The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland, the Calcaire de Caen of France, the Daohugou Beds in China, the Itat Formation in Russia, the Tiouraren Formation of Niger, and the Isalo III Formation of western Madagascar.
Pachycormus is an extinct genus of pachycormiform ray-finned fish known from the Early Jurassic of Europe. The type species P. macropterus was first named as a species of Elops by Henri Marie Ducrotay de Blainville in 1818, it was placed into the newly named genus Pachycormus by Louis Agassiz in 1833. Fossils have been found in marine deposits from France, Germany and England. Pachycormus has recently been considered monotypic, only containing P.macropterus, with other species considered junior synonyms of the former, though this has subsequently been questioned. Pachycormus has generally been considered basal among Pachycormiformes, with a recent phylogeny finding it to be the second most basal pachycormiform after Euthynotus. It grew up to 1 m (3.5 ft) in length. The teeth are short and designed for grasping. Its ecology has been interpreted as that of a generalist predator. Stomach contents indicate that its diet included cephalopods, and small fish, including juvenile Pachycormus. One particular specimen shows that it died because of swallowing an ammonite too large for its size, and the ammonite itself was only shortly digested just before the fish's death.
Bobbichthys is an extinct genus of marine ray-finned fish that lived in what is now Chile during the Oxfordian stage of the Late Jurassic epoch. It was a member of the Varasichthyidae, a family of potentially crossognathiform fish.
Domeykos is an extinct genus of ray-finned fish that lived in what is now Chile during the Oxfordian stage of the Late Jurassic epoch. It contains one species, Domeykos profetaensis.
Varasichthys is an extinct genus of ray-finned fish that lived during the Oxfordian stage of the Late Jurassic epoch. It contains one species, Varasichthys ariasi, fossils of which have been found in the Domeyko Range of Antofagasta Region, northern Chile. It has been placed in the family Varasichthyidae together with the genera Bobbichthys, Domeykos, Luisichthys and Protoclupea.
Antofagastaichthys is an extinct genus of ray-finned fish that lived in what is now Chile during the Oxfordian stage of the Late Jurassic epoch. It contains one species, A. mandibularis, which is known from several fragmentary specimens discovered in the El Profeta Formation of Antofagasta Province.
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.
Euthynotus is an extinct genus of prehistoric bony fish that lived during the early Toarcian stage of the Early Jurassic epoch. It is generally considered the basalmost pachycormiform.
Protoclupea is an extinct genus of ray-finned fish that lived from the Oxfordian to the early Tithonian stage of the Late Jurassic epoch. It contains one species, Protoclupea chilensis, fossils of which have been found in the Domeyko Range of Antofagasta Region, northern Chile. The genus has been placed in the family Varasichthyidae together with the genera Bobbichthys, Domeykos, Luisichthys and Varasichthys.
Eugnathides is an extinct genus of prehistoric bony fish that lived from the Oxfordian to the early Tithonian stage of the Late Jurassic epoch. Eugnathides may have been similar to Sphaerodontes.
Asthenocormus is an extinct genus of large marine pachycormiform ray-finned fish. It contains a single species, A. titanius. A member of the edentulous suspension feeding clade within the Pachycormiformes, fossils have been found in the Upper Jurassic plattenkalks of Bavaria, Germany.
Eurycormus is an extinct genus of prehistoric bony fish that lived from the Callovian stage of the Middle Jurassic epoch to the early Tithonian stage of the Late Jurassic epoch.
Swenzia is an extinct genus of coelacanthid fish from the late Jurassic of France. It contains a single species, S. latimerae, which was originally described as Wenzia latimerae. Because the generic name Wenzia was already preoccupied by a snail, the generic name was amended to Swenzia. It is the fossil genus most closely related to the living coelacanth, Latimeria.
Trachymetopon is an extinct genus of prehistoric coelacanth from the Jurassic of Europe. Fossils have been found in the Early Jurassic Posidonia Shale of Germany the Middle Jurassic Marnes de Dives of France, and probably the Late Jurassic Kimmeridge Clay of England. Only one species has been named, Trachymetopon liassicum, described by Henning in 1951 from an almost complete specimen found in the Lower Toarcian of Ohmden in Baden-Württemberg. Another specimen is known from the same site, and two older specimens come from the Sinemurian of Holzmaden. The holotype of this species is 1.6 metres in length. A giant specimen of an undetermined species of Trachymetopon found at the Middle Jurassic Falaises des Vaches Noires of Normandy. This specimen, composed of a 53 cm long palatoquadrate, belongs to an individual 4 metres (13 ft) in length. A basisphenoid found in a museum in Switzerland that likely originates from the same locaity probably belonged to an individual around 5 m (16 ft) long, making Trachymetopon the largest of all coelacanths alongside Mawsonia. A study published in 2015 revealed that this coelacanth belongs to the Mawsoniidae. Trachymetopon is one of the few known mawsoniids to have been exclusively marine, while most of the other members of the group have lived in fresh and brackish waters.
Ascalabos is an extinct genus of marine ray-finned fish known from the Late Jurassic Solnhofen Limestone of Germany. It contains one species, A. voithii. Some authorities synonymize it with Leptolepis.
Proleptolepis is an extinct genus of ray-finned fish belonging to the family Leptolepidae.
Proscinetes is an extinct genus of prehistoric pycnodontiform ray-finned fish from the Jurassic.
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).
Peipiaosteus is an extinct genus of prehistoric chondrostean ray-finned fish. Its fossils are found in the Early Cretaceous Jiufotang Formation, Pani Lake, Liaoning Province, China.
Crossognathiformes is an extinct order of ray-finned fish that lived from the Late Jurassic to the Eocene. Its phylogenetic placement is disputed; some authors have recovered it as part of the teleost stem group, while others place it in a basal position within crown group Teleostei. Other placements have found it to be paraphyletic, with the Varasichthyidae being stem-group teleosts whereas the other, "true" crossognathiforms are crown-group teleosts within the Teleocephala.
