''Liopleurodon'' (; meaning 'smooth-sided teeth') is an extinct genus of large,

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other ...

marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. The earliest marine reptile mesosaurus (not to be confused with mosasaurus), arose in the Permian period during th ...

belonging to the

Thalassophonea Thalassophonea is an extinct clade of pliosaurids from the Middle Jurassic to the early Late Cretaceous ( Callovian to Turonian) of Australia, Europe, North America and South America. ''Thalassophonea'' was erected by Roger Benson and Patrick ...

, a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

of short-necked

pliosaurid Pliosauridae is a family of plesiosaurian marine reptiles from the Latest Triassic to the early Late Cretaceous (Rhaetian to Turonian stages) of Australia, Europe, North America and South America. The family is more inclusive than the archetypal ...

plesiosaur The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appea ...

s. ''Liopleurodon'' lived from the

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

Stage of the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively ...

to the

Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...

stage of the

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

(c. 166 to 155 mya). It was the

apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...

of the Middle to Late Jurassic seas that covered

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

. The largest species, ''L. ferox'', is estimated to have grown up to in length, but could have been larger. The name "Liopleurodon" (meaning "smooth-sided tooth") derives from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...

words: ', "smooth"; ', "side" or "rib"; and ', "tooth".

Discovery and species

Even before ''Liopleurodon'' was named, material likely belonging to it was described. In 1841,

Hermann von Meyer Christian Erich Hermann von Meyer (3 September 1801 – 2 April 1869), known as Hermann von Meyer, was a German palaeontologist. He was awarded the 1858 Wollaston medal by the Geological Society of London. Life He was born at Frankfurt am Ma ...

named the species ''

Thaumatosaurus ''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 ...

oolithicus'' based on a fragmentary specimen consisting of partial teeth, skull elements, vertebrae, and ribs from deposits in

Württemberg Württemberg ( ; ) is a historical German territory roughly corresponding to the cultural and linguistic region of Swabia. The main town of the region is Stuttgart. Together with Baden and Hohenzollern, two other historical territories, Württ ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...

possibly dating to the Oxfordian. However, this material is nondiagnostic, lacking distinguishing features.

Johann Andreas Wagner Johann Andreas Wagner (21 March 1797 – 17 December 1861) was a German palaeontologist, zoologist and archaeologist who wrote several important works on palaeontology. Career Wagner was a professor at the University of Munich, and curator ...

published a description of a large plesiosaur tooth from

Bavaria Bavaria ( ; ), officially the Free State of Bavaria (german: Freistaat Bayern, link=no ), is a state in the south-east of Germany. With an area of , Bavaria is the largest German state by land area, comprising roughly a fifth of the total l ...

, Germany in 1852, assigning it to a new

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

that he named ''

Pliosaurus ''Pliosaurus'' (meaning 'more lizard') is an extinct genus of thalassophonean pliosaurid known from the Kimmeridgian and Tithonian stages (Late Jurassic) of Europe and South America. Their diet would have included fish, cephalopods, and marine ...

giganteus''. However, in 1824, William Conybeare had named a species of ''

Plesiosaurus ''Plesiosaurus'' (Greek: ' ('), near to + ' ('), lizard) is a genus of extinct, large marine sauropterygian reptile that lived during the Early Jurassic. It is known by nearly complete skeletons from the Lias of England. It is distinguishable b ...

'', ''Plesiosaurus giganteus'', and this species was later viewed as a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are al ...

of either ''Pliosaurus brachydeirus'' or ''P. brachyspondylus'' by following authors. Since the name ''Pliosaurus giganteus'' had been used prior to Wagner's publication, Wagner's name is invalid due to preoccupation. In 1838,

applied the name '' Ischyrodon meriani'' to a large tooth from Oxfordian-aged rocks in Frickthale,

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

. This tooth lacks identifying characteristics, and therefore it is not clear what it belonged to, although Lambert Beverly Tarlo noted the possibility of it pertaining to ''Liopleurodon'' in 1960. A 2022 study by Daniel Madzia and colleagues noted that while the tooth likely came from ''Liopleurodon'' or something similar, there was too little information available to make a confident assignment, so they treated ''Ischyrodon'' as a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

''. In 1860,

Hermann Trautschold , citizenship = German Empire, Russian Empire , nationality = German , field = geology and paleontology , work_institutions = University of GiessenPetrovsky Agricultural and Forestry Academy , alma_mater = University of Giessen , docto ...

assigned the name ''Pliosaurus giganteus'' to a small tooth now thought to pertain to ''Liopleurodon''. However, as the name ''Pliosaurus giganteus'' had already been used twice by this point, Trautschold's name is also invalid. Liopleurodon ferox skull reconstruction

The genus name ''Liopleurodon'' was coined by

Henri Émile Sauvage Henri Émile Sauvage (22 September 1842 in Boulogne-sur-Mer – 3 January 1917 in Boulogne-sur-Mer) was a French paleontologist, ichthyologist, and herpetologist. He was a leading expert on Mesozoic fish and reptiles.crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

measuring long, was found near Boulogne-sur-Mer, France in layers dating from the

, and was named ''Liopleurodon ferox''. Another from Charly, France, measuring long and with a crown length of , was named ''Liopleurodon grossouvrei''. The third, discovered near

Caen, France Caen (, ; nrf, Kaem) is a commune in northwestern France. It is the prefecture of the department of Calvados. The city proper has 105,512 inhabitants (), while its functional urban area has 470,000,Poikilopleuron bucklandi'' by Eudes Deslongchamps. While the tooth could have come from the megalosaur, Sauvage considered this identity unsubstantiated, and assigned it to the species ''Liopleurodon bucklandi''. Sauvage did not ascribe the genus to any particular group of reptiles in his descriptions. However, in 1880, Sauvage synonymized ''Liopleurodon'' with ''

Polyptychodon ''Polyptychodon'' (meaning 'shaped fin tooth') is a genus of pliosaurid found in Middle-Late Cretaceous marine deposits in southern England, France and Argentina. It has been considered a ''nomen dubium'' in a 2016 review. History of discovery ...

'', noting that it was similar to this genus, but distinct from ''Plesiosaurus'' and ''Pliosaurus''. In 1888,

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker ...

, after studying some teeth attributable to ''Liopleurodon ferox'' in the Leeds Collection, concluded that they were so similar to those of ''Pliosaurus'' that they should be placed in that genus. These teeth had been collected by

Alfred Leeds Alfred Nicholson Leeds (9 March 184725 August 1917) was an English amateur palaeontologist. Biography Leeds was born at Eyebury, Peterborough, the youngest of the eight children of Edward Thurlow Leeds (180251) and Eliza Mary Leeds (née Nichols ...

from the Oxford Clay Formation, near

Peterborough Peterborough () is a cathedral city in Cambridgeshire, east of England. It is the largest part of the City of Peterborough unitary authority district (which covers a larger area than Peterborough itself). It was part of Northamptonshire unti ...

, England. In 1869,

Harry Govier Seeley Harry Govier Seeley (18 February 1839 – 8 January 1909) was a British paleontologist. Early life Seeley was born in London on 18 February 1839, the second son of Richard Hovill Seeley, a goldsmith, and his second wife Mary Govier. When his fat ...

had applied the name ''Pliosaurus pachydeirus'' to a series of cervical (neck) vertebrae representing the first 17 in the neck from the Oxford Clay Formation near

Great Gransden Great Gransden is a civil parish and village in the Huntingdonshire district of Cambridgeshire, England. In 2001, the parish population was 969, which rose to 1,023 at the 2011 Census. It lies 16 miles (25 km) west of Cambridge and 13 mil ...

. Other than its large size, Seeley provided no distinguishing characteristics. Lydekker stated that this neck probably belonged to ''Pliosaurus ferox''. W. Kiprijanoff named ''Thaumatosaurus mosquensis'' in 1883 based on remains including teeth, vertebrae, and limb bones from Oxfordian-aged rocks in the

Moscow Basin The Moscow Basin is a major sedimentary basin and tectonic structural feature in the stable East European Craton. It has been widely studied by Russian and Scandinavian geologists. Formation and geological history The Fennoscandia Shield and its ...

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...

