Liopleurodon
Encyclopedia
Liopleurodon is a genus of large, carnivorous
marine reptile
belonging to the Pliosaur
oidea, a clade
of short-necked plesiosaur
s. Two species of Liopleurodon lived during the Callovian
stage of the Middle Jurassic
Period (c. 160 to 155 mya), while the third, L. rossicus, lived during the Late Jurassic. It was the apex predator
of the Middle to Late Jurassic seas that covered Europe
. The largest species, L. ferox, is estimated to have grown up to 6.39 metres (21 ft) in length.
in 1873 on the basis of very poor remains consisting of three 70 millimeter teeth. One tooth, found near Boulogne-sur-Mer, France
in layers dating from the Callovian
, was named Liopleurodon ferox, another from Charly, France was named Liopleurodon grossouvrei, while a third discovered near Caen, France
was originally described as Poikilopleuron bucklandi and ascribed by Sauvage to the species Liopleurodon bucklandi. Sauvage did not ascribe the genus to any particular group of reptiles in his descriptions.
Liopleurodon fossils have been found mainly in England
and France, with one younger species known from Russia
. Fossil specimens that are contemporary (Callovian) with those from England and France referrable to Liopleurodon are known from Germany
.
Currently, there are three recognized species within Liopleurodon. From the Callovian of England and France L. ferox is well known; while also from the Callovian of England is the rarer L. pachydeirus, described by Seeley as a Pliosaurus (1869). L. rossicus is known from the early Tithonian
(Volga Beds) of Russia. This species was initially described by Novozhilov (in 1948) as belonging to Pliosaurus, and is the type species of the genus Strongylokroptaphus. Only L. ferox is known from more or less complete skeletons.
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.
exposed some uncertainty about the accuracy of Tarlo's suggestion.
New research on pliosaur anatomy has cast doubt on Tarlo's hypothesis for estimating the size of pliosaurs and revealed that pliosaur skulls were typically about one-fifth of the total body length. An exceptionally well-preserved skeleton of L. ferox is on display in the Institut und Museum für Geologie und Paläontologie der Universität Tübingen in Germany. This specimen is around 4.5 metres (14.8 ft) long.
Fossil remains of another specimen identified as L. ferox have been excavated from an Oxford Clay
formation near Peterborough
. This specimen has been estimated to be 6.39 metres (21 ft) in length with a skull length of about 1.26 metres (4.1 ft) and is regarded as an adult individual. An adult L. ferox would have averaged 5–7 m (16.4–23 ft) long.
Some fossil remains excavated from the Kimmeridge Clay
formation in England
indicate a much larger taxon, possibly up to 15 metres (49.2 ft) long. However, these have not been assigned to the Liopleurodon genus.
A partial specimen of a jaw mandible measuring 2.875 metres (9.4 ft) is on display in the Oxford University Museum of Natural History
: it is estimated that the total length of the jaw is in excess of 3 metres (9.8 ft). The specimen was originally assigned to the Stretosaurus genus (as Stretosaurus macromerus), but is currently believed to belong to the Liopleurodon genus and has been renamed L. macromerus. The genus Stretosaurus later became a junior synonym
of Liopleurodon. However, it has been re-classified as Pliosaurus macromerus
.
In 1999, Liopleurodon was featured in an episode the BBC
television series Walking with Dinosaurs
, which depicted it as an enormous 25 metre-long animal. However, this is not considered to be accurate for any species of Liopleurodon.
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
marine reptile
Marine reptile
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semi-aquatic life in a marine environment.The earliest marine reptiles arose in the Permian period during the Paleozoic era...
belonging to the Pliosaur
Pliosaur
Pliosauroidea is an extinct clade of marine reptiles. Pliosauroids, also commonly known as pliosaurs, are known from the Jurassic and Cretaceous Periods. The pliosauroids were short-necked plesiosaurs with large heads and massive toothed jaws. These swimming reptiles were not dinosaurs but distant...
oidea, a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of short-necked plesiosaur
Plesiosaur
Plesiosauroidea is an extinct clade of carnivorous plesiosaur marine reptiles. Plesiosauroids, are known from the Jurassic and Cretaceous Periods...
s. Two species of Liopleurodon lived during the Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
stage of the Middle Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
Period (c. 160 to 155 mya), while the third, L. rossicus, lived during the Late Jurassic. It was the apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
of the Middle to Late Jurassic seas that covered Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. The largest species, L. ferox, is estimated to have grown up to 6.39 metres (21 ft) in length.
