Rhomaleosaurids
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'' and ''Kro ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Rhomaleosaurus Cramptoni
''Rhomaleosaurus'' (meaning "strong lizard") is an extinct genus of Early Jurassic (Toarcian 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 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, with the type species ''R. cramptoni'' measuring long and weighing . Like other pliosaurs, ''Rhomaleosaurus'' fed on ichthyosaurs, ammonites and other 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, NMING F8785, was kept for five ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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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''. Like other plesiosaurs, ''Eurycleidus'' 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. Phylogeny Most phylogenetic analyses find the type species of the genus, ''Eurycleidus arcuatus'', to be a relatively basal rhomaleosaurid. A second species, ''E. megacephalus'' (Stutchbury, 1846 riginally ''Rhomaleosaurus megacephalus''">Rhomaleosaurus.html" ;"title="riginally ''Rhomaleosaurus">riginally ''Rhomaleosaurus megacephalus'', was reassigned to this genus by Smith (2007). However, most analyses find ''E. megacephalus'' to represent an unnamed genus, which is distinct from both ''Eurycleidus'' and ''Rhomaleosaurus''. ''E. megacephalus'' was move ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Thaumatodracon
''Thaumatodracon'' is a genus of rhomaleosaurid pliosaur from the early Jurassic found in the United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North .... It contains a single species, named by Adam Smith and Ricardo Araújo in 2017. References Rhomaleosaurids Fossil taxa described in 2017 Sauropterygian genera {{jurassic-reptile-stub ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Rhomaleosaurus
''Rhomaleosaurus'' (meaning "strong lizard") is an extinct genus of Early Jurassic (Toarcian 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 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, with the type species ''R. cramptoni'' measuring long and weighing . Like other pliosaurs, ''Rhomaleosaurus'' fed on ichthyosaurs, ammonites and other 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, NMING F8785, was kept for five ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Meyerasaurus
''Meyerasaurus'' is an extinct genus of rhomaleosaurid known from Holzmaden, Baden-Württemberg of southwestern Germany. Description ''Meyerasaurus'' is known from the holotype SMNS 12478, articulated and complete skeleton which preserved the skull, exposed in ventral view. It has a skull length of , a body length of and a body mass of . It was collected from the ''Harpoceras elegantulum-falciferum'' ammonoid subzones, ''Harpoceras falcifer'' zone, of the famous Posidonien-Schiefer lagerstätte (Posidonia Shale), dating to the early Toarcian stage of the Early Jurassic, about 183-180 million years ago. Etymology ''Meyerasaurus'' was first named by Adam S. Smith and Peggy Vincent in 2010 and the type species is ''Meyerasaurus victor''. It was originally classified as a species of ''Plesiosaurus'', later as the second named species of ''Thaumatosaurus'' (defunct name, meaning "wonder reptile") and ultimately as a species of ''Eurycleidus'' or ''Rhomaleosaurus''. The gene ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Maresaurus
''Maresaurus'' is an extinct genus of plesiosaur from the Middle Jurassic (Bajocian) Los Molles Formation of Argentina. The type species, ''Maresaurus coccai'', was named by Gasparini in 1997. Recent phylogenetic analysis found ''Maresaurus'' to be a rhomaleosaurid.Smith AS, Dyke GJ. 2008. The skull of the giant predatory pliosaur ''Rhomaleosaurus cramptoni'': implications for plesiosaur phylogenetics. ''Naturwissenschaften'' e-published 2008. It was about long and weighed . 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 duri ... References External links * Smith, Adam S. and Dyke, Gareth J. (2008)The skull of the giant predatory pliosaur ''Rhomaleosaurus cramptoni'': implications for plesiosaur phylogenet ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Macroplata
''Macroplata'' (meaning "big plate") is an extinct genus of Early Jurassic rhomaleosaurid plesiosaur which grew up to in length and weighed up to . 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. 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''. Description ''Macroplata'' bore an elongated skull, with more than half of its cranial length taken up by a roughly triangular snout. The premaxillae (front upper jaw bones) bear six teeth each, with the first being ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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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. 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 indistinguishable from both OUMNH J.10337 and GSM 26035, and it is possible to distinguish i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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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]   |
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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]   |
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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, from=Q4785513 Jurassic plesiosaurs of Europe Rhomaleosaurids Fossil taxa described in 1964 Sauropterygian genera ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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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 ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |