''Liopleurodon'' (; meaning 'smooth-sided teeth') is an
extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
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 nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...
pliosaurid
Pliosauridae is a family of plesiosaurian marine reptiles from the Latest Triassic to the early Late Cretaceous (Rhaetian to Turonian stages). The family is more inclusive than the archetypal short-necked large headed species that are placed in ...
pliosaur
Pliosauroidea is an extinct clade of plesiosaurs, known from the earliest Jurassic to early Late Cretaceous. They are best known for the subclade Thalassophonea, which contained crocodile-like short-necked forms with large heads and massive toot ...
s that lived from the
Callovian
In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 165.3 ± 1.1 Ma (million years ago) and 161.5 ± 1.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...
stage
Stage, stages, or staging may refer to:
Arts and media Acting
* Stage (theatre), a space for the performance of theatrical productions
* Theatre, a branch of the performing arts, often referred to as "the stage"
* ''The Stage'', a weekly Brit ...
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 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...
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 154.8 ±0.8 Ma and 149.2 ±0.7 Ma (million years ago). The Kimmeridgian follows the Oxfordian ...
stage of the
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
period
Period may refer to:
Common uses
* Period (punctuation)
* Era, a length or span of time
*Menstruation, commonly referred to as a "period"
Arts, entertainment, and media
* Period (music), a concept in musical composition
* Periodic sentence (o ...
(c. 166 to 155
mya). The
type species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
is ''L. ferox'', which is probably the only
valid species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
. Some studies also include the second species ''L. pachydeirus'', but this latter is considered as a probable
junior synonym
In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently.
...
of ''L. ferox'' due to its lack of viable
diagnosis
Diagnosis (: diagnoses) is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in a lot of different academic discipline, disciplines, with variations in the use of logic, analytics, and experience, to determine " ...
. Fossils attributed to ''Liopleurodon'', including some skeletons, are mainly known from Europe, with one occurrence reported in Mexico. As the
holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
specimen of ''L. ferox'' consists of a single tooth preserving questionable distinctive features, recent studies therefore recommend the necessary identification of a
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 associated. In other words, a type is an example that serves to anchor or centralizes ...
in order to preserve its validity. Other additional species were even proposed, but these are currently seen as coming from other pliosaurid genera.
''Liopleurodon'' is a representative of the
Thalassophonea
Pliosauridae is a family of plesiosaurian marine reptiles from the Latest Triassic to the early Late Cretaceous (Rhaetian to Turonian stages). The family is more inclusive than the archetypal short-necked large headed species that are placed in ...
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
, a derived group of pliosaurids characterized by a short
neck
The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...
and a large elongated
skull
The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate.
In the human, the skull comprises two prominent ...
. In 1999, the size of ''Liopleurodon'' was greatly exaggerated in the
BBC
The British Broadcasting Corporation (BBC) is a British public service broadcaster headquartered at Broadcasting House in London, England. Originally established in 1922 as the British Broadcasting Company, it evolved into its current sta ...
documentary 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. ...
'', depicted as reaching in length. However, the different attributed specimens show that the animal could reach a size ranging from long, with some researchers estimating a maximum length of approximately . Various studies suggest that ''Liopleurodon'' would have been an
ambush predator
Ambush predators or sit-and-wait predators are carnivorous animals that capture their prey via stealth, luring or by (typically instinctive) strategies utilizing an element of surprise. Unlike pursuit predators, who chase to capture prey u ...
, feeding on
fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
,
cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s and other
marine reptile
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including mari ...
s.
Research history

Even before ''Liopleurodon'' was named, material likely belonging to it was described in
scientific literature
Scientific literature encompasses a vast body of academic papers that spans various disciplines within the natural and social sciences. It primarily consists of academic papers that present original empirical research and theoretical ...
.
In 1838,
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 in Frankfurt am ...
applied the name ''
Ischyrodon meriani'' to a large tooth from possibly
Callovian
In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 165.3 ± 1.1 Ma (million years ago) and 161.5 ± 1.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...
-aged rocks in
Fricktal
The Fricktal ("Frick Valley") is a region on Northwestern Switzerland, comprising the Laufenburg and Rheinfelden districts of the Swiss canton of Aargau.
The region was known as ''Frickgau'' in the medieval period, ultimately from a Late Lati ...
, Switzerland.
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 a similar species, 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 ...
''.
In 1841, von Meyer named the species ''
Thaumatosaurus 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 Province of Hohenzollern, Hohenzollern, two other histo ...
, Germany, 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. He was also a pioneer of biogeographical theory.
Career
Wagner was born ...
published a description of a large plesiosaur tooth from
Bavaria
Bavaria, officially the Free State of Bavaria, is a States of Germany, state in the southeast of Germany. With an area of , it is the list of German states by area, largest German state by land area, comprising approximately 1/5 of the total l ...
