| Eopolycotylus Temporal range: | |
|---|---|
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| Life restoration | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Superorder: | † Sauropterygia |
| Order: | † Plesiosauria |
| Family: | † Polycotylidae |
| Subfamily: | † Polycotylinae |
| Genus: | † Eopolycotylus Albright, Gillette, and Titus, 2007 |
| Species | |
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Eopolycotylus is a genus of polycotylid plesiosaur known from the Cenomanian-age Tropic Shale of Utah. [1]
Nothronychus is a genus of therizinosaurid theropod dinosaurs that lived in North America during the Late Cretaceous period. The type species, Nothronychus mckinleyi, was described by James Kirkland and Douglas G. Wolfe in 2001. It was recovered near New Mexico's border with Arizona, in an area known as the Zuni Basin, from rocks assigned to the Moreno Hill Formation, dating to the Turonian stage of the Late Cretaceous. A second specimen, described in 2009 as a second species, Nothronychus graffami, was found in the Tropic Shale of Utah, dating between one million and a half million years older than N. mckinleyi.
Plesiopleurodon is an extinct genus of Mesozoic marine reptiles, belonging to the Sauropterygia, known from the Late Cretaceous of North America. It was named by Kenneth Carpenter based on a complete skull with a mandible, cervical vertebra, and a coracoid. In naming the specimen, Carpenter noted "Of all known pliosauroids, Plesiopleurodon wellesi most closely resembles Liopleurodon ferox from the Oxfordian of Europe, hence the generic reference." It was initially described as a pliosauroid due to it short neck, a common trait of the superfamily. However, later exploration into the relationships of both groups indicate that not all pliosauroids have short necks and not all plesiosauroids have long necks. Later research indicates it is a member of the Polycotylidae, within the clade Occultonectia.
Polycotylidae is a family of plesiosaurs from the Cretaceous, a sister group to Leptocleididae. They are known as false pliosaurs. Polycotylids first appeared during the Albian stage of the Early Cretaceous, before becoming abundant and widespread during the early Late Cretaceous. Several species survived into the final stage of the Cretaceous, the early Maastrichtian around 72 million years ago. The possible latest surviving member Rarosaurus from the late Maastrichtian is more likely a crocodylomorph.
Dolichorhynchops is an extinct genus of polycotylid plesiosaur from the Late Cretaceous of North America, containing the species D. osborni and D. herschelensis, with two previous species having been assigned to new genera. Definitive specimens of D. osborni have been found in the late Coniacian to early Campanian rocks, while those of D. herschelensis have been found in the late Campanian to early Maastrichtian rocks. Dolichorhynchops was a prehistoric marine reptile measuring around 3 metres (9.8 ft) long. Its Greek generic name means "long-nosed face".
Styxosaurus is a genus of plesiosaur of the family Elasmosauridae. Styxosaurus lived during the Campanian age of the Cretaceous period. Three species are known: S. snowii, S. browni, and S. rezaci.
Brancasaurus is a genus of plesiosaur which lived in a freshwater lake in the Early Cretaceous of what is now North Rhine-Westphalia, Germany. With a long neck possessing vertebrae bearing distinctively-shaped "shark fin"-shaped neural spines, and a relatively small and pointed head, Brancasaurus is superficially similar to Elasmosaurus, albeit smaller in size at 3.26 metres (10.7 ft) in length as a subadult.
Polycotylus is a genus of plesiosaur within the family Polycotylidae. The type species is P. latippinis and was named by American paleontologist Edward Drinker Cope in 1869. Eleven other species have been identified. The name means 'much-cupped vertebrae', referring to the shape of the vertebrae. It lived in the Western Interior Seaway of North America toward the end of the Cretaceous. One fossil preserves an adult with a single large fetus inside of it, indicating that Polycotylus gave live birth, an unusual adaptation among reptiles.
Palmulasaurus is a genus of polycotylid plesiosaur from the Turonian Tropic Shale of Utah. It was originally described as Palmula, but the name was occupied by a genus of Cretaceous foraminifer first described in 1833.
The Tropic Shale is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation, including Nothronychus graffami. The Tropic Shale is a stratigraphic unit of the Kaiparowits Plateau of south central Utah. The Tropic Shale was first named in 1931 after the town of Tropic where the Type section is located. The Tropic Shale outcrops in Kane and Garfield counties, with large sections of exposure found in the Grand Staircase–Escalante National Monument.
The Mowry Shale is an Early Cretaceous geologic formation. The formation was named for Mowrie Creek, northwest of Buffalo in Johnson County, Wyoming.
The Straight Cliffs Formation is a stratigraphic unit in the Kaiparowits Plateau of south central Utah. It is Late Cretaceous in age and contains fluvial, paralic, and marginal marine (shoreline) siliciclastic strata. It is well exposed around the margin of the Kaiparowits Plateau in the Grand Staircase – Escalante National Monument in south central Utah. The formation is named after the Straight Cliffs, a long band of cliffs creating the topographic feature Fiftymile Mountain.
