| Jurassichelon Temporal range: | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Pantestudines |
| Clade: | Testudinata |
| Clade: | † Thalassochelydia |
| Genus: | † Jurassichelon Pérez García, 2015 |
| Type species | |
| Jurassichelon oleronensis | |
Jurassichelon is an extinct genus of basal eucryptodiran turtle that inhabited France during the early Tithonian stage of the Late Jurassic epoch. It is known from a single species, J. oleronensis. [1]
Machimosaurus is an extinct genus of machimosaurid crocodyliform from the Late Jurassic and Early Cretaceous. The type species, Machimosaurus hugii, was found in Switzerland. Other fossils have been found in England, France, Germany, Portugal, Switzerland and Tunisia. Machimosaurus rex is the largest named teleosauroid and thalattosuchian, with an estimated length of up to 7.15 m (23.5 ft). Machimosaurus is the largest known crocodyliform of the Jurassic.
Trionychia is a superfamily of turtles which encompasses the species that are commonly referred to as softshelled turtles as well as some others. The group contains two families, Carettochelyidae, which has only one living species, the pig-nosed turtle native to New Guinea and Northern Australia, and Trionychidae, the softshelled turtles, containing numerous species native to Asia, North America and Africa. These families likely diverged during the late Jurassic. The oldest known stem-trionychian is Sinaspideretes from the Late Jurassic of China.
Protostegidae is a family of extinct marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, Archelon, had a head one metre (39 in) long. Like most sea turtles, they had flattened bodies and flippers for front appendages; protostegids had minimal shells like leatherback turtles of modern times.
Paracryptodira is an extinct group of reptiles in the clade Testudinata, known from the Jurassic to Paleogene of North America and Europe. Initially treated as a suborder sister to Cryptodira, they were then thought to be a very primitive lineage inside the Cryptodira according to the most common use of the latter taxon. They are now often regarded as late-diverging stem-turtles, lying outside the clade formed by Cryptodira and Pleurodira. Paracryptodires are divided into three main groups, Compsemydidae, known from the Late Jurassic to Paleocene of North America and Europe, Pleurosternidae, known from the Late Jurassic to Early Cretaceous of North America and Europe, and Baenidae, known from the Early Cretaceous to Eocene of North America. The latter two groups are more closely related to each other than to Compsemys, forming the clade Baenoidea.
Sinemys is an extinct genus of turtle from the Late Jurassic to Early Cretaceous of China. Three species have been named: S. lens, the type species, from the Kimmeridgian-Tithonian of Shandong; S. gamera, from the Valanginian-Albian of Nei Mongol, and S. brevispinus from Early Cretaceous of Nei Mongol. S. wuerhoensis, from the Aptian-Albian of Xinjiang, is not referrable to this genus. Specimen that may be belong to this genus were also known from Japan, although later abstract considered it as indeterminate sinemydid. The species S. gamera is noted for the presence of a pair of elongate spines projecting outwards and backwards from seventh costal of the carapace. These may have served a hydrodynamic function.
Sinaspideretes is an extinct genus of turtle from the Late Jurassic of China, probably from the Shaximiao Formation. It is considered the earliest and most basal representative of the Trionychia, and is possibly the oldest known member of Cryptodira. In 2013, it was proposed that this animal and the genus Yehguia are in fact one and the same.
Euclastes is an extinct genus of sea turtles that survived the Cretaceous–Paleogene mass extinction. The genus was first named by Edward Drinker Cope in 1867, and contains three species. E. hutchisoni, was named in 2003 but has since been reassigned to the genus Pacifichelys, while E. coahuilaensis named in 2009 was reassigned as Mexichelys coahuilaensis in 2010.
Glyptops is an extinct genus of pleurosternid freshwater turtle known from the Late Jurassic of North America.
The Tugulu Group is a geological Group in Xinjiang, China whose strata date back to the Early Cretaceous. Dinosaur skeletal remains and footprints are among the fossils that have been recovered from the formation.
