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70-660: The Plesiosauria or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles , belonging to the Sauropterygia . Plesiosaurs first appeared in the latest Triassic 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

140-461: A cohors (plural cohortes ). Some of the plant families still retain the names of Linnaean "natural orders" or even the names of pre-Linnaean natural groups recognized by Linnaeus as orders in his natural classification (e.g. Palmae or Labiatae ). Such names are known as descriptive family names. In the field of zoology , the Linnaean orders were used more consistently. That is,

210-580: A pre-Adamitic phase of history. Hawkins eventually sold his valuable and attractively restored specimens to the British Museum of Natural History. During the first half of the nineteenth century, the number of plesiosaur finds steadily increased, especially through discoveries in the sea cliffs of Lyme Regis. 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

280-509: A capital letter. For some groups of organisms, their orders may follow consistent naming schemes . Orders of plants , fungi , and algae use the suffix -ales (e.g. Dictyotales ). Orders of birds and fishes use the Latin suffix -iformes meaning 'having the form of' (e.g. Passeriformes ), but orders of mammals and invertebrates are not so consistent (e.g. Artiodactyla , Actiniaria , Primates ). For some clades covered by

350-655: A day spa and renamed Eden Hall." Elston Hall was "the home of the Darwin family from 1680 until just after the Second World War , when the estate was sold. Its premier resident was the savant Erasmus Darwin , grandfather of Charles Darwin . Erasmus founded the Lunar Society , which included Josiah Wedgwood , Matthew Boulton , James Watt , Joseph Priestley and Benjamin Franklin ." The present house

420-570: A distinct rank of biological classification having its own distinctive name (and not just called a higher genus ( genus summum )) was first introduced by the German botanist Augustus Quirinus Rivinus in his classification of plants that appeared in a series of treatises in the 1690s. Carl Linnaeus was the first to apply it consistently to the division of all three kingdoms of nature (then minerals , plants , and animals ) in his Systema Naturae (1735, 1st. Ed.). For plants, Linnaeus' orders in

490-537: A few (very) basal forms have been discovered, the most derived Rhaeticosaurus . 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

560-539: A large skeleton of a plesiosaur was found in the continent of Antarctica, the oldest creature on the continent, and the first of its species in Antarctica. Not only has the number of field discoveries increased, but also, since the 1950s, plesiosaurs have been the subject of more extensive theoretical work. The methodology of cladistics has, for the first time, allowed the exact calculation of their evolutionary relationships. Several hypotheses have been published about

630-528: A length of up to seventeen metres, had the "pliosauromorph" build with a short neck and a large head; these were apex predators , fast hunters of large prey. 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 "long-necked" groups might have had some short-necked members or vice versa. Therefore,

700-446: A new clade Neoplesiosauria, a node-based taxon that was defined by as " Plesiosaurus dolichodeirus , Pliosaurus brachydeirus , their most recent common ancestor and all of its descendants". The clade Neoplesiosauria very likely is materially identical to Plesiosauria sensu Druckenmiller & Russell, thus would designate exactly the same species, and the term was meant to be a replacement of this concept. Benson et al. (2012) found

770-481: A plesiosaur skeleton, which he donated to Cope. Cope attempted to reconstruct the animal on the assumption that the longer extremity of the vertebral column was the tail, the shorter one the neck. 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. Excited, Cope concluded to have discovered an entirely new group of reptiles:

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840-524: A plesiosaurian nature and are today partly preserved in the Sedgwick Museum . In 1719, William Stukeley described a partial skeleton of a plesiosaur, which had been brought to his attention by the great-grandfather of Charles Darwin , Robert Darwin of Elston . The stone plate came from a quarry at Fulbeck in Lincolnshire and had been used, with the fossil at its underside, to reinforce

910-686: A rather small short-necked form. 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 180 million years ago, other groups, among them the Plesiosauridae , became more numerous and some species developed longer necks, resulting in total body lengths of up to ten metres (33 feet). In

980-449: 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. Mortified, Cope tried to destroy

1050-458: Is NHMUK PV R.1330 (formerly BMNH R.1330). It is the earliest discovered more or less complete fossil reptile skeleton in a museum collection. It can perhaps be referred to Plesiosaurus dolichodeirus . During the eighteenth century, the number of English plesiosaur discoveries rapidly increased, although these were all of a more or less fragmentary nature. Important collectors were the reverends William Mounsey and Baptist Noel Turner , active in

1120-401: Is a Grade I listed building containing a fine Norman south doorway with zigzag decoration. Inside are layers of wall paintings. It is thought it may have been the chapel of a medieval leper hospital dedicated to St Leonard . Maps show windmills on the north side of Elston Lane ( grid reference SK756487 ) and south side of Mill Lane ( grid reference SK760477 ). The latter was

1190-408: Is called a " stem clade ". Such a definition has the advantage that it is easier to include all species with a certain morphology . Plesiosauria was in 2010 by Hillary Ketchum and Roger Benson defined as such a stem-based taxon : "all taxa more closely related to Plesiosaurus dolichodeirus and Pliosaurus brachydeirus than to Augustasaurus hagdorni ". Ketchum and Benson (2010) also coined

1260-461: Is currently on display at the geological museum of South Dakota School of Mines and Technology . In 2008, fossil remains of an undescribed plesiosaur that was named Predator X , now known as Pliosaurus funkei , were unearthed in Svalbard . It had a length of 12 m (39 ft), and its bite force of 149 kilonewtons (33,000 lb f ) is one of the most powerful known. In December 2017,

1330-419: Is determined by a taxonomist , as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with

1400-588: Is today called the Jurassic Coast . 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 20 February 1824 in a paper read at the Geological Society of London , during the same meeting in which for the first time a dinosaur was named, Megalosaurus . The two finds revealed the unique and bizarre build of

1470-528: The International Code of Zoological Nomenclature , several additional classifications are sometimes used, although not all of these are officially recognized. In their 1997 classification of mammals , McKenna and Bell used two extra levels between superorder and order: grandorder and mirorder . Michael Novacek (1986) inserted them at the same position. Michael Benton (2005) inserted them between superorder and magnorder instead. This position

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1540-648: The Polycotylidae , which had short necks and peculiarly elongated heads with narrow snouts. During the Late Cretaceous, the elasmosaurids still had many species. All plesiosaurs became extinct as a result of the K-T event at the end of the Cretaceous period, approximately 66 million years ago. In modern phylogeny , clades are defined groups that contain all species belonging to a certain branch of

1610-474: The Streptosauria or "Turned Saurians", which would be distinguished by reversed vertebrae and a lack of hindlimbs, the tail providing the main propulsion. After having published a description of this animal, followed by an illustration in a textbook about reptiles and amphibians, Cope invited Marsh and Joseph Leidy to admire his new Elasmosaurus platyurus . Having listened to Cope's interpretation for

1680-815: The Systema Naturae and the Species Plantarum were strictly artificial, introduced to subdivide the artificial classes into more comprehensible smaller groups. When the word ordo was first consistently used for natural units of plants, in 19th-century works such as the Prodromus Systematis Naturalis Regni Vegetabilis of Augustin Pyramus de Candolle and the Genera Plantarum of Bentham & Hooker, it indicated taxa that are now given

1750-634: 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. The Pistosauria became warm-blooded and viviparous , giving birth to live young. Early, basal , members of

1820-568: The Vale of Belvoir , whose collections were in 1795 described by John Nicholls in the first part of his The History and Antiquities of the County of Leicestershire . One of Turner's partial plesiosaur skeletons is still preserved as specimen NHMUK PV R.45 (formerly BMNH R.45) in the British Museum of Natural History; this is today referred to Thalassiodracon . In the early nineteenth century, plesiosaurs were still poorly known and their special build

1890-401: The phylogeny , the evolutionary relationships, and the morphology , the way the animal is built, long-necked forms are therefore called "plesiosauromorph" and short-necked forms are called "pliosauromorph", without the "plesiosauromorph" species necessarily being more closely related to each other than to the "pliosauromorph" forms. The latest common ancestor of the Plesiosauria was probably

1960-571: The 1990s near Herschel, Saskatchewan were found to be a new species, by Dr. Tamaki Sato, a Japanese vertebrate paleontologist. In 2006, a combined team of American and Argentinian investigators (the latter from the Argentinian Antarctic Institute and the La Plata Museum ) found the skeleton of a juvenile plesiosaur measuring 1.5 metres (4 ft 11 in) in length on Vega Island in Antarctica. The fossil

2030-527: The Hall and vicarage, both occupying delightful situations, and built in elegant and stately style. All Saints' Church, Elston has been handsomely restored, and is singularly rich in its memorials of the Darwins. This eminent family appear to have come to Elston from Lincolnshire towards the close of the seventeenth century, the manor being brought into the possession of William Darwin through his marriage with

2100-806: The Sauria" or "near reptile" than as "near lizard". Parts of the specimen are still present in the Oxford University Museum of Natural History . Soon afterwards, the morphology became much better known. In 1823, Thomas Clark reported an almost complete skull, probably belonging to Thalassiodracon , which is now preserved by the British Geological Survey as specimen BGS GSM 26035. The same year, commercial fossil collector Mary Anning and her family uncovered an almost complete skeleton at Lyme Regis in Dorset , England, on what

2170-439: The animals, in 1832 by Professor Buckland likened to "a sea serpent run through a turtle". In 1824, Conybeare also provided a specific name to Plesiosaurus : dolichodeirus , meaning "longneck". In 1848, the skeleton was bought by the British Museum of Natural History and catalogued as specimen NHMUK OR 22656 (formerly BMNH 22656). When the lecture was published, Conybeare also named a second species: Plesiosaurus giganteus . This

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2240-463: The clades Ichthyosauria and Mosasauria , the genera in Plesiosauria are not part of the clade Dinosauria . Skeletal elements of plesiosaurs are among the first fossils of extinct reptiles recognised as such. In 1605, 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

2310-530: The earlier Plesiosaurus dolichodeirus as it is derived from πλεῖος, pleios , "more fully", reflecting that according to Owen it was closer to the Sauria than Plesiosaurus . Its specific name means "with a short neck". Later, the Pliosauridae were recognised as having a morphology fundamentally different from the plesiosaurids. The family Plesiosauridae had already been coined by John Edward Gray in 1825. In 1835, Henri Marie Ducrotay de Blainville named

2380-458: The early twenty-first century, with about three or four plesiosaurs being named each year. This implies that about half of the known plesiosaurs are relatively new to science, a result of a far more intense field research. Some of this is taking place away from the traditional areas, e.g. in new sites developed in New Zealand , Argentina , Chile , Norway , Japan , China and Morocco , but

2450-485: 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,

2520-576: The entire edition of the textbook and, when this failed, immediately published an improved edition with a correct illustration but an identical date of publication. He excused his mistake by claiming that he had been misled by Leidy himself, who, describing a specimen of Cimoliasaurus , had also reversed the vertebral column. Marsh later claimed that the affair was the cause of his rivalry with Cope: "he has since been my bitter enemy". Both Cope and Marsh in their rivalry named many plesiosaur genera and species, most of which are today considered invalid. Around

2590-458: The eponymous Plesiosaurus , was named in 1821. 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

2660-462: The evolutionary tree . One way to define a clade is to let it consist of the last common ancestor of two such species and all its descendants. Such a clade is called a " node clade ". In 2008, Patrick Druckenmiller and Anthony Russell in this way defined Plesiosauria as the group consisting of the last common ancestor of Plesiosaurus dolichocheirus and Peloneustes philarchus and all its descendants. Plesiosaurus and Peloneustes represented

2730-423: The group, traditionally called " pistosaurids ", were still largely coastal animals. 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

2800-403: The heiress of Robert Waring of Wilford. William had two sons, and Elston was left to Robert, the younger, in whom the taste for scientific research began to develop." Elston "currently has about 650 residents in 280 households. A number of new homes have been built within the last twenty years on once open spaces and there continues to be infill development on some of the large gardens." Elston

2870-493: The locations of the more original discoveries have proven to be still productive, with important new finds in England and Germany. Some of the new genera are a renaming of already known species, which were deemed sufficiently different to warrant a separate genus name. In 2002, the " Monster of Aramberri " was announced to the press. Discovered in 1982 at the village of Aramberri , in the northern Mexican state of Nuevo León , it

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2940-527: The longest plesiosaurs, reaching up to fifteen metres (fifty feet) in length due to very long necks containing as many as 76 vertebrae, more than any other known vertebrate. Pliosauridae were still present as is shown by large predators, such as Kronosaurus . At the beginning of the Late Cretaceous , the Ichthyosauria became extinct; perhaps a plesiosaur group evolved to fill their niches:

3010-533: The main subgroups of the Plesiosauroidea and the Pliosauroidea and were chosen for historical reasons; any other species from these groups would have sufficed. Another way to define a clade is to let it consist of all species more closely related to a certain species that one in any case wishes to include in the clade than to another species that one to the contrary desires to exclude. Such a clade

3080-468: The middle of the Jurassic, very large Pliosauridae evolved. 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 (56 feet) and a weight of ten tonnes. The pliosaurids had large, conical teeth and were the dominant marine carnivores of their time. During