Discovery and species
The genus name Liopleurodon was coined by Henri Émile SauvageHenri Émile Sauvage
- Works :Articles in The Popular Science Monthly:* “Amphibious Fishes,” in Popular Science Monthly Volume 9, September 1876* “The Archer-Fishes,” in Popular Science Monthly Volume 12, January 1878* “The Matamata,” in Popular Science Monthly Volume 16, March 1880...
in 1873 on the basis of very poor remains consisting of three 70 millimeter teeth. One tooth, found near Boulogne-sur-Mer, France
Boulogne-sur-Mer
-Road:* Metropolitan bus services are operated by the TCRB* Coach services to Calais and Dunkerque* A16 motorway-Rail:* The main railway station is Gare de Boulogne-Ville and located in the south of the city....
in layers dating from the Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
, was named Liopleurodon ferox, another from Charly, France was named Liopleurodon grossouvrei, while a third discovered near Caen, France
Caen
Caen is a commune in northwestern France. It is the prefecture of the Calvados department and the capital of the Basse-Normandie region. It is located inland from the English Channel....
was originally described as Poikilopleuron bucklandi and ascribed by Sauvage to the species Liopleurodon bucklandi. Sauvage did not ascribe the genus to any particular group of reptiles in his descriptions.
Liopleurodon fossils have been found mainly in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
and France, with one younger species known from Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. Fossil specimens that are contemporary (Callovian) with those from England and France referrable to Liopleurodon are known from Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
.
Currently, there are three recognized species within Liopleurodon. From the Callovian of England and France L. ferox is well known; while also from the Callovian of England is the rarer L. pachydeirus, described by Seeley as a Pliosaurus (1869). L. rossicus is known from the early Tithonian
Tithonian
In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...
(Volga Beds) of Russia. This species was initially described by Novozhilov (in 1948) as belonging to Pliosaurus, and is the type species of the genus Strongylokroptaphus. Only L. ferox is known from more or less complete skeletons.
Palaeobiology
Size
Estimating the maximum size of Liopleurodon has become a controversial subject. The palaeontologist L. B. Tarlo suggested that the total body length of a pliosaur (including Liopleurodon) can be estimated from its skull length. Tarlo claimed that the skull of a pliosaur is typically about one-seventh of the total body length. The largest known skull belonging to L. ferox is 1.5 metres (4.9 ft) long. According to Tarlo's hypothesis, this specimen would be around 10.5 metres (34.4 ft) long. However, the case of KronosaurusKronosaurus
Kronosaurus is an extinct genus of short-necked pliosaur. It was among the largest pliosaurs, and is named after the leader of the Greek Titans, Cronus.-Discovery and species:Kronosaurus lived in the Early Cretaceous Period ....
exposed some uncertainty about the accuracy of Tarlo's suggestion.
Fossil remains of another specimen identified as L. ferox have been excavated from an Oxford Clay
Oxford Clay
The Oxford Clay Formation is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay is of middle Callovian to lower Oxfordian age and comprises 2 main facies. The lower facies comprises the...
formation near Peterborough
Peterborough
Peterborough is a cathedral city and unitary authority area in the East of England, with an estimated population of in June 2007. For ceremonial purposes it is in the county of Cambridgeshire. Situated north of London, the city stands on the River Nene which flows into the North Sea...
. This specimen has been estimated to be 6.39 metres (21 ft) in length with a skull length of about 1.26 metres (4.1 ft) and is regarded as an adult individual. An adult L. ferox would have averaged 5–7 m (16.4–23 ft) long.
Some fossil remains excavated from the Kimmeridge Clay
Kimmeridge Clay
The Kimmeridge Clay Formation is a sedimentary deposit of fossiliferous marine clay which is of Jurassic age. It occurs in Europe.Kimmeridge Clay is arguably the most economically important unit of rocks in the whole of Europe, being the major source rock for oil fields in the North Sea hydrocarbon...
formation in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
indicate a much larger taxon, possibly up to 15 metres (49.2 ft) long. However, these have not been assigned to the Liopleurodon genus.
A partial specimen of a jaw mandible measuring 2.875 metres (9.4 ft) is on display in the Oxford University Museum of Natural History
Oxford University Museum of Natural History
The Oxford University Museum of Natural History, sometimes known simply as the Oxford University Museum, is a museum displaying many of the University of Oxford's natural history specimens, located on Parks Road in Oxford, England. It also contains a lecture theatre which is used by the...
: it is estimated that the total length of the jaw is in excess of 3 metres (9.8 ft). The specimen was originally assigned to the Stretosaurus genus (as Stretosaurus macromerus), but is currently believed to belong to the Liopleurodon genus and has been renamed L. macromerus. The genus Stretosaurus later became a junior synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
of Liopleurodon. However, it has been re-classified as Pliosaurus macromerus
Pliosaurus
Pliosaurus is a genus of extinct marine reptile. It is included in the family Pliosauridae. Its diet would have included fish, squid and other marine reptiles. This genus has contained several species in the past but it currently consists of the type species P. brachydeirus, P. macromerus and P...
.
In 1999, Liopleurodon was featured in an episode the BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
television series Walking with Dinosaurs
Walking with Dinosaurs
Walking with Dinosaurs is a six-part documentary television miniseries that was produced by BBC, narrated by Kenneth Branagh, and first aired in the United Kingdom, in 1999. The series was subsequently aired in North America on the Discovery Channel in 2000, with Branagh's voice replaced with that...
, which depicted it as an enormous 25 metre-long animal. However, this is not considered to be accurate for any species of Liopleurodon.
External links
- Liopleurodon information and photos, The Plesiosaur Directory
- Article on the giant pliosaur skull once assigned to Liopleurodon, Tetrapod Zoology