| Cimoliasaurus Temporal range: Late Cretaceous, | |
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| Cimoliasaurus magnus vertebrae. | |
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| Genus: | †Cimoliasaurus Leidy, 1851 |
| Type species | |
| †Cimoliasaurus magnus Leidy, 1851 | |
Cimoliasaurus was a plesiosaur that lived during the Late Cretaceous (Maastrichtian) of New Jersey.
The name is derived from the Greek Κιμωλίαkimolia, meaning "white chalk", and σαύροςsauros, meaning "lizard", in reference to the fact that the deposits in which it was found bear a superficial resemblance to the chalk deposits of the Western Interior Seaway.
The name Cimoliasaurus magnus was coined by Joseph Leidy for ANSP 9235, one anterior and 12 posterior cervical vertebrae collected in Maastrichtian-aged greensand deposits in Burlington County, New Jersey. [1]
In his catalogue of plesiosaur and ichthyosaur specimens preserved in the NHM, the British zoologist Richard Lydekker referred several Jurassic and Cretaceous plesiosaur species to Cimoliasaurus, including the new species C. richardsoni (now considered a species of Cryptoclidus ) and C. cantabrigiensis, as well as Colymbosaurus and a number of previously described species from the Cambridge Greensand and Chalk Group. [2]
Nowadays, Cimoliasaurus is now recognized as being a derived elasmosaurid, effectively making the family name Cimoliasauridae Delair, 1959 a junior synonym of Elasmosauridae. [3]
Trachodon is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-age Upper Cretaceous Judith River Formation of Montana, U.S. It is a historically important genus with a convoluted taxonomy that has been all but abandoned by modern dinosaur paleontologists.
Elasmosaurus is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, about 80.5 million years ago. The first specimen was discovered in 1867 near Fort Wallace, Kansas, US, and was sent to the American paleontologist Edward Drinker Cope, who named it E. platyurus in 1868. The generic name means "thin-plate reptile", and the specific name means "flat-tailed". Cope originally reconstructed the skeleton of Elasmosaurus with the skull at the end of the tail, an error which was made light of by the paleontologist Othniel Charles Marsh, and became part of their "Bone Wars" rivalry. Only one incomplete Elasmosaurus skeleton is definitely known, consisting of a fragmentary skull, the spine, and the pectoral and pelvic girdles, and a single species is recognized today; other species are now considered invalid or have been moved to other genera.
Diplotomodon is a dubious genus of theropod dinosaur, from New Jersey. It was possibly a member of the Tyrannosauroidea, the clade that also contains Tyrannosaurus.
Macrurosaurus is the name given to a genus of dinosaur from the Early Cretaceous. It was a titanosauriform which lived in what is now England. The type species, M. semnus, was named in 1876. A second species, M. platypus, may also exist.
Elasmosauridae is an extinct family of plesiosaurs, often called elasmosaurs. They had the longest necks of the plesiosaurs and existed from the Hauterivian to the Maastrichtian stages of the Cretaceous, and represented one of the two groups of plesiosaurs present at the end of the Cretaceous alongside Polycotylidae.
Protosphyraena is a fossil genus of swordfish-like marine fish, that thrived worldwide during the Upper Cretaceous Period (Coniacian-Maastrichtian). Though fossil remains of this taxon have been found in both Europe and Asia, it is perhaps best known from the Smoky Hill Member of the Niobrara Chalk Formation of Kansas. Protosphyraena was a large fish, averaging 2–3 metres in length. Protosphyraena shared the Cretaceous oceans with aquatic reptiles, such as mosasaurs and plesiosaurs, as well as with many other species of extinct predatory fish. The name Protosphyraena is a combination of the Greek word protos ("early") plus Sphyraena, the genus name for barracuda, as paleontologists initially mistook Protosphyraena for an ancestral barracuda. Recent research shows that the genus Protosphyraena is not at all related to the true swordfish-family Xiphiidae, but belongs to the extinct family Pachycormidae.
