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Elasmosaurids
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. Their diet mainly consisted of crustaceans and molluscs. Description The earliest elasmosaurids were mid-sized, about . In the Late Cretaceous, elasmosaurids grew as large as , such as ''Styxosaurus'', ''Albertonectes'', and '' Thalassomedon''. Their necks were the longest of all the plesiosaurs, with anywhere between 32 and 76 (''Albertonectes'') cervical vertebrae. They weighed up to several tons. Classification Early three-family classification Though Cope had originally recognized ''Elasmosaurus'' as a plesiosaur, in an 1869 paper he placed it, with ''Cimoliasaurus'' and ''Crymocetus'', in a new order of sauropterygian reptiles. He named the group Streptosaur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elasmosaurus Platyurus
''Elasmosaurus'' (;) is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, about 80.5million 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 (biology), generic name means "thin-plate reptile", and the specific name (zoology), 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 girdle, pectoral and pelvic girdles, and a single species is recognized today; other species are now considered invalid or have been moved to other genera. Measuring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elasmosaurus
''Elasmosaurus'' (;) is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, about 80.5million 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. Measuring in length and in body mass, ''Elasmosaurus'' would have ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalassomedon
''Thalassomedon'' (from Greek, ''thalassa'', "sea" and Greek, ''medon'', "lord" or "ruler", meaning "sea lord") is a genus of plesiosaur, named by Welles in 1943. Description ''Thalassomedon'' is among the largest elasmosaurids, with a total length of for the holotype. There is a larger skull, however, suggesting a much larger animal, potentially up to . Gregory S. Paul proposed that a long individual would have weighed , while O'Gorman and his colleagues proposed that a long individual would have weighed more than . The neck is also very long; it comprises 62 vertebraeCarpenter, K. (1999). "Revision of North American elasmosaurs from the Cretaceous western interior." ''Paludicola'', 2(2): 148-173. and is about - over half of the total length. The skull is long, with long teeth. The flippers were about long. Stones have been found in its stomach area leading some to theorize that they were used for ballast or digestion. If the latter, stomach action would cause the stone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morenosaurus
''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.Hilton, Richard P., ''Dinosaurs and Other Mesozoic Animals of California'', University of California Press, Berkeley 2003 , at page 105 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 long. The skeleton was originally mounted at Caltech but is now in the Natural History Museum of Los Angeles County. ''Morenosaurus'' may have been similar to ''Elasmosaurus'' or ''Thalassomedon'', but studies in the early 2000s indicated that the fossils were too scrappy to identify to the family level. See also * List of plesiosaur genera * Timeline of plesiosaur research Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kawanectes
''Kawanectes'' (meaning "Kawas swimmer") is a genus of elasmosaurid plesiosaur, a type of long-necked marine reptile, that lived in the marginal marine ( estuarine) environment of Late Cretaceous Patagonia. It contains one species, ''K. lafquenianum'', described in 2016 by O'Gorman. Description At in body length and in body mass, ''Kawanectes'' was small for an elasmosaurid. It belongs to the "non-elongated" group of elasmosaurids, meaning that its cervical vertebrae are not extremely lengthened, neither do they show great variability in length. The MCS specimen preserves 15 cervical vertebrae and 15 dorsal vertebrae, while the holotype preserves 10 caudal vertebrae; the true number of cervical and caudal vertebrae is unknown due to the incompleteness of the specimens. A combination of traits can be used to distinguish ''Kawanectes'' from all other elasmosaurids: the centra of the vertebrae are wider than they are long; the projections known as the parapophyses on the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Futabasaurus
''Futabasaurus'' is a genus of plesiosaur from the Late Cretaceous of Fukushima, Japan. It was described and named in 2006, and was assigned to the family Elasmosauridae. The genus contains one species, ''F. suzukii''. Description The size of ''Futabasaurus'' has been estimated within the range of in length and in body mass. It can be distinguished from other elasmosaurids by the following characteristics: there is a long distance between the eye sockets and nostrils; the interclavicles and clavicles are fused, and the anterior edge is bent; the humerus is relatively long; and the femora are slim and show prominent muscle scars. Discovery and naming ''Futabasaurus'' is the first elasmosaurid found in Japan. It was originally known as either "Wellesisaurus sudzuki" or "Futaba-ryu" before publication. The type specimen of ''Futabasaurus'' was found in the Irimazawa Member of the Tamayama Formation, in the Futaba Group of Fukushima Prefecture, Japan. The rocks in which it were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrotherosaurus
