Plesiosauria - Wikipedia. The Plesiosauria (. They had a worldwide oceanic distribution. ![]() 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 1. The first plesiosaurian genus, the eponymous Plesiosaurus, was named in 1. Since then, more than a hundred valid species have been described. In the early twenty- first century, the number of discoveries has increased, leading to an improved understanding of their anatomy, relationships and way of life. Plesiosaurs had a broad flat body and a short tail. Their limbs had evolved into four long flippers, which were powered by strong muscles attached to wide bony plates formed by the shoulder girdle and the pelvis. The flippers made a flying movement through the water. Plesiosaurs breathed air, and bore live young; there are indications that they were warm- blooded. Plesiosaurs showed two main morphological types. Some species, with the . Other species, some of them reaching a length of up to seventeen metres, had the . The two types are related to the traditional strict division of the Plesiosauria into two suborders, the long- necked Plesiosauroidea and the short- neck Pliosauroidea. Modern research, however, indicates that several . Therefore, the purely descriptive terms . In 1. 60. 5, Richard Verstegen of Antwerp illustrated in his A Restitution of Decayed Intelligence plesiosaur vertebrae that he referred to fishes and saw as proof that Great Britain was once connected to the European continent. The stone plate came from a quarry at Fulbeck and had been used, with the fossil at its underside, to reinforce the slope of a watering- hole in Elston. After the strange bones it contained had been discovered, it was displayed in the local vicarage as the remains of a sinner drowned in the Great Flood. ![]() ![]() Stukely affirmed its . It is the earliest discovered more or less complete fossil reptile skeleton in a museum collection. It can perhaps be referred to Plesiosaurus dolichodeirus. Dinotopia is a fictional utopia created by author and illustrator and Oracle Specialist James Gurney. It is the setting for the book series with which it shares its name. The Plesiosauria (/ Information on the plesiosaurus including pictures, facts, and a short biography. Information about the pterosaur Dsungaripterus and other prehistoric creatures. The Kronosaurus was a large marine reptile that was in existence in the Cretaceous period. It was present on the earth about 123 to 98 million years ago. Dinosaur glossary explains basic paleontological terms, Cr to Cy. Information about Megapiranha (an actual giant piranha that existed during the Miocene) and other prehistoric creatures. Evidence Liopleurodon is a relatively common and well preserved fossil from several marine deposits throughout Europe. It was a type of pliosaur, or short-necked. Welcome to plesiosauria.com Your online resource for everything 'plesiosaur'. The Mesozoic Era was the age of the reptiles. During this time, dinosaurs. Cryptoclidus Cryptoclidus were not dinosaurs. They were from the plesiosauria group which consisted of many marine reptiles. ![]() Important collectors were the reverends William Mounsey and Baptist Noel Turner, active in the Vale of Belvoir, whose collections were in 1. John Nicholls in the first part of his The History and Antiquities of the County of Leicestershire. No systematic distinction was made with ichthyosaurs, so the fossils of one group were sometimes combined with those of the other to obtain a more complete specimen. In 1. 82. 1, a partial skeleton discovered in the collection of Colonel Thomas James Birch. A new genus was named, Plesiosaurus. The generic name was derived from the Greek . Parts of the specimen are still present in the Oxford University Museum of Natural History. In 1. 82. 3, Thomas Clark reported an almost complete skull, probably belonging to Thalassiodracon, which is now preserved by the British Geological Survey as specimen BGS GSM 2. It was acquired by the Duke of Buckingham, who made it available to the geologist William Buckland. He in turn let it be described by Conybeare on 2. February 1. 82. 4 in a lecture to the Geological Society of London. The two finds revealed the unique and bizarre build of the animals, in 1. Professor Buckland likened to . In 1. 82. 4, Conybeare also provided a specific name to Plesiosaurus: dolichodeirus, meaning . In 1. 84. 8, the skeleton was bought by the British Museum of Natural History and catalogued as specimen BMNH 2. This was a short- necked form later assigned to the Pliosauroidea. Hawkins entertained a very idiosyncratic view of the animals, seeing them as monstrous creations of the devil, during a pre- Adamitic phase of history. Sir Richard Owen alone named nearly a hundred new species. The majority of their descriptions were, however, based on isolated bones, without sufficient diagnosis to be able to distinguish them from the other species that had previously been described. Many of the new species described at this time have subsequently been invalidated. The genus Plesiosaurus is particularly problematic, as the majority of the new species were placed in it so that it became a wastebasket taxon. Gradually, other genera were named. Hawkins had already created new genera, though these are no longer seen as valid. In 1. 84. 