Cretornis is a pterosaur genus from the late Cretaceous period of what is now the Jizera Formation in the Czech Republic, dating to about 92 million years ago. It only contains a single species, Cretornis hlavaci.
Scanisaurus is a dubious genus of plesiosaur that lived in what is now Sweden and Russia during the Campanian stage of the Late Cretaceous period. The name Scanisaurus means "Skåne lizard", Skåne being the southernmost province of Sweden, where a majority of the fossils referred to the genus have been recovered. The genus contains one species, S. nazarowi, described in 1911 by Nikolay Bogolyubov as a species of Cimoliasaurus based on a single vertebral centrum discovered near Orenburg, Russia.
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.
Kimmerosaurus is an extinct genus of plesiosaur from the family Cryptoclididae. Kimmerosaurus is most closely related to Tatenectes.
Aristonectes is an extinct genus of large elasmosaurid plesiosaurs that lived during the Maastrichtian stage of the Late Cretaceous. Two species are known, A. parvidens and A. quiriquinensis, whose fossil remains were discovered in what are now Patagonia and Antarctica. Throughout the 20th century, Aristonectes was a difficult animal for scientists to analyze due to poor fossil preparation, its relationships to other genera were uncertain. After subsequent revisions and discoveries carried out from the beginning of the 21st century, Aristonectes is now recognised as the type genus of the subfamily Aristonectinae, a lineage of elasmosaurids characterized by an enlarged skull and a reduced length of the neck.
Brimosaurus is an extinct genus of plesiosaur from the Late Cretaceous of what is now Arkansas. The type species is Brimosaurus grandis, first named by Joseph Leidy in 1854. The name Brimosaurus is a nomen dubium: the fossils consist of only a few isolated vertebrae, and in 1952 Welles proposed that Brimosaurus was actually synonymous with Cimoliasaurus.
Discosaurus is an extinct genus of plesiosaur from the Santonian of Alabama and Mississippi. One species is known, which is D. vestutus.
Crymocetus is an extinct genus of plesiosaur from the Late Cretaceous Chalk Group of Sussex, England. It is only known from the type species, which is C. bernardi.
Tatenectes is a genus of cryptoclidid plesiosaur known from the Upper Jurassic of Wyoming. Its remains were recovered from the Redwater Shale Member of the Sundance Formation, and initially described as a new species of Cimoliosaurus by Wilbur Clinton Knight in 1900. It was reassigned to Tricleidus by Maurice G. Mehl in 1912 before being given its own genus by O'Keefe and Wahl in 2003. Tatenectes laramiensis is the type and only species of Tatenectes. While the original specimen was lost, subsequent discoveries have revealed that Tatenectes was a very unusual plesiosaur. Its torso had a flattened, boxy cross-section and its gastralia exhibit pachyostosis (thickening). The total length of Tatenectes has been estimated at 2–3 meters (6.6–9.8 ft).
The Aristonectidae is a taxonomic family of poorly known plesiosaurs from the Jurassic and Cretaceous periods. They are closely related to polycotylid plesiosaurs. The family is made up of Tatenectes, Kimmerosaurus, Aristonectes, and Kaiwhekea. This group was formerly known as the Cimoliasauridae, but since Cimoliasaurus is indeterminate and quite possibly elasmosaurid, this replacement name was erected.
Cretalamna is a genus of extinct otodontid shark that lived from the latest Early Cretaceous to Eocene epoch. It is considered by many to be the ancestor of the largest sharks to have ever lived, such as Otodus angustidens, Otodus chubutensis, and Otodus megalodon.
This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles that flourished during the Mesozoic Era. The first scientifically documented plesiosaur fossils were discovered during the early 19th century by Mary Anning. Plesiosaurs were actually discovered and described before dinosaurs. They were also among the first animals to be featured in artistic reconstructions of the ancient world, and therefore among the earliest prehistoric creatures to attract the attention of the lay public. Plesiosaurs were originally thought to be a kind of primitive transitional form between marine life and terrestrial reptiles. However, now plesiosaurs are recognized as highly derived marine reptiles descended from terrestrial ancestors.
