| Ogmodirus Temporal range: Late Cretaceous, | |
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| Paddle bone of KUVP 441 | |
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| Cervical series of KUVP 441 | |
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| Genus: | †Ogmodirus |
| Binomial name | |
| †Ogmodirus martini Williston & Moodie, 1913 | |
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Ogmodirus is an extinct genus of plesiosaur found in the Cenomanian-Turonian (Late Cretaceous) Greenhorn Limestone of Kansas. [1] [2] The type species, O. martini, was named by Samuel Wendell Williston and Roy Lee Moodie in 1913. [2]
The holotype, KUVP 441, consists of a pelvic girdle, limb elements, and more than fifty cervical (neck) vertebrae from a juvenile discovered in Cloud County, Kansas by C. Boyce in 1909. [2] KUVP 441 was named as Ogmodirus martini by Williston & Moodie (1913) [2] and the specific name was emended to martinii by Moodie (1916), but the original name takes precedence. [3] The holotype was described in detail by Williston & Moodie (1917). [3]
A second species, Ogmodirus ischiadicus (based on specimen KUVP 434), was initially placed within its own genus, Thalassiosaurus, [3] and has since been referred to Styxosaurus . [4] It was placed in Ogmodirus by Willison & Moodie (1917). [3]
According to Welles (1962), [5] Ogmodirus martini may be member of the Elasmosauridae, a group of marine animals related to Elasmosaurus , but the condition of the fossils discovered to date means the genus is dubious beyond Plesiosauria. Sepkoski (2002) assigned Ogmodirus to the Plesiosauria. [6]
Plesiosauroidea is an extinct clade of carnivorous marine reptiles. They have the snake-like longest neck to body ratio of any reptile. Plesiosauroids are known from the Jurassic and Cretaceous periods. After their discovery, some plesiosauroids were said to have resembled "a snake threaded through the shell of a turtle", although they had no shell.
Plesiosaurus is a genus of extinct, large marine sauropterygian reptile that lived during the Early Jurassic. It is known by nearly complete skeletons from the Lias of England. It is distinguishable by its small head, long and slender neck, broad turtle-like body, a short tail, and two pairs of large, elongated paddles. It lends its name to the order Plesiosauria, of which it is an early, but fairly typical member. It contains only one species, the type, Plesiosaurus dolichodeirus. Other species once assigned to this genus, including P. brachypterygius, P. guilielmiimperatoris, and P. tournemirensis have been reassigned to new genera, such as Hydrorion, Seeleyosaurus and Occitanosaurus.
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.
The Plesiosauria or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
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.
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".
Brachauchenius is an extinct genus of pliosaurs that lived during the Late Cretaceous in what are now North America and North Africa. Only one species is known, B. lucasi, initially described by Samuel Wendell Williston in 1903 from a partial fossil skeleton discovered in a quarry in Kansas, United States. Many other fossil specimens attributed to the species were subsequently discovered, including an individual from Morocco whose presence was made official in 2016. Many contemporary pliosaur specimens were formerly attributed to Brachauchenius, but have since been reidentified as belonging to other genera or are recognized as indeterminate.
Megalneusaurus is an extinct genus of large pliosaurs that lived during the Oxfordian and Kimmeridgian stages of the Late Jurassic in what is now North America. It was provisionally described as a species of Cimoliosaurus by the geologist Wilbur Clinton Knight in 1895, before being given its own genus by the same author in 1898. The only species identified to date is M. rex, known from several specimens identified in the Redwater Shale Member, within the Sundance Formation, Wyoming, United States. A specimen discovered in the Naknek Formation in southern Alaska was referred to the genus in 1994. In Ancient Greek, the generic name literally translates to "large swimming lizard", due to the measurement of the fossils of the holotype specimen.
Aptychodon is an extinct genus of plesiosaur from the Late Cretaceous of the Czech Republic. The type species is A. cretaceus.
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.
Attenborosaurus is an extinct genus of pliosaurid from the Early Jurassic of Dorset, England. The type species is A. conybeari. The genus is named after David Attenborough, the species after William Conybeare.
Archaeonectrus is an extinct genus of pliosaur from the Early Jurassic (Sinemurian) of what is now southeastern England. The type species is Archaeonectrusrostratus, first named by Sir Richard Owen in 1865, which was moved to its own genus by N.I. Novozhilov in 1964. It was a relatively small plesiosaur, measuring 3.4–3.67 m (11.2–12.0 ft) long.
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.
Morenosaurus is an extinct genus of plesiosaur from the Cretaceous of what is now California. The type species is Morenosaurus stocki, first named by Samuel Welles in 1943, in honor of Dr. Chester Stock. The species was found by Robert Wallace and Arthur Drescher in the Panoche Hills region of Fresno County. The skeleton they found was fairly complete, and lacked only the head and parts of the neck and paddles; the preserved portion of the trunk and tail is 3.63 metres (11.9 ft) long. The skeleton was originally mounted at Caltech but is now in the Natural History Museum of Los Angeles County.
Fresnosaurus is an extinct genus of plesiosaur from the Late Cretaceous of what is now California. The type species is Fresnosaurus drescheri, first described by Welles in 1943. The generic name Fresnosaurus honors Fresno County, while the specific name honors Arthur Drescher.
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.
Sthenarosaurus is an extinct genus of rhomaleosaurid pliosauroid discovered in the Toarcian-aged 'Main Alum Shale' in Whitby, England. The type species, Sthenarosaurus dawkinsi, was named and described in 1909 by D. M. S. Watson. The type specimen is MMUM LL 8023, a set of postcrania discovered in Whitby. Other indeterminate specimens are known, including a pectoral girdle described in 1911. Plesiosaurian fossils were acquired for the Manchester Museum by William Boyd Dawkins who is honoured by the specific name.
Piratosaurus is a dubious genus of plesiosaur possibly belonging to the Polycotylidae that is known exclusively from the type species P. plicatus, named and described by Joseph Leidy in 1865. It is known only from the holotype, USNM V 1000, a tooth, discovered in Late Cretaceous-aged rocks in the Red River basin of Manitoba; at least one researcher erroneously assumed it was found in Minnesota.
Antofagastaichthys is an extinct genus of ray-finned fish that lived in what is now Chile during the Oxfordian stage of the Late Jurassic epoch. It contains one species, A. mandibularis, which is known from several fragmentary specimens discovered in the El Profeta Formation of Antofagasta Province.
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.
