Champsosaurus is an extinct genus of crocodile-like choristodere reptile, known from the Late Cretaceous and early Paleogene periods of North America and Europe (Campanian–Paleocene). The name Champsosaurus is thought to come from champsai, (χαμψαι) said in an Ancient Greek source to be an Egyptian word for "crocodiles", and sauros, (σαύρος) Greek for "lizard". The morphology of Champsosaurus resembles that of gharials, with a long, elongated snout. It was native to freshwater environments where it likely preyed on fish, similar to living gharials.
Choristodera is an extinct order of semiaquatic diapsid reptiles that ranged from the Middle Jurassic, or possibly Triassic, to the Miocene. Choristoderes are morphologically diverse, with the best known members being the crocodile-like neochoristoderes such as Champsosaurus. Other choristoderans had lizard-like or long necked morphologies. Choristoderes appear to have been confined to the Northern Hemisphere, having been found in North America, Asia, and Europe, and possibly also North Africa. Choristoderes are generally thought to be derived neodiapsids that are close relatives or members of Sauria.
Simoedosaurus is an extinct reptile known from the Paleocene of North America, Europe and western Asia, and a member of the Choristodera, a group of aquatic reptiles that lived in the Northern Hemisphere from the Jurassic to the early Cenozoic.
Hyphalosaurus is a genus of freshwater aquatic reptiles, belonging to the extinct order Choristodera. They lived during the early Cretaceous period, about 123-120 million years ago. The genus contains two species, H. lingyuanensis from the Yixian Formation and H. baitaigouensis from both the Yixian and Jiufotang Formation of Liaoning Province, China. They are among the best-known animals from the Jehol Biota, with thousands of fossil specimens representing all growth stages in scientific and private collections.
Nuthetes is the name given to a genus of theropod dinosaur, likely a dromaeosaurid, known only from fossil teeth and jaw fragments found in rocks of the middle Berriasian age in the Cherty Freshwater Member of the Lulworth Formation in England and also the Angeac-Charente bonebed in France. If it was a dromaeosaurid, Nuthetes would have been a small predator.
Turiasauria is an unranked clade of basal sauropod dinosaurs known from Middle Jurassic to Early Cretaceous deposits in Europe, North America, and Africa.
Pachystropheus is a genus of prehistoric reptile, from the Rhaetian of southwestern England. It was named by Erika von Huene in 1935; Huene described Pachystropheus as a choristodere, but this was overlooked for decades until its redescription by Storrs and Gower in 1993. This reevaluation would extend the fossil record of choristoderes back 45 million years. However, other authors consider attribution of Pachystropheus to Choristodera problematic, stating that it depends on vertebral and girdle characters that are also found in the skeletons of aquatic reptiles other than choristoderes; most of the diagnostic features of choristoderes are skull features, but the presence of these cannot be confirmed in Pachystropheus, as there is no confirmed skull material for this taxon. Silvio Renesto (2005) found similarities in the postcranial skeleton of Pachystropheus and the thalattosaur genus Endennasaurus; according to Renesto, these similarities may indicate that Pachystropheus and Endennasaurus are close relatives, but they might as well simply be a case of a convergent evolution triggered by the aquatic lifestyle of both taxa. The placement as a thalattosaur has been supported by other researchers.
Lazarussuchus is an extinct genus of amphibious reptile, known from the Cenozoic of Europe. It is the youngest known member of Choristodera, an extinct order of aquatic reptiles that first appeared in the Middle Jurassic. Fossils have been found in Late Paleocene, Late Oligocene, Early Miocene and possibly Late Miocene deposits in France, Germany, and the Czech Republic. Two species have been named: the type species L. inexpectatus ("unexpected") from the late Oligocene of France. and L. dvoraki from the early Miocene of the Czech Republic. It was not a large animal; with the total preserved body and tail length of L. inexpectatus being just over 30 centimetres. A complete specimen of Lazarussuchus with preserved soft tissue was found from the Late Paleocene of France, but has not been assigned to a species.
Opisthias is a genus of sphenodont reptile. The type species, Opisthias rarus, is known from the Late Jurassic (Kimmeridgian-Tithonian) of western North America.