The Lake Waco Formation is a geologic formation within the Eagle Ford Group deposited during the Middle Cenomanian to the Early Turonian of the Late Cretaceous in central Texas. The formation was named for outcrops near Lake Waco, south of the city of Waco, Texas by W. S. Adkins and F. E. Lozo in 1951. The Lake Waco Formation is primarily composed of shale, with minor amounts of limestone and volcanic ash beds (bentonites). It is subdivided into three members: Bluebonnet Member, Cloice Member, and the Bouldin Member. The Bluebonnet Member is 10 to 20 ft thick, and is made up of broken pieces (prisms) of inoceramid clams and planktonic foraminifera. The Cloice Member is 35 ft thick at its type section on the Cloice Branch of the South Bosque River, whereas the Bouldin Member was named for outcrops on Bouldin Creek south of downtown Austin, where it is roughly 9 ft thick. They are both made up of shales rich in organic matter with thin limestones and volcanic ash beds.
The Britton Formation is a geologic formation deposited during the Middle Cenomanian to the Early Turonian ages of the Late Cretaceous in modern-day East Texas. It forms the lower half of the Eagle Ford Group in the northern portion of East Texas. The formation was named by W. L. Moreman in 1932 for outcrops on Mountain Creek near the small town of Britton, south of Dallas. In the Dallas area it has been subdivided into the Six Flags Limestone, Turner Park Member, and Camp Wisdom Member. The Six Flags Limestone is a 3 ft thick fossiliferous calcarenite made up of pieces (prisms) of Inoceramus clams. The Turner Park and Camp Wisdom Members were subdivided based on the numerous volcanic ash beds (bentonites) found in the Turner Park, and the common occurrence of concretions in the Camp Wisdom. They are approximately 120 ft and 250 ft thick in the Dallas area. Thin sandstones known as the Templeton Member are found in Grayson County, north of Dallas, that are age equivalent to the lower part of the Turner Park Member. The Templeton Member was originally described as a part of the Woodbine, but it was recently placed in the Britton Formation of the Eagle Ford Group based on its age as derived by ammonites. Plesiosaur remains are among the vertebrate fossils that have been recovered from its strata.
Palmula is an extinct genus of foraminifera which is known from a number of species found in rocks dating from near the beginning of the Jurassic to the end of the Cretaceous, in Africa, Asia, Europe, and New Zealand. A genus of polycotylid plesiosaur was named Palmula in 2007, but because the name was already in use, the plesiosaur was renamed, becoming Palmulasaurus.
Megacephalosaurus is an extinct genus of short-necked pliosaur that inhabited the Western Interior Seaway of North America about 94 to 93 million years ago during the Turonian stage of the Late Cretaceous, containing the single species M. eulerti. It is named after its large head, which is the largest of any plesiosaur in the continent and measures up to 1.75 meters (5.7 ft) in length. Megacephalosaurus was one of the largest marine reptiles of its time with an estimated length of 6–9 meters (20–30 ft). Its long snout and consistently sized teeth suggest that it preferred a diet of smaller-sized prey.
The Eagle Ford Group is a sedimentary rock formation deposited during the Cenomanian and Turonian ages of the Late Cretaceous over much of the modern-day state of Texas. The Eagle Ford is predominantly composed of organic matter-rich fossiliferous marine shales and marls with interbedded thin limestones. It derives its name from outcrops on the banks of the West Fork of the Trinity River near the old community of Eagle Ford, which is now a neighborhood within the city of Dallas. The Eagle Ford outcrop belt trends from the Oklahoma-Texas border southward to San Antonio, westward to the Rio Grande, Big Bend National Park, and the Quitman Mountains of West Texas. It also occurs in the subsurface of East Texas and South Texas, where it is the source rock for oil found in the Woodbine, Austin Chalk, and the Buda Limestone, and is produced unconventionally in South Texas and the "Eaglebine" play of East Texas.
Mauriciosaurus is a genus of polycotylid plesiosaur from the Late Cretaceous of Mexico. It contains a single species, M. fernandezi, described in 2017 by Eberhard Frey and colleagues from a single well-preserved juvenile specimen about 1.9 metres long. Morphologically, it is overall most similar to the polycotyline polycotylids Trinacromerum and Dolichorhynchops. However, several features separate Mauriciosaurus from all other polycotylids, warranting the naming of a new genus. These include the sophisticated pattern of ridges on the bottom of the parasphenoid bone on its palate; the narrow openings in the palate bordered by the pterygoid bones; the lack of perforations in the surface of the coracoid; and the highly unusual arrangement of gastralia, or belly ribs, which is only otherwise seen in the non-polycotylid Cryptoclidus.
Naomichelys is an extinct genus of helochelydrid stem turtle known from the Cretaceous (Aptian-Campanian) of North America. It is the only member of the family known to be native to North America.
Scalamagnus is an extinct genus of polycotylid plesiosaur from the Late Cretaceous Tropic Shale Formation of the United States. The genus contains a single species S. tropicensis, known from a skull and two partial skeletons. Scalamagnus was historically considered to represent a species of the genus Dolichorhynchops before it was moved to its own genus.
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