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Rhomaleosauridae
Rhomaleosauridae is a family of plesiosaurs from the Earliest Jurassic to the latest Middle Jurassic (Hettangian to Callovian stages) of Europe, North America, South America and possibly Asia. Most rhomaleosaurids are known from England, many specifically from lower Blue Lias deposits that date back to the earliest Jurassic, just at the boundary with the Triassic. In fact, to date only two undisputed rhomaleosaurids were named from outside Europe - the closely related '' Borealonectes russelli'' and '' Maresaurus coccai'' from Canada and Argentina, respectively. These two species are also the only Middle Jurassic representatives of the family. Rhomaleosauridae was formally named by Kuhn in 1961, originally proposed to include '' Rhomaleosaurus cramptoni'' and its relatives, which have short necks and large heads relatively to plesiosauroids like '' Elasmosaurus'' and '' Plesiosaurus'', but longer necks and smaller heads relatively to advanced pliosaurids like '' Pliosaurus'' a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atychodracon
''Atychodracon'' is an extinct genus of rhomaleosaurid plesiosaurian known from the Late Triassic - Early Jurassic boundary (probably early Hettangian stage) of England. It contains a single species, ''Atychodracon megacephalus'', named in 1846 originally as a species of ''Plesiosaurus''. The holotype of ''"P." megacephalus'' was destroyed during a World War II air raid in 1940 and was later replaced with a neotype. The species had a very unstable taxonomic history, being referred to four different genera by various authors until a new genus name was created for it in 2015. Apart from the destroyed holotype and its three partial casts (that survived), a neotype and two additional individuals are currently referred to ''Atychodracon megacephalus'', making it a relatively well represented rhomaleosaurid. History of discovery The type species of ''Atychodracon'' was first described and named by Samuel Stutchbury in January 1846, as a species of the wastebasket taxon ''Plesiosauru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhomaleosaurus Cramptoni
''Rhomaleosaurus'' (meaning "strong lizard") is an extinct genus of Early Jurassic (Toarcian Faunal stage, age, about 183 to 175.6 million years ago) rhomaleosaurid pliosauroid known from Northamptonshire and from Yorkshire of the United Kingdom. It was first named by Harry Seeley in 1874 in paleontology, 1874 and the type species is ''Rhomaleosaurus cramptoni''. It was one of the earliest large marine reptile predators which hunted in the seas of Mesozoic era, measuring about long. Like other pliosaurs, ''Rhomaleosaurus'' fed on ichthyosaurs, ammonites and other Plesiosauria, plesiosaurs. Species ''R. cramptoni'' In July 1848, a fossil of a large plesiosaur was unearthed in an alum quarry at Kettleness, near Whitby, in Yorkshire, England. It was collected from the ''A. bifrons'' ammonite zone of the Whitby Mudstone Formation, dating to the early Toarcian age, about 183 to 180 million years ago. The complete skeleton which preserved the skull, National Museum of Ireland, NMING& ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosaur
The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution, and some species at least partly inhabited freshwater environments. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous ''Plesiosaurus'', was named in 1821. Since then, more than a hundred valid species have been described. In the early twenty-first cent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurycleidus
''Eurycleidus'' is an extinct genus of large-bodied rhomaleosaurid known from the Early Jurassic period (most likely earliest Hettangian stage) of the United Kingdom. It contains a single species, ''E. arcuatus''. Discovery and naming The currently accepted remains that belong to ''Eurycleidus arctuatus'' consist of syntypes BMNH 2027, 2028, 2029, 2030, and associated specimens BMNH R.1317 en R.1318, BMNH 2047, BMNH 2061 and BMNH R.1319. They were acquired by Thomas Hawkins during the early 1830s from a quarry in Street, Somerset and he described them in 1834. In 1837, Richard Owen erroneously believed the remains had been found in Lyme Regis, and in 1840 he assigned them to ''Plesiosaurus'' under the newly created species ''P. arcuatus''. In 1889 Richard Lydekker moved the species to the genus '' Thaumatosaurus'' as ''T. arcuatus''. Lydekker stated that specimen BMNH 2030, a symphysis of the lower jaws, was the holotype, although it can at most be a lectotype. He believed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trematospondylus
''Trematospondylus'' ("hole spinner"Sachs, S., Abel, P. und Madzia, D. (2023) A ‘long-forgotten’ plesiosaur provides evidence of large-bodied rhomaleosaurids in the Middle Jurassic of Germany, ''Journal of Vertebrate Paleontology'' 42(5). doi:10.1080/02724634.2023.2205456.) is a dubious genus of plesiosaurs from the Middle Jurassic of Baden-Württemberg, Germany. The only named species is ''Trematospondylus macrocephalus''. It is one of the earliest scientifically described plesiosaurs and historically has been the first plesiosaur named from Germany. Preserved remains include seven vertebrae. Research history ''T. macrocephalus'' was first named by Quenstedt in 1858, who found the fossils in the layers of the Dentalienton Formation at Lochen mountain massif in the Zollernalbkreis of Baden-Württemberg.Quenstedt, F. A. (1858). ''Der Jura''. Laupp’schen Buchhandlung. p. 466–467 Its species name likely derives from the Macrocephalus oolite that had been deposited directl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meyerasaurus