1, Owen named Pliosaurus brachydeirus. Its etymology referred to the earlier Plesiosaurus dolichodeirus as it is derived from . Its specific name means . The family Plesiosauridae had already been coined by John Edward Gray in 1. While this included some German discoveries, it mainly involved plesiosaurs found in the sediments of the American Cretaceous Western Interior Seaway, the Niobrara Chalk. One fossil in particular marked the start of the Bone Wars between the rival paleontologists Edward Drinker Cope and Othniel Charles Marsh. He soon noticed that the skeleton taking shape under his hands had some very special qualities: the neck vertebrae had chevrons and with the tail vertebrae the joint surfaces were orientated back to front. Having listened to Cope's interpretation for a while, Marsh suggested that a simpler explanation of the strange build would be that Cope had reversed the vertebral column relative to the body as a whole. When Cope reacted indignantly to this suggestion, Leidy silently took the skull and placed it against the presumed last tail vertebra, to which it fitted perfectly: it was in fact the first neck vertebra, with still a piece of the rear skull attached to it. Both Cope and Marsh in their rivalry named many plesiosaur genera and species, most of which are today considered invalid. Around the turn of the century, most plesiosaur research was done by a former student of Marsh, Professor Samuel Wendell Williston. In 1. 91. 4, Williston published his Water reptiles of the past and present. In 2. 01. 3, a first modern textbook was being prepared by Olivier Rieppel. During the middle of the twentieth century, the USA remained an important centre of research, mainly through the discoveries of Samuel Paul Welles. Recent discoveries. The tempo of discovery accelerated in the early twenty- first century, with about three or four plesiosaurs being named each year. Some of this is taking place away from the traditional areas, e. Some of the new genera are a renaming of already known species, which were deemed sufficiently different to warrant a separate genus name. In 2. 00. 2, the . Discovered in 1. 98. Aramberri, in the northern Mexican state of Nuevo Le. The specimen is actually a very large plesiosaur, possibly reaching 1. The media published exaggerated reports claiming it was 2. This error was dramatically perpetuated in BBC's documentary series Walking with Dinosaurs, which also prematurely classified it as a Liopleurodon ferox. In 2. 00. 4, what appeared to be a completely intact juvenile plesiosaur was discovered, by a local fisherman, at Bridgwater Bay National Nature Reserve in Somerset, UK. The fossil, dated 1. Ma by the ammonites associated with it, measured 1. Rhomaleosaurus. It is probably the best preserved specimen of a plesiosaur yet discovered. The new method of cladistics has, for the first time, allowed the exact calculation of their evolutionary relationships. Several hypotheses have been published about the way they hunted and swam, incorporating general modern insights about biomechanics and ecology. The many recent discoveries have tested these hypotheses and given rise to new ones. The increasing scientific interest in the group has been called a . An advanced sauropterygian subgroup, the carnivorous Eusauropterygia with small heads and long necks, split into two branches during the Upper Triassic. One of these, the Nothosauroidea, kept functional elbow and knee joints; but the other, the Pistosauria, became more fully adapted to a sea- dwelling lifestyle. Their vertebral column became stiffer and the main propulsion while swimming no longer came from the tail but from the limbs, which changed into flippers. Their shoulder girdles remained weak, their pelves could not support the power of a strong swimming stroke, and their flippers were blunt. Later, a more advanced pistosaurian group split off: the Plesiosauria. These had reinforced shoulder girdles, flatter pelves, and more pointed flippers. Other adaptations allowing them to colonise the open seas included stiff limb joints; an increase in the number of phalanges of the hand and foot; a tighter lateral connection of the finger and toe phalanx series, and a shortened tail. The subsequent evolution of the plesiosaurs is very contentious. The various cladistic analyses have not resulted in a consensus about the relationships between the main plesiosaurian subgroups. Traditionally, plesiosaurs have been divided into the long- necked plesiosauroidea and the short- necked pliosauroidea. However, modern research suggests that some generally long- necked groups might have had short- necked members. To avoid confusion between the phylogeny, the evolutionary relationships, and the morphology, the way the animal is built, long- necked forms are therefore called . During the earliest Jurassic, the subgroup with the most species was the Rhomaleosauridae, a possibly very basal split- off of species which were also short- necked. Plesiosaurs in this period were at most five metres (sixteen feet) long. By the Toarcian, about 1. Plesiosauridae, became more numerous and some species developed longer necks, resulting in total body lengths of up to ten metres (3. These were characterized by a large head and a short neck, such as Liopleurodon and Simolestes. These forms had skulls up to three metres (ten feet) long and reached a length of up to seventeen metres (5. The pliosaurids had large, conical teeth and were the dominant marine carnivores of their time. During the same time, approximately 1. Cryptoclididae were present, shorter species with a long neck and a small head. The Leptocleididae radiated during the Early Cretaceous.
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