3150-482: The middle of the twentieth century, the USA remained an important centre of research, mainly through the discoveries of Samuel Paul Welles . Whereas during the nineteenth and most of the twentieth century, new plesiosaurs were described at a rate of three or four novel genera each decade, the pace suddenly picked up in the 1990s, with seventeen plesiosaurs being discovered in this period. The tempo of discovery accelerated in

3220-526: 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. From the earliest Jurassic , the Hettangian stage, a rich radiation of plesiosaurs is known, implying that the group must already have diversified in the Late Triassic ; of this diversification, however, only

3290-800: The order Plesiosauria itself. In the second half of the nineteenth century, important finds were made outside of England. 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 . In 1867, physician Theophilus Turner near Fort Wallace in Kansas uncovered

3360-708: The orders in the zoology part of the Systema Naturae refer to natural groups. Some of his ordinal names are still in use, e.g. Lepidoptera (moths and butterflies) and Diptera (flies, mosquitoes, midges, and gnats). In virology , the International Committee on Taxonomy of Viruses 's virus classification includes fifteen taxomomic ranks to be applied for viruses , viroids and satellite nucleic acids : realm , subrealm , kingdom , subkingdom, phylum , subphylum , class, subclass, order, suborder, family, subfamily , genus, subgenus , and species. There are currently fourteen viral orders, each ending in

3430-481: 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 1841, Owen named Pliosaurus brachydeirus . Its etymology referred to

3500-564: The precursor of the currently used International Code of Nomenclature for algae, fungi, and plants . In the first international Rules of botanical nomenclature from the International Botanical Congress of 1905, the word family ( familia ) was assigned to the rank indicated by the French famille , while order ( ordo ) was reserved for a higher rank, for what in the 19th century had often been named

3570-442: The purely descriptive terms "plesiosauromorph" and "pliosauromorph" have been introduced, which do not imply a direct relationship. "Plesiosauroidea" and "Pliosauroidea" today have a more limited meaning. The term "plesiosaur" is properly used to refer to the Plesiosauria as a whole, but informally it is sometimes meant to indicate only the long-necked forms, the old Plesiosauroidea. Like other ancient marine reptiles, such as those in

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3640-502: The rank of family (see ordo naturalis , ' natural order '). In French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille (plural: familles ) was used as a French equivalent for this Latin ordo . This equivalence was explicitly stated in the Alphonse Pyramus de Candolle 's Lois de la nomenclature botanique (1868),

3710-816: The same time, approximately 160 million years ago, the Cryptoclididae were present, shorter species with a long neck and a small head. The Leptocleididae radiated during the Early Cretaceous . These were rather small forms that, despite their short necks, might have been more closely related to the Plesiosauridae than to the Pliosauridae. Later in the Early Cretaceous, the Elasmosauridae appeared; these were among

3780-438: 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 "plesiosauromorph" build, had (sometimes extremely) long necks and small heads; these were relatively slow and caught small sea animals. Other species, some of them reaching

3850-678: The slope of a watering-hole in Elston in Nottinghamshire . 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 " diluvial " nature but understood it represented some sea creature, perhaps a crocodile or dolphin. The specimen is today on display at the Natural History Museum , and its inventory number

3920-523: The suffix -virales . Elston Elston is a village and civil parish in the Newark and Sherwood district, in Nottinghamshire , England, to the south-west of Newark , 0.5 mi (800 m) from the A46 Fosse Way . The population of the civil parish taken at the 2011 census was 631, increasing to 697 at the 2021 census . It lies between the rivers Trent and Devon , with

3990-633: The traditional Pliosauroidea to be paraphyletic in relation to Plesiosauroidea. Rhomaleosauridae was found to be outside Neoplesiosauria, but still within Plesiosauria. The early Carnian pistosaur Bobosaurus was found to be one step more advanced than Augustasaurus in relation to the Plesiosauria and therefore it represented by definition the basalmost known plesiosaur. This analysis focused on basal plesiosaurs and therefore only one derived pliosaurid and one cryptoclidian were included, while elasmosaurids were not included at all. A more detailed analysis published by both Benson and Druckenmiller in 2014

4060-403: The turn of the century, most plesiosaur research was done by a former student of Marsh, Professor Samuel Wendell Williston . In 1914, Williston published his Water reptiles of the past and present . Despite treating sea reptiles in general, it would for many years remain the most extensive general text on plesiosaurs. In 2013, a first modern textbook was being prepared by Olivier Rieppel . During