Kirgizemys is an extinct genus of turtle from Early Cretaceous of China, South Korea, Mongolia, Russia and Kyrgyzstan.
Notoemys is an extinct genus of platychelyid turtle known from the Late Jurassic and Early Cretaceous of the Americas.
Uluops is an extinct genus of paracryptodire turtle from the Late Jurassic (Tithonian) of North America. The type and only species is Uluops uluops, which is known from a single skull from the Morrison Formation.
The Early Cretaceous Phu Kradung Formation is the lowest member of the Mesozoic Khorat Group which outcrops on the Khorat Plateau in Isan, Thailand. This geological formation consists of micaceous, brown to reddish-brown siltstone beds with minor brown and grey shale and sandstone beds. Occasional lime-noduled conglomerate occurs.
Compsemys is an extinct genus of prehistoric turtles from the Late Cretaceous and Paleocene of North America and possibly Europe. The type species C. victa, first described by Joseph Leidy from the Hell Creek Formation in Montana in 1856, and another probable species C. russelli, described in 2012, from Paleocene deposits in France. Its affinites have long been uncertain, but it has recently been considered to be the most basal member of Paracryptodira, despite the clade first appearing in the Late Jurassic, and is sometimes included in its own family, Compsemydidae. A revision in 2020 found Compsemydidae to be more expansive, also containing Riodevemys and Selenemys from the Late Jurassic of Europe, and Peltochelys from the Early Cretaceous of Europe.
Hoyasemys is an extinct genus of basal eucryptodiran freshwater turtle from Lower Cretaceous deposits of Cuenca Province, Spain. It is known from the holotype MCCM-LH 84, a nearly complete and articulated skeleton including the skull. It was found in the 1980s from the Las Hoyas site of the Calizas de La Huérguina Formation, near La Cierva township, Spain. It was first named by Adán Pérez-García, Marcelo S. de la Fuente and Francisco Ortega in 2011 and the type species is Hoyasemys jimenezi. The generic name is derived from the word Hoyas meaning "the basin" in Spanish, which refers to the Las Hoyas fossil site it was found in, and emys. The specific name honors Dr. Emiliano Jiménez Fuentes.
Pleurosternidae is an extinct family of freshwater turtles belonging to Paracryptodira. They are definitively known from the Late Jurassic to Early Cretaceous (Albian) of Western Europe and North America.
Xinjiangchelyidae is an extinct family of turtles known from the Lower Jurassic to the Middle Cretaceous of Asia and western Europe. They have generally been interpreted as either being basal cryptodires or placed outside of crown Testudines.
Meiolaniformes is an extinct clade of stem-group turtles, defined as all taxa more closely related to Meiolania than to Cryptodira and Pleurodira. It is known from the Early Cretaceous to the Holocene of Australia, Oceania and South America. Some Eurasian taxa have been suggested to be part of the group, but this is disputed.
Angolachelonia is a clade of extinct turtles from the Late Jurassic to Paleogene of Eurasia. The group is defined as all taxa derived from the ancestor of the type genus Angolachelys and Solnhofia, a definition that could potentially encompass a clade of entirely marine turtles. Angolachelonia was originally inclusive of only Solnhofia, Angolachelys and Sandownia when originally conceived by Octavio Mateus and colleagues in 2009, but later phylogenetic analyses by Serjocha Evers and Roger Benson in 2018 unites the family Sandownidae, including Angolachelys and Sandownia among other taxa, with the entirely Late Jurassic clade Thalassochelydia, where Solnhofia may be a basal member. While the placement of Solnhofia is weak and the clade that Angolachelonia represents may change with further analysis, the clade of Sandownidae and Thalassochelydia is well-supported, and does not collapse despite the uncertain evolutionary history of the group. Three alternative potential origins of Angolachelonia sensu Evers and Benson are shown below.
Phunoichelys is an extinct genus of xinjiangchelyid turtle that inhabited Thailand during the Jurassic period and is known from a single species, P. thirakhupti.