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 and is named after the Jura Mountains, where limestone strata from the period were first identified.
Liopleurodon is an extinct genus of carnivorous pliosaurs that lived from the Callovian stage of the Middle Jurassic to the Kimmeridgian stage of the Late Jurassic period. The taxonomic history of the animal is quite complex. The type species L. ferox, which is probably the only valid species, was erected in 1873 by Henri Émile Sauvage from a single tooth discovered near the French commune of Boulogne-sur-Mer, in Pas-de-Calais. Rather, in 1869 Harry Govier Seeley erected a species of Pliosaurus, Pliosaurus pachydeirus, based on a series of cervical vertebrae that had been discovered near the civil parish of Great Gransden, Cambridgeshire, England. In 1960, Lambert Beverly Tarlo moved this species within the genus Liopleurodon. However, its validity as a distinct species has been questioned since the beginning of the 21st century, in particular because its supposed distinctive characteristics would be in fact individual variations, suggesting that it is a probable junior synonym of L .ferox. However, identification of a neotype specimen of L. ferox is necessary to confirm whether this observation is true. Numerous fossil specimens attributed to Liopleurodon, even including numerous skeletons, have been discovered in Europe, Russia and Mexico. Other additional species were even proposed, but these are currently seen as coming from other pliosaurid genera.
The Oxford Clay is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay Formation dates to the Jurassic, specifically, the Callovian and Oxfordian ages, and comprises two main facies. The lower facies comprises the Peterborough Member, a fossiliferous organic-rich mudstone. This facies and its rocks are commonly known as lower Oxford Clay. The upper facies comprises the middle Oxford Clay, the Stewartby Member, and the upper Oxford Clay, the Weymouth Member. The upper facies is a fossil poor assemblage of calcareous mudstones.
Callovosaurus is a genus of iguanodontian dinosaur known from most of a left thigh bone discovered in Middle Jurassic-age rocks of England. At times, it has been considered dubious or a valid genus of basal iguanodontian, perhaps a dryosaurid.
Hybodus is an extinct genus of hybodont that lived from the Middle Triassic to the Late Cretaceous periods. Species closely related to the type species Hybodus reticulatus lived during the Early Jurassic epoch. Numerous species have been assigned to Hybodus spanning a large period of time, and it is currently considered a wastebasket taxon that is 'broadly polyphyletic' and requires reexamination.
Bittacidae is a family of scorpionflies commonly called hangingflies or hanging scorpionflies.
Anaxyelidae is a family of incense cedar wood wasps in the order Hymenoptera. It contains only one living genus, Syntexis, which has only a single species, native to Western North America. Fossils of the family extend back to the Middle Jurassic, belonging to over a dozen extinct genera, with a particularly high diversity during the Early Cretaceous. Syntexis lay eggs in the sapwood of conifers, preferring recently burnt wood.
Peloneustes is a genus of pliosaurid plesiosaur from the Middle Jurassic of England. Its remains are known from the Peterborough Member of the Oxford Clay Formation, which is Callovian in age. It was originally described as a species of Plesiosaurus by palaeontologist Harry Govier Seeley in 1869, before being given its own genus by naturalist Richard Lydekker in 1889. While many species have been assigned to Peloneustes, P. philarchus is currently the only one still considered valid, with the others moved to different genera, considered nomina dubia, or synonymised with P. philarchus. Some of the material formerly assigned to P. evansi have since been reassigned to "Pliosaurus" andrewsi. Peloneustes is known from many specimens, including some very complete material.
Hybodontiformes, commonly called hybodonts, are an extinct group of shark-like cartilaginous fish (chondrichthyans) which existed from the late Devonian to the Late Cretaceous. Hybodonts share a close common ancestry with modern sharks and rays (Neoselachii) as part of the clade Euselachii. They are distinguished from other chondrichthyans by their distinctive fin spines and cephalic spines present on the heads of males. An ecologically diverse group, they were abundant in marine and freshwater environments during the late Paleozoic and early Mesozoic, but were rare in open marine environments by the end of the Jurassic, having been largely replaced by modern sharks, though they were still common in freshwater and marginal marine habitats. They survived until the end of the Cretaceous, before going extinct.
The Taynton Limestone is a geological formation in Oxfordshire in the United Kingdom. It dates to the Middle Jurassic, mid-Bathonian stage. It predominantly consists of ooidal grainstone. The term "Stonesfield Slate" refers to slaty limestone horizons within the formation that during the 18th and 19th centuries were extensively quarried for use in roof tiling within the vicinity of Stonesfield, Oxfordshire. Previously these were thought to belong to the Sharp's Hill Formation, but boreholes and shaft sections suggest that at least three horizons within the Taynton Limestone were quarried for the slate. These horizons are well known for producing a diverse set of fossils including those of plants, insects as well as vertebrates, including some of the earliest known mammals, pterosaurs as well as those of first dinosaur ever described, Megalosaurus.