4130-458: The village "set amongst trees and farmland less than a mile from the A46 .... Newark is five miles to the north, with... Lincoln and Nottingham some 18 miles north and south-west respectively." According to Cornelius Brown's 1896 History of Nottinghamshire , the village lies "very snugly and prettily ensconced in the midst of a pleasing landscape of North England. Nearly opposite each other are

4200-460: 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 Plesiosauria have their origins within the Sauropterygia , a group of perhaps archelosaurian reptiles that returned to the sea. An advanced sauropterygian subgroup, the carnivorous Eusauropterygia with small heads and long necks, split into two branches during

4270-750: Was "founded by the Angles in the 5th century. Its square shape is typically Anglo Saxon . The name derives from a leader named Elva and appears in the Domesday book as Elvastun. Historic old buildings in and adjacent to the parish include Elston Hall, All Saints Church, the Old Chapel of Ease on the site of a mediaeval leper hospital, the Methodist Chapel, and Elston Towers, the Victorian mansion of preacher Robert Middleton , now refurbished as

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4340-546: Was a short-necked form later assigned to the Pliosauroidea . Plesiosaurs became better known to the general public through two lavishly illustrated publications by the collector Thomas Hawkins : Memoirs of Ichthyosauri and Plesiosauri of 1834 and The Book of the Great Sea-Dragons of 1840. Hawkins entertained a very idiosyncratic view of the animals, seeing them as monstrous creations of the devil, during

4410-418: Was adopted by Systema Naturae 2000 and others. In botany , the ranks of subclass and suborder are secondary ranks pre-defined as respectively above and below the rank of order. Any number of further ranks can be used as long as they are clearly defined. The superorder rank is commonly used, with the ending -anae that was initiated by Armen Takhtajan 's publications from 1966 onwards. The order as

4480-507: Was begun in 1756, then extended in 1837 and again later that century and in the 1950s. Originally H-shaped, it is now a linear sequence of two-storey ranges, the earliest being the central range built in blue lias stone. Grade II listed in 1952, the buildings are now divided into ten residences. Once a parish church , this was declared redundant in 1976, and under the care of the Churches Conservation Trust . It

4550-523: Was discovered, by a local fisherman, at Bridgwater Bay National Nature Reserve in Somerset, UK. The fossil, dating from 180 million years ago as indicated by the ammonites associated with it, measured 1.5 metres (4 ft 11 in) in length, and may be related to Rhomaleosaurus . It is probably the best preserved specimen of a plesiosaur yet discovered. In 2005, the remains of three plesiosaurs ( Dolichorhynchops herschelensis ) discovered in

4620-618: Was named, Plesiosaurus . The generic name was derived from the Greek πλήσιος, plèsios , "closer to" and the Latinised saurus , in the meaning of "saurian", to express that Plesiosaurus was in the Chain of Being more closely positioned to the Sauria , particularly the crocodile, than Ichthyosaurus , which had the form of a more lowly fish. The name should thus be rather read as "approaching

4690-588: Was not able to resolve the relationships among the lineages at the base of Plesiosauria. The following cladogram follows an analysis by Benson & Druckenmiller (2014). " Pistosaurus " postcranium Yunguisaurus Augustasaurus Bobosaurus Stratesaurus Eoplesiosaurus Rhomaleosauridae [REDACTED] Thalassiodracon Hauffiosaurus Attenborosaurus [REDACTED] Marmornectes Thalassophonea [REDACTED] Plesiosaurus Eretmosaurus Order (biology) What does and does not belong to each order

4760-410: Was not understood. 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 1821, a partial skeleton discovered in the collection of Colonel Thomas James Birch , was described by William Conybeare and Henry Thomas De la Beche , and recognised as representing a distinctive group. A new genus

4830-468: Was once connected to the European continent. The Welshman Edward Lhuyd in his Lithophylacii Brittannici Ichnographia from 1699 also included depictions of plesiosaur vertebrae that again were considered fish vertebrae or Ichthyospondyli . Other naturalists during the seventeenth century added plesiosaur remains to their collections, such as John Woodward ; these were only much later understood to be of

4900-421: Was originally classified as a dinosaur . The specimen is actually a very large plesiosaur, possibly reaching 15 m (49 ft) in length. The media published exaggerated reports claiming it was 25 metres (82 ft) long, and weighed up to 150,000 kilograms (330,000 lb), which would have made it among the largest predators of all time. In 2004, what appeared to be a completely intact juvenile plesiosaur

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