; however, in 1889, Lydekker considered this species to be a probable junior synonym of ''P. ferox''. In 1905,

John Frederick Blake John Frederick Blake (3 April 1839 – 7 July 1906) was a British geologist and Anglican clergyman. Blake received B.A. 1862 and M.A. 1865 from Caius College, Cambridge. He was ordained a deacon in 1862 and a priest in 1863. He was curate of Len ...

described two teeth from

Rushden Rushden is a market town and civil parish in North Northamptonshire, England, around east of Northampton. The parish is on the border with Bedfordshire, north of Bedford. The parish of Rushden covers an area of some . The population of Rushd ...

, England similar to those of other ''Liopleurodon ferox'' specimens, though from older strata than those from Peterborough. He noted that the teeth were quite different from those of ''Pliosaurus'', while the bones were dissimilar to those of ''Polyptychodon''. Since the species couldn't be assigned to either genus, he recommended reinstating the name ''Liopleurodon''. After considering ''Liopleurodon'' to be a

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between ...

of ''Pliosaurus'', N. Bogolubov also listed the two genera as distinct in 1912. When Lydekker had first visited the collection of Alfred Leeds (known as the Leeds Collection), the only remains of ''Liopleurodon'' in his collection were teeth. However, since then, Alfred Leeds, as well as his brother Charles Edward Leeds, had collected many more specimens of ''Liopleurodon'', including skulls and much of the postcranial skeleton.

Charles William Andrews Charles William Andrews (30 October 1866 – 25 May 1924) F.R.S., was a British palaeontologist whose career as a vertebrate paleontologist, both as a curator and in the field, was spent in the services of the British Museum, Department of Ge ...

described the anatomy of the

specimens of the Leeds Collection acquired by the

British Museum of Natural History The Natural History Museum in London is a museum that exhibits a vast range of specimens from various segments of natural history. It is one of three major museums on Exhibition Road in South Kensington, the others being the Science Museum ...

in two volumes, the first published in 1910 and the second in 1913. He described the ''Liopleurodon'' specimens in the second volume, though considered them to belong to ''Pliosaurus''. Hermann Linder also described specimens of ''Liopleurodon ferox'' in 1913. One of these was a poorly preserved partial skeleton excavated from the Oxford Clay of Fletton, England, housed in Institut für Geowissenschaften,

University of Tübingen The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-W� ...

. The skeleton was mounted and missing regions were restored with material from other ''Liopleurodon'' specimens. Like Andrews, Linder also considered ''L. ferox'' to be a species of ''Pliosaurus''. Additionally, Linder described some skulls from Fletton housed at both the University of Tübingen and the

State Museum of Natural History Stuttgart The State Museum of Natural History Stuttgart (german: Staatliches Museum für Naturkunde Stuttgart), abbreviated SMNS, is one of the two state of Baden-Württemberg's natural history museums. Together with the State Museum of Natural History ...

as specimens of ''P. grandis''. Linder also assigned a nearly complete paddle to ''Pliosaurus'' sp. All of these specimens have since been assigned to ''Liopleurodon'' with varying degrees of confidence, though the skull Linder attributed to ''P. grandis'' that was housed in Stuttgart was destroyed during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

. In 1934,

Friedrich von Huene Friedrich von Huene, born Friedrich Richard von Hoinigen, (March 22, 1875 – April 4, 1969) was a German paleontologist who renamed more dinosaurs in the early 20th century than anyone else in Europe. He also made key contributions about v ...

described a partial skeleton from

Swabia Swabia ; german: Schwaben , colloquially ''Schwabenland'' or ''Ländle''; archaic English also Suabia or Svebia is a cultural, historic and linguistic region in southwestern Germany. The name is ultimately derived from the medieval Duchy of ...

, Germany. He also used ''Pliosaurus ferox'' instead of ''Liopleurodon ferox''. In 1939, Alexandre Bigot used ''Pliosaurus ferox'' as well, assigning some teeth from France to this species. Lambert Beverly Halstead, then known as Tarlo, published a review of Upper Jurassic pliosaurid taxonomy in 1960. He considered ''Liopleurodon'' to be distinct from ''Pliosaurus'', noting major differences between the mandibles of the two genera. In addition to the type species ''L. ferox'', Tarlo also considered ''Pliosaurus pachydeirus'' to be a valid species within ''Liopleurodon'', ''L. pachydeirus'', noting that the two species had differences in their teeth and cervical vertebrae. ''L. grossouvrei'' was not considered valid, though it was tentatively retained for teeth from the Kellaways Formation. In 1971, Halstead published another paper about Jurassic pliosaurids, this time focusing on ''Pliosaurus rossicus'', a species he was formerly unwilling to consider valid, due to a lack of information. After reviewing its anatomy, he considered it valid, though assigned it to ''Liopleurodon'' instead, based on its short mandibular symphysis. Halstead also considered ''Pliosaurus macromerus'', which he had previously considered to belong to its own genus, ''Stretosaurus'', to instead be a species of ''Liopleurodon'', despite its irregularly-shaped

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eith ...