, Germany, in 1852, assigning it to a new
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
that he named ''
Pliosaurus
''Pliosaurus'' (meaning 'more lizard') is an extinct genus of thalassophonean pliosaurid known from the Late Jurassic (Kimmeridgian and Tithonian stages) of Europe and South America. This genus has contained many species in the past but recent ...
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 by ...
'', ''Plesiosaurus giganteus'',
and this species was later viewed as a
synonym
A synonym is a word, morpheme, or phrase that means precisely 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 a ...
of either ''Pliosaurus brachydeirus'' or ''Pliosaurus 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 1860,
Hermann Trautschold
Gustav Heinrich Ludwig Hermann Trautschold (, tr. ; 17 September 1817 – October 22, 1902) was a German-Russian geologist and paleontologist and also pharmacist. From 1869 to 1888 he was a professor at the Petrovsky Agricultural and Forestry Ac ...
assigned the name ''Pliosaurus giganteus'' to a small tooth that was discovered 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 ...
of
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
, dating from the Oxfordian. This tooth is now thought to pertain to ''Liopleurodon'', but the name ''Pliosaurus giganteus'' having already been used twice by this point, Trautschold's name is also invalid.

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 Herpetology, herpetologist. He was a leading expert on Mesozoic fish and reptiles. in 1873. Sauvage named three species which he assigned to this genus, each based on a single tooth.
The
holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
tooth of ''Liopleurodon ferox'' was discovered in
Le Wast
Le Wast () is a commune in the Pas-de-Calais department in the Hauts-de-France region of France about east of Boulogne.
Population
Transport
The Chemin de fer de Boulogne à Bonningues (CF de BB) opened a station serving Le Wast and Alin ...
, near
Boulogne-sur-Mer
Boulogne-sur-Mer (; ; ; or ''Bononia''), often called just Boulogne (, ), is a coastal city in Hauts-de-France, Northern France. It is a Subprefectures in France, sub-prefecture of the Departments of France, department of Pas-de-Calais. Boul ...
,
and is since numbered as BHN 3R 197 and stored in the
Lille Natural History Museum
Lille (, ; ; ; ; ) is a city in the northern part of France, within French Flanders. Positioned along the Deûle river, near France's border with Belgium, it is the capital of the Hauts-de-France Regions of France, region, the Prefectures in F ...
.
More precisely, the tooth consists of a
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, parti ...
measuring long, coming from sedimentary layers dating from the Callovian.
Another tooth from
Charly
Charly may refer to:
People
* Charly (name)
Places
* Charly-sur-Marne, in the Aisne department
* Charly, Cher, in the Cher department
* Charly, Rhône, in the Rhône department
* Charly-Oradour, in the Moselle department
Other
* Operation ...
, since preserved at the
Paris School of Mines, embodies the holotype of ''L. grossouvrei''. This tooth is long, with the crown measuring . The third, discovered near
Caen
Caen (; ; ) is a Communes of France, commune inland from the northwestern coast of France. It is the Prefectures in France, prefecture of the Departments of France, department of Calvados (department), Calvados. The city proper has 105,512 inha ...
, France, was originally attributed to ''
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 description.
The genus name ''Liopleurodon'' derives from
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
', "smooth"; ', "side" or "rib"; and ', "tooth", all meaning "smooth-sided tooth", in reference to the very contrasting dentition of the animal. The
specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
derives from
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
''ferox'', meaning "fierce", in reference to the large size of the teeth.
However, in 1880, Sauvage synonymized ''Liopleurodon'' with ''
Polyptychodon
''Polyptychodon'' (meaning 'many-folded 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 discover ...
'', 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 a British naturalist, geologist and writer of numerous books on natural history. He was known for his contributions to zoology, paleontology, and biogeography. He worked extensively in cata ...
, 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 from the Oxford Clay Formation, near
Peterborough
Peterborough ( ) is a City status in the United Kingdom, cathedral city in the City of Peterborough district in the Ceremonial counties of England, ceremonial county of Cambridgeshire, England. The city is north of London, on the River Nene. A ...
, 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 fa ...
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 mile ...
. Other than its large size,
Seeley provided no distinguishing characteristics. The specific name ''pachydeirus'' means "stout neck", due to its vertebral morphology.
Lydekker stated in 1888 that the neck described by Seeley probably belonged to ''Pliosaurus ferox''.
Walerian Kiprijanoff named ''Thaumatosaurus mosquensis'' in 1883 based on remains including teeth, vertebrae, and limb bones from Oxfordian-aged rocks of the Moscow Basin.
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 town and civil parishes in England, civil parish in the North Northamptonshire district, in the ceremonial county of Northamptonshire, England, around east of Northampton. The parish is on the border with Bedfordshire, north of B ...