''Meyerasaurus'' is an extinct genus of rhomaleosaurid plesiosaur known from the Early Jurassic of Holzmaden, Baden-Württemberg in southwestern Germany. Discovery Between Holzmaden and Zell unter Aichelberg, a chalkstone and shale quarry was operated. It intersected an extremely hard forty centimetres thick layer of ''Stinkstein'' chalk, which was deemed worthless. Even ichthyosaur "mummies" present in the layer were discarded as it was not cost-effective to prepare them. The rocks were dumped in a ravine. In May 1906, the famous fossil trader Bernhard Hauff discovered in the dump broken-up boulders containing an uniquely complete and thus very rare plesiosaur skeleton. Up till that time, German plesiosaurs finds had tended to be much more fragmentary than British discoveries. Over nine months he recovered 2.5 tonnes of chalkstone, exposing and preparing the bones. Together with a second plesiosaurian skeleton, discovered nearby in shale in November 1906, much later referred t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macroplata
''Macroplata'' (meaning "big plate") is an extinct genus of Early Jurassic rhomaleosaurid plesiosaur which grew up to in length. Like other plesiosaurs, ''Macroplata'' probably lived on a diet of fish, using its sharp needle-like teeth to catch prey. Its shoulder bones were fairly large, indicating a powerful forward stroke for fast swimming. ''Macroplata'' also had a relatively long neck, twice the length of the skull, in contrast to pliosaurs. It is known from a nearly complete skeleton NHMUK PV R5488 (formerly BMNH R 5488) from the Blue Lias Formation (Hettangian) of Harbury, Warwickshire, UK. A different species, ''Macroplata longirostris'' (previously called ''Plesiosaurus longirostris''), which lived somewhat later, during the Toarcian stage, was also included in the genus; however, in 2011, Benson ''et al.'' reclassified it as a pliosaurid in the genus ''Hauffiosaurus'', ''H. longirostris''.R. B. J. Benson, H. F. Ketchum, L. F. Noe and M. Gomez-Perez. 2011. "New informat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratesaurus
''Stratesaurus'' is an extinct genus of small-bodied rhomaleosaurid plesiosaur known from the Early Jurassic period (most likely earliest Hettangian stage) of the United Kingdom. It contains a single species, ''S. taylori''. It was a small plesiosaur, with a skull length of and a body length of . Discovery ''Stratesaurus'' is known from the holotype specimen OUMNH J.10337, a dorsoventrally crushed but nearly complete skull, and three-dimensionally preserved partial postcranial skeleton including anterior cervical and pectoral vertebrae, a partial hindlimb and ilium. The specimen was acquired by the OUMNH in 1874 from the collection of Thomas Hawkins. GSM 26035 was referred to ''S. taylori'' because it shares one autapomorphy and other characters with the holotype specimen. It consists of a skull and some anterior cervical vertebrae. AGT 11 was also referred to ''S. taylori''. Although it does nor show the autapomorphies of ''S. taylori'', it is indistinguish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avalonnectes
''Avalonnectes'' is an extinct genus of small-bodied rhomaleosaurid known from the Early Jurassic period (most likely earliest Hettangian stage) of the United Kingdom. It contains a single species, ''A. arturi''. Discovery ''Avalonnectes'' is known from the holotype specimen NHMUK 14550, which consists of the posterior portion of a skull, and a nearly complete, three-dimensionally preserved and articulated postcranial skeleton. Another partial postcranial skeleton which was referred to it is AGT uncatalogued. Both specimens were collected at Street, of Somerset, from the Pre-''Planorbis'' beds of the Blue Lias Formation of the Lower Lias Group. These beds likely occur below the first occurrence of the ammonite '' Psiloceras planorbis''. Thus, they probably fall within the earliest Hettangian ''P. tilmanni'' Chronozone, which is about 199.6-198 million years old, immediately following the Triassic–Jurassic Boundary. Plesiosaurs fossils which were discovered at Street ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeonectrus
''Archaeonectrus'' is an extinction, extinct genus of pliosaur from the Early Jurassic (Sinemurian) of what is now southeastern England. The type species is ''Archaeonectrus'' (originally ''"Plesiosaurus"'') ''rostratus'', 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 long. Classification The cladogram below shows ''Archaeonectrus'' phylogenetic position among other plesiosaurs, following Benson ''et al.'' (2012). See also * Timeline of plesiosaur research * List of plesiosaur genera References * Sepkoski, J.J. (2002). "A compendium of fossil marine animal genera". ''Bulletins of American Paleontology'' 363: 1-560. External links ''Archaeonectrus'' in the Paleobiology Database {{Taxonbar, from1=Q4785513, from2=Q3621458, from3=Q41218758 Jurassic plesiosaurs of Europe Rhomaleosauridae Fossil taxa described in 1964 Sauropterygian genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borealonectes
''Borealonectes'' is a genus of rhomaleosaurid pliosauroid, a type of plesiosaur. Its fossils were found in the Callovian-age (Middle Jurassic, about 165-161 million years ago) Hiccles Cove Formation of Melville Island, Canada, one of the islands in the Canadian Arctic Archipelago. It is based on a skull, neck vertebrae, and the right forelimb of one individual. Named in 2008 by Sato and Wu, ''Borealonectes'' is one of the few plesiosaurs known from the Jurassic of North America, and the first marine reptile from the Canadian Arctic with a well-preserved skull. The type species is ''B. russelli.'' See also * Timeline of plesiosaur research * List of plesiosaur genera This list of plesiosaurs is a comprehensive listing of all genera that have ever been included in the order Plesiosauria, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered inv ... References Middle Jurassic plesiosaurs Middle J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