(although this was later discovered to be an ilium). In a 2001 dissertation, Leslie F. Noè argued that ''L. pachydeirus'' was not diagnostic, and that ''L. ferox'' was the only valid species of ''Liopleurodon''. The teeth of mounted skeleton in Tübingen, which Tarlo had attributed to ''L. pachydeirus'', showed distinctive characteristics of ''L. ferox'', indicating that cervical vertebrae are not useful for differentiating species, as argued by David S. Brown in 1981. While Tarlo had considered differences in tooth morphology to be diagnostic, Noè instead considered it to be individual variation. Noè also removed ''L. macromerus'' and ''L. rossicus'' from the genus, citing differences in tooth shape and mandibular symphysis length. The former species was tentatively placed back in ''Pliosaurus'', while the latter was thought to warrant a new genus. ''Liopleurodon'' fossils have been found mainly in

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...

and France. Fossil specimens that are contemporary (Callovian-Kimmeridgian) with those from England and France referrable to ''Liopleurodon'' are known from

.Sachs, S. (1997). "Mesozoische Reptilien aus Nordrhein-Westfalen." Pp. 22-27 in Sachs, S., Rauhut, O.W.M. and Weigert, A. (eds.), ''Terra Nostra. 1. Treffen der deutschsprachigen Paläoherpetologen Düsseldorf''. In 2013, Roger Benson and colleagues considered both ''"L." macromerus'' and ''"L." rossicus'' to belong to ''Pliosaurus''. They also considered ''Liopleurodon'' to be restricted to the Middle Jurassic. In 2015, Jair Israel Barrientos-Lara and colleagues described two pliosaurid fossils found near the town of

Tlaxiaco Tlaxiaco is a city, and its surrounding municipality of the same name, in the Mexican state of Oaxaca. It is located in the Tlaxiaco District in the south of the Mixteca Region, with a population of about 17,450. The city is formally known as He ...

Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the Federative Entities of Mexico. It is divided into 570 municipaliti ...

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

. These fossils were extracted from Kimmeridgian deposits in the

Sabinal Formation Sabinal may refer to: * Cayo Sabinal, island in Cuba * Rio Sabinal Group, a geologic group in Mexico * Sabinal, Texas Sabinal is a city in Uvalde County, Texas, United States. The population was 1,695 at the 2010 census. Geography Sabinal is ...

, and one of them, the partial front end of a snout, was attributable to ''Liopleurodon'', though the researchers considered the remains too fragmentary to provide a species-level identification. ''Liopleurodon grossouvrei'', although synonymized with ''Pliosaurus andrewsi'' by most authors, was considered to potentially be a distinct genus in its own right by Davide Foffa and colleagues in 2018, given its differences from ''P. andrewsi'' and ''Liopleurodon ferox''. Madzia and colleagues in 2022 noted that the fact that ''Liopleurodon'' was named based on a single tooth of dubious distinctiveness is problematic, and that a more complete

neotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

may need to be designated to preserve the stability of ''L. ferox''. They also stated that further study of the taxon was needed to confirm that the supposed differences between ''L. ferox'' and ''L. pachydeirus'' were indeed due to individual variation.

Description

Size

''Liopleurodon ferox'' first came to the public attention in 1999 when it was featured in an episode of the BBC television series ''

Walking with Dinosaurs ''Walking with Dinosaurs'' is a 1999 six-part nature documentary television miniseries created by Tim Haines and produced by the BBC Science Unit the Discovery Channel and BBC Worldwide, in association with TV Asahi, ProSieben and France 3. Envi ...