, 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 ( 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 the ge ...
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
marine reptile
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including mari ...
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 (Lo ...
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
Fletton is an area of the city of Peterborough, in the Peterborough district, in the ceremonial county of Cambridgeshire, England, south of the River Nene.
Notable for its large brickworks, the area has given its name to " Fletton bricks".
Adm ...
, England, housed in Institut für Geowissenschaften,
University of Tübingen
The University of Tübingen, officially the Eberhard Karl University of Tübingen (; ), is a public research university located in the city of Tübingen, Baden-Württemberg, Germany.
The University of Tübingen is one of eleven German Excellenc ...
. 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 (), abbreviated SMNS, is one of the two state of Baden-Württemberg's natural history museums. Together with the State Museum of Natural History Karlsruhe (Staatliches Museum für Naturkunde Karls ...
as specimens of ''Pliosaurus 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 ''Pliosaurus grandis'' that was housed in Stuttgart was destroyed during
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
.
In 1934,
Friedrich von Huene
Baron Friedrich Richard von Hoyningen-Huene (22 March 1875 – 4 April 1969) was a German nobleman paleontologist who described a large number of dinosaurs, more than anyone else in 20th-century Europe. He studied a range of Permo-Carbonife ...
described a partial skeleton from
Swabia
Swabia ; , 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 Swabia, one of ...
, Germany. As Linder, he also used the name ''Pliosaurus ferox'' instead of ''Liopleurodon ferox''.
In 1938, Alexandre Bigot used ''Pliosaurus ferox'' as well, assigning some teeth known from
Calvados
Calvados (, , ) is a brandy from Normandy in France, made from apples and/or pears.
History In France
Apple orchards and brewers are mentioned as far back as the 8th century by Charlemagne. The first known record of Norman distillation was ma ...
, in the north of France.
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 (: 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 either side ...
(although this was later discovered to be an
ilium).
In 1992, David Martill identified a fragmentary specimen belonging to a young individual, PETCM R.296, as cf. ''Liopleurodon'' sp.; the specimen was found to have at least 7
gastroliths
A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In oth ...
in its stomach and soft tissues, although the specific features of the latter cannot be observed due to poor preservation.
[ The following year, Nathalie Bardet and her colleagues attributed two teeth to ''L. ferox'', having been discovered in the French town of ]Villers-sur-Mer
Villers-sur-Mer () is a commune in the Calvados department in Normandy, northwestern France, with a population of 2,644 as of 2017.
Geography
The commune is located on the French coast of the English Channel, on the Côte Fleurie, between ...
, Normandy
Normandy (; or ) is a geographical and cultural region in northwestern Europe, roughly coextensive with the historical Duchy of Normandy.
Normandy comprises Normandy (administrative region), mainland Normandy (a part of France) and insular N ...
.
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
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the s ...
. 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.
As mentioned previously, ''Liopleurodon'' fossils have been found mainly in England and France. Contemporary fossil specimens referrable to ''Liopleurodon'', dating from the Callovian 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 154.8 ±0.8 Ma and 149.2 ±0.7 Ma (million years ago). The Kimmeridgian follows the Oxfordian ...
, are also known from Germany. 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 Municipalities of Oaxaca, 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 ...
in Oaxaca
Oaxaca, officially the Free and Sovereign State of Oaxaca, is one of the 32 states that compose the political divisions of Mexico, Federative Entities of the Mexico, United Mexican States. It is divided into municipalities of Oaxaca, 570 munici ...
, Mexico. These fossils were extracted from Kimmeridgian deposits in the Sabinal Formation
The Sabinal Formation is a Late Jurassic and Early Cretaceous-aged geological formation in Oaxaca, Mexico. It preserves a highly diverse marine fauna.
It was initially thought to only encompass the Late Jurassic (Kimmeridgian & Tithonian), but m ...
, 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. ''L. 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 associated. In other words, a type is an example that serves to anchor or centralizes ...
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. In 2024, Peggy Vincent and coauthors described a partial postcranial skeleton that was discovered in 1979 in a since-abandoned quarry in Saint-Laon, France. Like the holotype tooth, this skeleton, informally termed as the Thouarsais specimen, also comes from sedimentary layers dating from the Callovian. Measuring around long as preserved, the fossil is among the most complete ''Liopleurodon'' postcranial skeletons known and the most complete French specimen.
Description
Plesiosaurs typically can be described as being of the small-headed, long-necked "plesiosauromorph" morphotype or the large-headed, short-necked "pliosauromorph" morphotype, ''Liopleurodon'' belonging to the latter category. Like all plesiosaurs, it had a short tail
The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to los ...
, a massive trunk
Trunk may refer to:
Biology
* Trunk (anatomy), synonym for torso
* Trunk (botany), a tree's central superstructure, and the stem of woody plants
* Trunk of corpus callosum, in neuroanatomy
* Elephant trunk, the proboscis of an elephant
Comput ...
and two pairs of large flippers.
