Baryonyx
Encyclopedia
Baryonyx is a genus
of carnivorous
saurischia
n dinosaur
first discovered in clay
pits just south of Dorking
, England
, and later reported from fossils found in northern Spain
and Portugal
. It is known to contain only one species
, Baryonyx walkeri. Its fossils have been recovered from formations dating from the Hauterivian
to early Barremian
stages of the early Cretaceous
Period, around 130-125 million years ago.
Baryonyx is one of the few known piscivorous
(fish
-eating) dinosaurs, with specialized adaptations like a long low snout with narrow jaws filled with finely serrated teeth and gaff-hook-like claws to help it hunt its main prey.
Baryonyx was about 8.5 m (28 ft) long and weighed in the region of 1,700 kg. However, analysis of the bones suggests that the most complete specimen was not yet fully grown, so Baryonyx may have grown even larger.
Baryonyx had a large claw on the thumb of each hand
, which measured about 25 centimetres (9.8 in) in a straight line from tip to base. Its long neck was not as strongly S-curved as in many other theropods. The skull
was set at an acute angle
, not the 90° angle common in similar dinosaurs. The long jaws were distinctly crocodilian
and had 96 teeth, about twice as many as Tyrannosaurus
. Sixty-four of the teeth were placed in the lower jaw (mandible), and 32 large ones in the upper (maxilla). The teeth had slight keels on their leading and posterior sides, with fine serrations (7 per 1 millimetre (0.0393700787401575 in)). There was a knob-like protuberance on the nasal bone
s. The upper jaw had a sharp angle near the snout, a feature seen in crocodiles that helps to prevent prey from escaping. A similar feature is also seen in shrike
s.
During the early Cretaceous
, Wealden Lake
covered the majority of what is now northern Europe
. Alluvial plain
s and deltas
spread from the uplands surrounding the area where London
now stands and eventually ran into this great lake.
Baryonyx was discovered in these former deltas. In January 1983, an amateur fossil hunter named William Walker came across an enormous claw sticking out of the side of a clay pit - Smokejacks Pit at Wallis Wood, Ockley
near Dorking
in Surrey
(United Kingdom). He received some help in retrieving the claw and several other fossil bones from the site. Subsequently he contacted the Natural History Museum
in London about his find.
The skeleton was fortunately found to be in a relatively intact state and was excavated by a team led by Alan J. Charig
and Angela C. Milner of the Natural History Museum. They published their description of the type species
, B. walkeri, in 1986, and named it after Walker. The skeleton can now be seen mounted at the Natural History Museum in London
. About 70% of the skeleton was recovered including the skull, enabling paleontologists to make numerous deductions about Baryonyx from just this first specimen.
Some years after the initial discovery in England, a partial skull of Baryonyx was found in the Sala de los Infantes deposit of Burgos Province
, Spain
. Some of the famous and abundant dinosaur fossil tracks of La Rioja
, near Burgos, have been identified as tracks of Baryonyx or another theropod genus very similar to it. Two more claws have been found in the Niger Republic in West Africa, and another in 1996 on the Isle of Wight
. In December 1997, a store of old fossils in the Isle of Wight Museum yielded a forearm of a Baryonyx. These remains had apparently been unearthed decades earlier on the southwest coast of the island, and had sat unclassified in a box in Carisbrooke Castle
since that time.
Jaw fragments and teeth from Portugal, originally thought to belong to Suchosaurus girardi
, were later identified as Baryonyx walkeri by paleontologist Eric Buffetaut.
, was described in 1998, and placed together with Baryonyx in the subfamily
Baryonychinae. The Baryonychinae is a subdivision of the family Spinosauridae
, which contains other giant Cretaceous
forms from Africa
and South America
, including the genera Spinosaurus
and Irritator
.
In 2004, paleontologists Hutt and suggested that Suchomimus tenerensis should be redefined as Baryonyx tenerensis due to new discoveries that showed the vertebrae of Baryonyx were more similar to those of Suchomimus than previously thought.
Additionally, the similarity between Baryonyx and Suchosaurus
was noted by Buffetaut in 2007. Remains long attributed to Suchosaurus are now assigned to Baryonyx, and it is difficult to distinguish between remains of these two dinosaurs. Some minor differences do exist, such as ridges on the teeth of Suchosaurus. However, a similar range of variation exists among Baryonyx specimens, and even among various teeth assigned to the related Spinosaurus
. Buffetaut suggested that this could mean that either various Baryonyx specimens should be broken up into separate taxa, or that Suchosaurus could be a senior synonym of Baryonyx. Buffetaut noted that if this is the case, the name Baryonyx would be replaced with Suchosaurus, which could be problematic given that the holotype
specimen of Suchosaurus is only a single, worn tooth.
The crocodile-like jaws and large number of finely serrated teeth suggested to scientists that Baryonyx was a fish-eater. As confirmation, a number of scales and bones from the fish Lepidotes
were also discovered in the body cavity of the English specimen.