'', which depicted it as an enormous long and predator; this was based on very fragmentary remains, and considered to be an exaggeration for ''Liopleurodon'', with the calculations of 20-metre specimens generally considered dubious. Estimating the size of pliosaurs is difficult because not much is known of their postcranial anatomy. The palaeontologist L. B. Tarlo suggested that their total body length can be estimated from the length of their skull which he claimed was typically one-seventh of the former measurement, applying this ratio to ''L. ferox'' suggests that the largest known specimen was a little over while a more typical size range would be from . The body mass has been estimated at for the lengths respectively. Additional ''

Kronosaurus ''Kronosaurus'' ( ; meaning "lizard of Kronos") is a potentially dubious genus of extinct short-necked pliosaur. With an estimated length of , it was among the largest pliosaurs, and is named after the leader of the Greek Titans, Kronos. It ...

'' specimens and a skeleton of ''L. ferox'', GPIT 1754/2, show that their skulls were actually about one-fifth of their total body length. One specimen, CAMSMJ.27424, has an estimated total length of . The largest known skull, NHM R3536, reached in condylobasal length ( in overall length). In 2022, Gregory S. Paul suggested that a long ''L. ferox'' would have weighed in body mass.

Classification

''Liopleurodon'' belongs to clade

, a short necked clade within the

Pliosauridae Pliosauridae is a family of plesiosaurian marine reptiles from the Latest Triassic to the early Late Cretaceous (Rhaetian to Turonian stages) of Australia, Europe, North America and South America. The family is more inclusive than the archetypal ...

, a family of

plesiosaurs The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared i ...

, thalassophoneans ranged from the Middle Jurassic to early Late Cretaceous, and have been found worldwide. ''Liopleurodon'' was one of the basal taxa from the Middle Jurassic. Differences between these taxa and their relatives from the Upper Jurassic include

alveoli Alveolus (; pl. alveoli, adj. alveolar) is a general anatomical term for a concave cavity or pit. Uses in anatomy and zoology * Pulmonary alveolus, an air sac in the lungs ** Alveolar cell or pneumocyte ** Alveolar duct ** Alveolar macrophage * M ...

count, smaller skull and smaller body size. An analysis in 2013 classifies ''Liopleurodon'', ''

Simolestes ''Simolestes'' (meaning "hearkening thief") is an extinct pliosaurid genus that lived in the Middle to Late Jurassic. The type specimen, BMNH R. 3319 is an almost complete but crushed skeleton diagnostic to ''Simolestes vorax'', dating back to ...

'', ''

Peloneustes ''Peloneustes'' (meaning "mud swimmer") is a genus of pliosaurid plesiosaur from the Middle Jurassic of England. Its remains are known from the Peterborough Member of the Oxford Clay Formation, which is Callovian in age. It was originally descr ...

'', ''

'', '' Gallardosaurus'', and

Brachaucheninae Thalassophonea is an extinct clade of pliosaurids from the Middle Jurassic to the early Late Cretaceous (Callovian to Turonian) of Australia, Europe, North America and South America. ''Thalassophonea'' was erected by Roger Benson and Pat ...

. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

below follows a 2011 analysis by paleontologists Hilary F. Ketchum and Roger B. J. Benson, and reduced to genera only.

Palaeobiology

Four strong paddle-like limbs suggest that ''Liopleurodon'' was a powerful swimmer. Its four-flipper mode of propulsion is characteristic of all plesiosaurs. A study involving a swimming robot has demonstrated that although this form of propulsion is not especially efficient, it provides very good acceleration—a desirable trait in an ambush predator. Studies of the skull have shown that it could probably scan the water with its nostrils to ascertain the source of certain smells.Carpenter, K. (1997). "Comparative cranial anatomy of two North American Cretaceous plesiosaurs." Pp. 191–216 in Callaway, J.M. and Nicholls, E.L. (eds.), ''Ancient Marine Reptiles''. Academic Press.

References

External links

''Liopleurodon'' information and photos
The Plesiosaur Directory
Article on the giant pliosaur skull once assigned to ''Liopleurodon''
Tetrapod Zoology {{Taxonbar, from=Q287975 Pliosaurids Middle Jurassic plesiosaurs of Europe Late Jurassic plesiosaurs of Europe Fossil taxa described in 1873 Taxa named by Henri Émile Sauvage Oxford Clay Sauropterygian genera