Size
In his original 1873 description, Sauvage noted that the holotype tooth of ''L. ferox'' came from an animal which, according to him, had reached "completely gigantic proportions". ''Liopleurodon'' first came to the public attention in 1999 when it was featured in an episode of the BBC
The British Broadcasting Corporation (BBC) is a British public service broadcaster headquartered at Broadcasting House in London, England. Originally established in 1922 as the British Broadcasting Company, it evolved into its current sta ...
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. ...
'', which depicted it as an enormous apex predator
An apex predator, also known as a top predator or superpredator, 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 hig ...
reaching long for . This representation is based on a vertebra discovered near Peterborough, with which Martill, then consultant to the series, extrapolated it to a size today recognized as very exaggerated but at the time seen as reliable. However, later descriptions deny this, including one led by Martill himself, the remains of very large pliosaurs being often fragmentary and probably not being as imposing as the largest cetacea
Cetacea (; , ) is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively c ...
ns. In addition, doubts were expressed by some authors as to the real nature of the Peterborough vertebra, a 2019 study finally re-identified it as actually coming from a sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
.
The palaeontologist L. B. Tarlo suggested that the pliosaurs’ total body length can be estimated from the length of their skull which he claimed was typically one-seventh of the former measurement. Additional ''Kronosaurus
''Kronosaurus'' ( ) is an extinct genus of large short-necked pliosaur that lived during the Aptian to Albian Stage (stratigraphy), stages of the Early Cretaceous in what is now Australia. The first known specimen was received in 1899 and consis ...
'' specimens and a skeleton of ''L. ferox'', GPIT 1754/2, show that the pliosaurs’ skulls were actually about one-fifth of their total body length. One large skull specimen of ''L. ferox'', CAMSMJ.27424, has an estimated total body length of .[ McHenry estimated that smaller individuals measuring about long would have weighed around based on the specimen NHM R2680.] In 2024, Ruizhe Jackevan Zhao estimates that the largest known specimen of ''Liopleurodon'', NHMUK PV R3536, would have reached a length of approximately with a body mass of .
Some researchers propose larger estimates of over . Tarlo applied the aforementioned one-seventh ratio of skull length to body length, estimating that the largest known specimen of ''L. ferox'' was a little over , though a more typical size range would be from . In the 2023 book ''Ocean Life in the Time of Dinosaurs'', Bardet and colleagues also claimed that some individuals could reach lengths of over .
Classification
''Liopleurodon'' belongs to clade Thalassophonea
Pliosauridae is a family of plesiosaurian marine reptiles from the Latest Triassic to the early Late Cretaceous (Rhaetian to Turonian stages). The family is more inclusive than the archetypal short-necked large headed species that are placed in ...
, 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). The family is more inclusive than the archetypal short-necked large headed species that are placed ...
, a family of plesiosaurs
The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...
, 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.
The following cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...
follows Ketchum and Benson, 2022:
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.
A fragmentary specimen possibly belonging to a young individual, PETCM R.296, contained numerous hooklets of teuthoid cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s, fish bones and a single reptilian tooth in its stomach. Although its exact dietary preference cannot be determined, Martill proposed three suggestions. One possibility is that ''Liopleurodon'' could have fed on food supplies that are abundant (i.e. squids), but considering that plesiosaurs and ichthyosaurs were also abundant and that the plesiosaurs' swimming speed is likely very slow compared to squids, this interpretation may be unlikely unless ''Liopleurodon'' was an ambush predator. Another possibility is that ''Liopleurodon'' may have been an opportunistic feeder, with cephalopod hooklets being representative of the acid resistant residue of its varied diet—skeletal components of various vertebrates that lost to the acid environment of the gut; however, since the thin sections through the gut don't reveal the presence of otolith
An otolith (, ' ear + , ', a stone), also called otoconium, statolith, or statoconium, is a calcium carbonate structure in the saccule or utricle (ear), utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule ...
s (calcium carbonate structure of vertebrates located in the vestibular labyrinth) which are known to occur in the gut of cetaceans, fish may not have been an important part of its diet. The other possibility is that the pliosaur fed on large cephalopod-feeders, with the hooklets representing the residues of the stomach contents of the pliosaur's prey, but there is no firm evidence to this claim. It is also notable that this specimen preserved at least 7 gastroliths, which probably weren't used for grinding based on the well-preserved conditions of the hooklets. It is possible either that the pliosaur accidentally swallowed the stones and they remained in its gut, or that the stones represent the "acid resistant residue from carbonate cemented sandstone."
See also
* 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 ...
* Timeline of plesiosaur research
This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, Taxonomy (biology), taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles ...
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
Pliosauridae
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
Apex predators