Paramacellodus is an extinct genus of scincomorph lizards from the Early Cretaceous of England and France, and the Late Jurassic of Portugal and the western United States. The type species, Paramacellodus oweni, was named in 1967 from the earliest Cretaceous (Berriasian) Purbeck Group in Dorset, England. Additional material referable to a species of Paramacellodus, possibly P. oweni, has been described from the Morrison Formation, specifically in Como Bluff, Wyoming, and Dinosaur National Monument, Utah. An indeterminate species is known from the Berriasian aged Angeac-Charente bonebed in France. Paramacellodus belongs to an extinct family of scincomorphs called Paramacellodidae, which spanned most of Laurasia during the Late Jurassic and Early Cretaceous and represented one of the earliest evolutionary radiations of lizards.
Dorsetisaurus is a genus of extinct lizard, known from the Late Jurassic of North America, and the Late Jurassic-earliest Cretaceous of Europe. The genus was first reported from the Early Cretaceous (Berriasian) Lulworth Formation of the Purbeck Group of Durlston Bay, in Dorset. It has also been reported from the Late Jurassic aged Alcobaça Formation of Portugal, the Aptian-Albian Dzunbain Formation of Mongolia, and the Morrison Formation of Western North America present in stratigraphic zones 2, 4, and 5. It is considered the oldest widely accepted member of Anguimorpha. based on the presence of 11 shared synapomorphies.
Parviraptor is a genus of squamate containing one species, Parviraptor estesi, from the Late Jurassic (Tithonian) or Early Cretaceous (Berriasian) Purbeck Limestone Formation of Dorset, England. A second species, Parviraptor gilmorei, was described from the Late Jurassic Morrison Formation of Western North America; it was present in stratigraphic zone 4. However, the second species was subsequently transferred to a separate genus Diablophis. An indeterminate species is known from the Bathonian aged Kirtlington Mammal Bed.
The Kuwajima Formation is an Early Cretaceous geologic formation in Japan. Its precise age is uncertain due to a lack of identifying fossils, and it was previously considered likely Valanginian to Hauterivian in age. However, it is now considered to probably be Barremian in age. Dinosaurs and other vertebrates has been recovered from the Kaseki-kabe "Fossil-bluff" locality in the uppermost part of the formation.
Monjurosuchus is a genus of choristoderan reptile that lived in what is now China and Japan during the Early Cretaceous. It has large eyes, a rounded skull, robust legs with short claws, and a long, thin tail. Fossils have been found that preserve soft tissue, showing that it had soft skin and webbed feet.
Khurendukhosaurus is a genus of choristodere, a type of amphibious reptile. It is known from Lower Cretaceous rocks of Mongolia and Russia. Two species have been named. The type species, K. orlovi, was named in 1984 by Sigogneau–Russell and Efimov for the fragmentary postcranial skeleton PIN 3386/3. This specimen was discovered in the Albian-age Lower Cretaceous Khuren Dukh Formation Formation at Hüren Dukh, central Mongolia. The lake deposits at this site also contain fossils of the choristoderes Irenosaurus and Tchoiria. Other postcranial bones of K. orlovi have been found at this site as well.
Tchoiria () is a genus of neochoristoderan reptile from the Early Cretaceous of Mongolia. The name Tchoiria comes from the city of Choir which is nearby to where the holotype was found. Tchoiria is thought to have a similar diet to another neochoristoderan reptile, Champsosaurus, due to morphology of the skull. It would hunt in freshwater environments, like the living gharials, where it would prey on many different types of fish and turtles.
Neochoristodera is a lineage of specialised crocodile-like fully aquatic choristodere reptiles. Noted for their long jaws and large size, these animals were predominant across the Northern Hemisphere, occurring in freshwater and coastal environments across the Cretaceous and early Cenozoic.
Philydrosaurus is an extinct genus of choristoderan which existed in China during the Early Cretaceous. The type species P. proseilus was named in 2005. Philydrosaurus was found from the Jiufotang Formation and is slightly younger than Monjurosuchus, which was found from the Yixian Formation.
Coeruleodraco is an extinct genus of choristoderan known from the Late Jurassic (Oxfordian) Tiaojishan Formation in China. Coeruleodraco is significant as the most complete Jurassic choristodere taxon, as the only other named Jurassic choristodere Cteniogenys is based on fragmentary remains. Although similar to Philydrosaurus in its proportions and postcranial characters, it is distinct in retaining several apparently plesiomorphic characters, including a short snout, paired external nares and an open lower temporal fenestra.
Heishanosaurus is an extinct genus of choristodere reptile from the Early Cretaceous of China. The type and currently only known species is Heishanosaurus pygmaeus. It is unusual as it is much more primitive than other known choristoderes from the Early Cretaceous of Asia, and retains many plesiomorphic characters.