''Hydrotherosaurus'' (meaning "water beast lizard") is an extinct genus of elasmosaurid plesiosaur from the Upper Cretaceous (Maastrichtian stage) Moreno Formation of Fresno County, California, USA. The only known species, ''H. alexandrae'', was named for its discoverer, Annie Montague Alexander, by Samuel Paul Welles. Description ''Hydrotherosaurus'' measured approximately in length. It has one of the longest necks relative to total length among elasmosaurids, with 60 vertebrae in total. It had a small head that measured about long, a streamlined body, and four large flippers that were specially designed to help the huge animal balance, move, and accelerate itself. See also * List of plesiosaur genera * Timeline of plesiosaur research 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libonectes
''Libonectes'' is an extinct genus of sauropterygian reptile belonging to the plesiosaur order. It is known from specimens found in the Britton Formation of Texas (USA) and the Akrabou Formation of Morocco, which have been dated to the lower Turonian stage of the late Cretaceous period. Nomenclature The prefix "''libo''" comes from Greek, and means "southern," translated to English. "''Nectes''," the suffix, is also from Greek, and translates to "swimmer." In its entirety, ''Libonectes'' can be interpreted as "southern swimmer." ''Libonectes'' was an elasmosaurid plesiosaur, with many specimens unearthed in southern parts of North America- as a result, it was labeled with such a name as described in the preceding sentence. C.G. Morgan is credited with the discovery of the first ''Libonectes'' fossils, and it was for this reason that ''morgani'' was chosen as its binomial name. Description The animal was very similar to the related '' Thalassomedon'', though the structure of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Styxosaurus
''Styxosaurus'' is a genus of plesiosaur of the family Elasmosauridae. ''Styxosaurus'' lived during the Campanian age of the Cretaceous period. Two species are known: ''S. snowii'' and ''S. browni''. Description ''Styxosaurus'' was a large plesiosaur, one of several species of a group collectively called elasmosaurs that appeared in the Late Cretaceous. Elasmosaurs typically have a neck that is at least half the length of the body, and composed of 60-72 vertebrae. ''Styxosaurus'' was a large elasmosaur with a long neck. It reached in length and in body mass. Its sharp teeth were conical and were adapted to puncture and hold rather than to cut; like other plesiosaurs, ''Styxosaurus'' swallowed its food whole. Discovery The holotype specimen of ''Styxosaurus snowii'' was described by S.W. Williston from a complete skull and 20 vertebrae. Another more complete specimen - SDSMT 451 was discovered near Iona, South Dakota, also in the US, in 1945. The specimen was originally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminonatator
''Terminonatator'' (meaning "last swimmer") is a genus of elasmosauridae, elasmosaurid plesiosaur from the Late Cretaceous of Saskatchewan, Canada. It is known from a skull and partial skeleton from a young adult, found in the Campanian-age Bearpaw Formation near Notukeu Creek in Ponteix. ''Terminonatator'' is currently one of the youngest plesiosaurs from the Western Interior Seaway. Description ''Terminonatator'' is holotype, based on Royal Saskatchewan Museum, RSM P2414.1, a skull and partially articulated incomplete skeleton found high in the Bearpaw Formation. Tamaki Sato, who named and described the specimen in 2003 in paleontology, 2003, used the genus name to emphasize its lateness in the fossil record, and the species epithet ''ponteixensis'' for Ponteix. Only one species has been described: the type species ''T. ponteixensis''. RSM P2414.1 appears to represent an adult, because the vertebral arch, neural arches are fused to their vertebrae, although incomplete fus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluvionectes
''Fluvionectes'' (meaning "river swimmer", from both Latin and Greek) is a genus of elasmosaurid plesiosaur found in the Dinosaur Park Formation in Alberta, Canada. It is known from a holotype, which includes parts of the trunk area, and from a much larger specimen referred to this taxon. Description The holotype of ''Fluvionectes'' reached long and weighed . A much larger specimen indicates that this taxon may have reached in maximum body length. Classification The describers placed ''Fluvionectes'' in the Elasmosauridae, in a clade with ''Albertonectes'', ''Nakonanectes'', ''Styxosaurus'', and ''Terminonatator'', which by definition places it in the Elasmosaurinae subfamily. Paleobiology ''Fluvionectes'' appears to have been a freshwater (and possibly brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albertonectes
''Albertonectes'' is an extinct genus of elasmosaurid plesiosaur known from the Late Cretaceous (middle upper Campanian stage) Bearpaw Formation of Alberta, Canada. It contains a single species, ''Albertonectes vanderveldei''. ''Albertonectes'' is the longest elasmosaur, and more generally plesiosaur, known to date both in neck and total body length. Discovery ''Albertonectes'' is known solely from the holotype TMP 2007.011.0001, a complete well preserved postcranial skeleton housed at the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta. Elements include all 132 vertebrae from the atlas-axis complex to fused tip of the tail vertebrae, complete pectoral and incomplete pelvic girdles, almost complete forelimbs and hindlimbs, disarticulated ribs, a gastralium, and at least 97 associated gastroliths. TMP 2007.011.0001 was discovered during mining for gem-quality ammonite shell called Ammolite by Korite International Ltd. about 150 meters south of the St. M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
