Choristodera is an extinct order of semiaquatic diapsid reptiles that ranged from the Middle Jurassic, or possibly Triassic, to the late 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. Cladists have placed choristoderes as neodiapsids, but the exact phylogenetic position of Choristodera is still uncertain.
Psittacosaurus is a genus of extinct ceratopsian dinosaur from the Early Cretaceous of what is now Asia, existing between 126 and 101 million years ago. It is notable for being the most species-rich non-avian dinosaur genus. Up to 12 species are known, from across China, Mongolia, Siberia, and possibly Thailand. The species of Psittacosaurus were obligate bipeds at adulthood, with a high skull and a robust beak. One individual was found preserved with long filaments on the tail, similar to those of Tianyulong. Psittacosaurus probably had complex behaviours, based on the proportions and relative size of the brain. It may have been active for short periods of time during the day and night, and had well-developed senses of smell and vision.
Hyphalosaurus is a genus of freshwater aquatic reptiles, belonging to the extinct order Choristodera. They lived during the early Cretaceous period, about 122 million years ago. The genus contains two species, H. lingyuanensis and H. baitaigouensis, both from the Yixian 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.
Sapeornis is a monotypic genus of avialan which lived during the early Cretaceous period. Sapeornis contains only one species, Sapeornis chaoyangensis.
Liaoxipterus is a genus of pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The type species is Liaoxipterus brachyognathus. The genus name is derived from the discovery locality Liaoxi and a Latinised Greek pteron, "wing". The specific name is derived from Greek brachys, "short" and gnathos, "jaw".
Shokawa is an extinct genus of choristoderan diapsid reptile, known from the Lower Cretaceous of Japan. It is only known from one species, Shokawa ikoi. The only known remains are a postcranial specimen lacking the skull, discovered at the KO2 locality in sediments belonging to the Okurodani Formation near the village of Shokawa in Gifu Prefecture. Shokawa possessed a long neck with at least 16 cervical vertebrae, and closely resembles and is closely related to the smaller choristoderan, Hyphalosaurus. The generic name refers to the village near where it was found, while the specific name honors the collector of the first specimen, one Mr. Ikoi Shibata.
The Jehol Biota includes all the living organisms – the ecosystem – of northeastern China between 133 and 120 million years ago. This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation and Jiufotang Formation. These deposits are composed of layers of tephra and sediment. It is also believed to have left fossils in the Sinuiju series of North Korea. The ecosystem in the Lower Cretaceous was dominated by wetlands and numerous lakes. Rainfall was seasonal, alternating between semiarid and mesic conditions. The climate was temperate. The Jehol ecosystem was interrupted periodically by ash eruptions from volcanoes to the west. The word "Jehol" is a historical transcription of the former Rehe Province.
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 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; the skull of L. inexpectatus was only about 4.53 centimeters long (1.78 in), with the total preserved body and tail length 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.
Hongshanopterus is a genus of pterodactyloid pterosaur from the Lower Cretaceous Jiufotang Formation of Liaoning, China.
Similicaudipteryx, meaning "similar to Caudipteryx", is a genus of theropod dinosaur of the family Caudipteridae.
Cteniogenys is a genus of choristodere, a morphologically diverse group of aquatic reptiles. It is part of the monotypic family Cteniogenidae. The type and only named species, C. antiquus, was named in 1928 by Charles W. Gilmore. The holotype, VP.001088, was collected in the Morrison Formation, Wyoming in 1881 by William H. Reed. More specimens have been discovered since then, including specimens from the Late Jurassic of Portugal and Middle Jurassic of Britain, which have not been assigned to species.
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.
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.
Kielanobaatar is an extinct genus of albionbaatarid multituberculate which existed in Shahai and Fuxin formations, northeastern China, during the early Cretaceous. It was first named by Nao Kusuhashi, Yaoming Hu, Yuanqing Wang, Takeshi Setoguchi and Hiroshige Marsuoka in 2010 and the type species is Kielanobaatar badaohaoensis, named after Dr. Zofia Kielan-Jaworowska, a leading specialist on Mesozoic mammals. It is known from a small fragment of the left lower jaw, including the third and fourth premolars, as well as two upper premolars. Kielanobaatar is the first record of an Asian albionbaatarid multituberculate. Since the albionbaataridae is known primarily from Europe, this discovery supports the idea of faunal exchange of terrestrial vertebrates between Europe and Asia in the Early Cretaceous.
Parahongshanornis is an extinct genus of early bird from the lower Cretaceous of what is now Liaoning Province, north-eastern China.
Ikrandraco is a genus of lonchodraconid pterodactyloid pterosaur known from Lower Cretaceous rocks in northeastern China and the Cambridge Greensand of the UK. It is notable for its unusual skull, which features a crest on the lower jaw.
Sinemydidae is an extinct family of turtles from Cretaceous to Paleocene deposits in Asia and North America. Their exact position is engimatic, they have alternatively been considered stem-group cryptodires, but also "crownward stem-turtles" alongside Macrobaenidae, Paracryptodira, Xinjiangchelyidae, Thalassochelydia and Sandownidae outside of crown Testudines.
Juehuaornis is an extinct genus of ornithuromorph bird from the Early Cretaceous of present-day China. It contains a single species, J. zhangi.
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.
