus is an extinct genus of predatory ray-finned fish from the Middle Jurassic to the earliest Cretaceous. Fossils have been found in Europe, Antarctica and the Caribbean.
Thrissops is an extinct genus of stem-teleost fish from the Jurassic period. Its fossils are known from the Solnhofen Limestone, as well as the Kimmeridge Clay.
Homoeosaurus is an extinct genus of rhynchocephalian reptile, known from the Late Jurassic-earliest Cretaceous of Europe, with specimens being reported from France, England and Germany. Several species have been described within the genus, based on varying proportions of the limb bones to the body length based on the presacral vertebrae. Specimen C.M.6438 of H. maximiliani from Germany has a total length of around 17 centimetres (6.7 in), with a skull length of about 1.7 centimetres (0.67 in). In comparison to other rhynchocephalians, the limbs are proportionally long. Recent studies have classified Homoeosaurus as a member of Neosphenodontia, with some studies including it as part of the clade Leptorhynchia, also including sapheosaurs, pleurosaurs, Kallimodon and Vadasaurus. Despite being found in aquatic deposits, it is suggested to have been terrestrial. It is thought to have been a carnivore/insectivore. One specimen was found as stomach contents of the fish Belonostomus.
Ichthyodectiformes is an extinct order of marine stem-teleost ray-finned fish. The order is named after the genus Ichthyodectes, established by Edward Drinker Cope in 1870. Ichthyodectiforms are usually considered to be some of the closest relatives of the teleost crown group.
Belonostomus is a genus of prehistoric ray-finned fish that was described by Louis Agassiz in 1844. It is a member of the order Aspidorhynchiformes, a group of fish known for their distinctive elongated rostrums.
Pachythrissops is an extinct genus of ray-finned fish. It contains two species, P. laevis from the Purbeckian of England and P. propterus from the Tithonian of Germany. A third species, P. vectensis, has been reassigned to the elopiform genus Arratiaelops. Pachythrissops is often regarded as one of the most primitive members of the order Ichthyodectiformes; however, a phylogenetic analysis by Cavin et al. (2013) placed it and the related genus Ascalabothrissops outside the group.
Pachycormus is an extinct genus of pachycormiform ray-finned fish known from the Early Jurassic of Europe.
Arganodus is an extinct genus of freshwater lungfish that had a wide global distribution throughout much of the Triassic period, with a single species surviving across Gondwana into the Cretaceous. It is the only member of the family Arganodontidae, although it is sometimes placed in the Ceratodontidae or synonymized with the genus Asiatoceratodus.
Ainia is an extinct genus of prehistoric ray-finned fish that lived during the Kimmeridgian stage of the Late Jurassic epoch. It contains a single species, A. armata, known from the famous Solnhofen Limestone of Germany. It is a distant relative of the bowfin, although it is more closely related to genera such as Caturus and Osteorachis.
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.
Occithrissops is an extinct genus of ray-finned fish of the Jurassic, described from Sundance Formation. The genus name of Occithrissops refers to the occidental occurrence of the genus and its relationship to Thrissops.
The Solnhofen Limestone or Solnhofen Plattenkalk is a collective term for multiple Late Jurassic lithographic limestones in southeastern Germany, which is famous for its well preserved fossil flora and fauna dating to the late Jurassic (Kimmeridgian-Tithonian). The paleoenvironment is also often referred to as the Solnhofen Archipelago. The Solnhofen Archipelago was located at the northern edge of the Tethys Ocean as part of a shallow epicontinental sea and is firmly a part of the Mediterranean realm.
Teleosteomorpha is a clade of ray-finned fishes containing all teleost fish and their closest extinct relatives. Also in this group are two diverse Mesozoic fish orders, the Aspidorhynchiformes and the Pachycormiformes. Several other non-teleostomorph teleosteans existed throughout the Mesozoic, although not as dominant as the two main clades in the group.
Coccolepididae is an extinct family of ray-finned fish, known from the Early Jurassic to Early Cretaceous, most of which were originally referred to the type genus Coccolepis. They had a widespread distribution, being found in North and South America, Australia, Asia and Europe. They are mostly known from freshwater environments, though several species have been found in marine environments. They are morphologically conservative, and have poorly ossified endo and exoskeletons, which usually results in poor preservation. This makes it difficult to distinguish species. They are generally small fish, with the largest known specimens reaching a length of 210 mm. Historically, they have been classified as members of “Palaeonisciformes”, a paraphyletic grouping of non-neopterygian fish, due to their plesiomorphic conservative morphology closely resembling those of many other groups of primitive fish. Some recent authors have suggested that they may belong to the order Chondrostei as relatives of the Acipenseriformes.