The Matmor Formation is a geologic formation of up to 100 metres (330 ft) thick, that is exposed in Hamakhtesh Hagadol in southern Israel. The Matmor Formation contains fossils from a Jurassic equatorial shallow marine environment. Bivalves, gastropods, sponges, corals, echinoderms, and sclerobionts are present in the Matmor Formation to various degrees. The stratigraphy of the Matmor Formation consists of alternating layers of limestone and marl.
The Haifanggou Formation, also known as the Jiulongshan Formation, is a fossil-bearing rock deposit located near Daohugou village of Ningcheng County, in Inner Mongolia, northeastern China.
Ithonidae, commonly called moth lacewings and giant lacewings, is a small family of winged insects of the insect order Neuroptera. The family contains a total of ten living genera, and over a dozen extinct genera described from fossils. The modern Ithonids have a notably disjunct distribution, while the extinct genera had a more global range. The family is considered one of the most primitive living neuropteran families. The family has been expanded twice, first to include the genus Rapisma, formerly placed in the monotypic family Rapismatidae, and then in 2010 to include the genera that had been placed into the family Polystoechotidae. Both Rapismatidae and Polystoechotidae have been shown to nest into Ithonidae sensu lato. The larvae of ithonids are grub-like, subterranean and likely phytophagous.
Orthacodontidae is an extinct family of sharks. It is disputed as to whether it belongs to the modern shark order Hexanchiformes, or the extinct order Synechodontiformes. It contains two genera. Some other authors included it in Lamniformes.
Synechodontiformes is an extinct order of prehistoric shark-like cartilaginous fish, known from the Permian to the Paleogene. They are considered to be members of Neoselachii, the group that contains modern sharks and rays.
Archisargidae is an extinct family of brachyceran flies known from the Jurassic and Cretaceous periods. It is part of the extinct superfamily Archisargoidea. Most members of the family are known from the Callovian-Oxfordian Daohugou biota of Inner Mongolia, China, and the equivalently aged Karabastau Formation of Kazakhstan. The family has been found to be paraphyletic with respect to Eremochaetidae in a cladistic analysis.
Egertonodus is an extinct genus of shark-like hybodont fish. It includes E. basanus from the Jurassic of Europe and North Africa and Cretaceous of North America, North Africa and Europe, and E. duffini from the Middle Jurassic of England. Indeterminate remains of the genus have been reported from the Early Cretaceous of Asia. E. basanus is known from preserved skull material, while E. duffini is only known from teeth. The genus is distinguished from Hybodussensu stricto by characters of the skull and teeth. E. basanus, the most common species, is thought to have reached 1.5 m in length. E. fraasi from the Late Jurassic of Germany, known from a poorly preserved full body fossil, was placed in Egertonodus in one study, but this has been subsequently questioned by other authors, due to strong differences in tooth morphology from the type species. Fossils have been found in freshwater and lagoonal environments.
"Pliosaurus" andrewsi is an extinct species of pliosaurid plesiosaurs that lived during the Callovian stage of the Middle Jurassic, in what is now England. The only known fossils of this taxon were discovered in the Peterborough Member of the Oxford Clay Formation. Other attributed specimens have been discovered in various corners of Eurasia, but these are currently seen as indeterminate or coming from other taxa. The taxonomic history of this animal is quite complex, because several of its fossils were attributed to different genera of pliosaurids, before being concretely named and described in 1960 by Lambert Beverly Tarlo as a species of Pliosaurus. However, although the taxon was found to be valid, subsequent revisions found that it is not part of this genus, and therefore a taxonomic revision must be carried out on this species.
Planohybodus is an extinct genus of hybodont, known from the Middle Jurassic-Early Cretaceous (Bathonian-Barremian) of Europe and the Indian subcontinent. Fossils have been found in marine as well as freshwater environments. The genus contains 3 confirmed species, two of which were originally assigned to the genus Hybodus. Possible records have been reported from the Late Jurassic of Mexico, the Early Cretaceous of Brazil and the Late Cretaceous (Santonian) of North America, but these are unconfirmed. Planohybodus peterboroughensis is suggested to have reached lengths of 2–3 metres (6.6–9.8 ft). A specimen of the ammonite genus Orthaspidoceras from the Late Jurassic of France has been found with an embedded tooth of Planohybodus, suggesting that while the teeth of Planohybodus were adapted to tearing soft bodied prey, it would attack hard-shelled prey at least on occasion.
