Oxford Clay

Liopleurodon (; meaning 'smooth-sided teeth') is an extinct genus of carnivorous pliosaurid plesiosaurs that lived from the Callovian stage of the Middle Jurassic to the Kimmeridgian stage of the Late Jurassic period (approximately 166 to 155 million years ago). The type species is L. ferox, which is probably the only valid species. Some studies also include the second species L. pachydeirus, but this latter is considered as a probable junior synonym of L. ferox due to its lack of viable diagnosis. Fossils attributed to Liopleurodon, including some skeletons, are mainly known from Europe, with

Eustreptospondylus ( ;), from (Ancient Greek εὖ (eû), meaning "well", στρεπτός (streptós), meaning "twisted", and σπόνδυλος (spóndulos), meaning "vertebra"), is an extinct genus of megalosaurid theropod dinosaur, from the Callovian and Oxfordian stages of the Jurassic period (some time between 166 and 154 million years ago) in southern England, at a time when Europe was a series of scattered islands (due to tectonic movement at the time which raised the sea-bed and flooded the lowland).

Cryptoclidus ( ) is a genus of plesiosaur reptile from the Middle Jurassic period of England, France, and Cuba.

Peloneustes (meaning ) 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 this genus, 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

Lexovisaurus is a genus of stegosaurian dinosaur known from limb bones and armor fragments from Middle to Late Jurassic-aged strata of Europe.

Muraenosaurus (from the Latin "Muraena" meaning "eel" and "Sauros" meaning lizard) is an extinct genus of cryptoclidid plesiosaur reptile from the Oxford Clay of Southern England. The genus was given its name due to the eel-like appearance of the long neck and small head. Muraenosaurus grew up to in length and lived roughly between 160 Ma (million years ago) and 164 Ma in the Callovian of the middle Jurassic. Charles E. Leeds collected the first Muraenosaurus which was then described by H. G. Seeley. The specimen may have suffered some damage due to the casual style of Charles Leeds’ collectio

Simolestes (meaning "snub-nosed thief") is an extinct pliosaurid genus that lived in the Middle to Late Jurassic. The type specimen, NHMUK PV R 3319 is an almost complete but crushed skeleton diagnostic to Simolestes vorax, dating back to the Callovian of the Oxford Clay formation, England. The genus might also be known from the Tithonian Bhuj Formation of India (S. indicus), but the referral of this species to Simolestes is dubious. S. keileni from France was moved to the new genus Lorrainosaurus in 2023.

Cetiosauriscus ( ) is a genus of sauropod dinosaur that lived between 166 and 164 million years ago during the Callovian (Middle Jurassic Period) in what is now England. A herbivore, Cetiosauriscus had – by sauropod standards – a moderately long tail, and longer forelimbs, making them as long as its hindlimbs. It has been estimated as about long and between in weight.

Callovosaurus (meaning "Callovian lizard") 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.

Sarcolestes (from Ancient Greek σάρξ (sárx), meaning "flesh", and λῃστής (lēistḗs), meaning "robber", and thus, "flesh robber") is an extinct genus of ankylosaurian ornithischian dinosaur from the Oxford Clay of England. The current type and only species is S. leedsi, and the holotype is a single partial left mandible. The genus and species were named in 1893 by Richard Lydekker, who thought they belonged to a theropod.

Steneosaurus (from , 'narrow' and , 'lizard') is a dubious genus of teleosaurid crocodyliform from the Middle or Late Jurassic (Callovian or early Oxfordian) of France and possibly also India. The genus has been used as a wastebasket taxon for thalattosuchian fossils for over two centuries, and almost all known historical species of teleosauroid have been included within it at one point. The genus has remained a wastebasket, with numerous species still included under the label '''Steneosaurus''', many of which are unrelated to each other (either paraphyletic or polyphyletic with respect to eac

Loricatosaurus (meaning "armored lizard") is a genus of stegosaurid dinosaur known from Callovian-aged (Middle Jurassic) rocks of England and France.

Tricleidus is an extinct genus of cryptoclidid plesiosaur known from only specimen (BMNH R3539) from the middle Jurassic of United Kingdom. It was first named by Andrews in 1909 and the type species is Tricleidus seeleyi. left|thumb|Skeletal diagram

Marmornectes is a genus of pliosaurid known from the Middle Jurassic of Bedfordshire, United Kingdom.

Pachycostasaurus (meaning 'thick-ribbed lizard') is an extinct Pliosauroid from the Oxford Clay formation of Peterborough, England.

Tyrannoneustes is an extinct genus of geosaurine metriorhynchid crocodyliform from the Callovian stage Oxford Clay Formation of England and the Marnes de Dives of France. It contains a single species, Tyrannoneustes lythrodectikos, meaning "blood-biting tyrant swimmer".

Suchodus is an extinct genus of metriorhynchid thalattosuchian from the Middle to Late Jurassic period of England and France It measured between in total body length.'''' It was a fully marine reptile that would have fed on other large marine fauna.

left|thumb|Holotype of G. leedsi, NHMUK PV R3540 thumb Gracilineustes is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Gracilineustes was a carnivore that spent much, if not all, its life out at sea. It was a small reptile, with G. leedsi measuring long and G. acutus measuring long. thumb|Skull and limb of G. leedsi ==Discovery and species== Fossil specimens referrable to Gracilineustes are known from Middle-Late Jurassic deposits of England and France.

Eardasaurus is a genus of thalassophonean pliosaurid from the middle Jurassic Oxford Clay Formation. The animal would have measured over long (the tail was not fully preserved) and possessed a high amount of teeth relative to other pliosaurs. Its teeth show distinct ridges formed by the tooth enamel, some of which are very pronounced and similar to carinae, giving the teeth a cutting edge.

Isanichthys is an extinct genus of freshwater lepidotid ginglymodian fish from the Late Jurassic and Early Cretaceous. Four species are known from Thailand, China and the United Kingdom, two of which were previously classified in genera.