It is speculated that Baryonyx would sit on a riverbank, resting on its front legs, and then sweep fish from the river with its powerful striking claw. This is similar to the modern grizzly bear
.
Until the discovery of the closely related Suchomimus
, Baryonyx was the only known piscivorous
(fish-eating) dinosaur. On the other hand, bones of the ornithopod
dinosaur Iguanodon
were also found in association with the Baryonyx skeleton.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of carnivorous
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...
saurischia
Saurischia
Saurischia meaning 'lizard' and ischion meaning 'hip joint') is one of the two orders, or basic divisions, of dinosaurs. In 1888, Harry Seeley classified dinosaurs into two orders, based on their hip structure...
n dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
first discovered in clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
pits just south of Dorking
Dorking
Dorking is a historic market town at the foot of the North Downs approximately south of London, in Surrey, England.- History and development :...
, 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 later reported from fossils found in northern Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
. It is known to contain only one species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, Baryonyx walkeri. Its fossils have been recovered from formations dating from the Hauterivian
Hauterivian
The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous epoch or a stage in the Lower Cretaceous series. It spans the time between 136.4 ± 2 Ma and 130 ± 1.5 Ma...
to early Barremian
Barremian
The Barremian is an age in the geologic timescale between 130.0 ± 1.5 Ma and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch...
stages of the early Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period, around 130-125 million years ago.
Baryonyx is one of the few known piscivorous
Piscivore
A piscivore is a carnivorous animal which eats primarily fish. Piscivory was the diet of early tetrapods , insectivory came next, then in time reptiles added herbivory....
(fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
-eating) dinosaurs, with specialized adaptations like a long low snout with narrow jaws filled with finely serrated teeth and gaff-hook-like claws to help it hunt its main prey.
Description
Baryonyx had a large claw on the thumb of each hand
Hand
A hand is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs...
, which measured about 25 centimetres (9.8 in) in a straight line from tip to base. Its long neck was not as strongly S-curved as in many other theropods. The skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
was set at an acute angle
Angle
In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
, not the 90° angle common in similar dinosaurs. The long jaws were distinctly crocodilian
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
and had 96 teeth, about twice as many as Tyrannosaurus
Tyrannosaurus
Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...
. Sixty-four of the teeth were placed in the lower jaw (mandible), and 32 large ones in the upper (maxilla). The teeth had slight keels on their leading and posterior sides, with fine serrations (7 per 1 millimetre (0.0393700787401575 in)). There was a knob-like protuberance on the nasal bone
Nasal bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, "the bridge" of the nose.Each has two surfaces and four borders....
s. The upper jaw had a sharp angle near the snout, a feature seen in crocodiles that helps to prevent prey from escaping. A similar feature is also seen in shrike
Shrike
Shrikes are passerine birds of the family Laniidae. The family is composed of thirty-one species in three genera. The family name, and that of the largest genus, Lanius, is derived from the Latin word for "butcher", and some shrikes were also known as "butcher birds" because of their feeding habits...
s.
Discovery and naming
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, Wealden Lake
Wealden Lake
Wealden Lake was a freshwater lake which existed over the lands now considered to be northern France and southern England during the early Cretaceous...
covered the majority of what is now northern 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...
. Alluvial plain
Alluvial plain
An alluvial plain is a relatively flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms...
s and deltas
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
spread from the uplands surrounding the area where London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
now stands and eventually ran into this great lake.
Baryonyx was discovered in these former deltas. In January 1983, an amateur fossil hunter named William Walker came across an enormous claw sticking out of the side of a clay pit - Smokejacks Pit at Wallis Wood, Ockley
Ockley
Ockley is a historic village in Surrey, built on Stane Street, a Roman Road stretching from Chichester to London. Situated between Dorking and Horsham, close to the Sussex/Surrey border, Ockley nestles in the shadows of Leith Hill, the highest point in South east England. Neighbouring villages...
near Dorking
Dorking
Dorking is a historic market town at the foot of the North Downs approximately south of London, in Surrey, England.- History and development :...
in Surrey
Surrey
Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...
(United Kingdom). He received some help in retrieving the claw and several other fossil bones from the site. Subsequently he contacted the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
in London about his find.
The skeleton was fortunately found to be in a relatively intact state and was excavated by a team led by Alan J. Charig
Alan J. Charig
Alan Jack Charig was an English palaeontologist and writer who popularised his subject on television and in books at the start of the wave of interest in dinosaurs in the 1970s....
and Angela C. Milner of the Natural History Museum. They published their description of the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, B. walkeri, in 1986, and named it after Walker. The skeleton can now be seen mounted at the Natural History Museum in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
. About 70% of the skeleton was recovered including the skull, enabling paleontologists to make numerous deductions about Baryonyx from just this first specimen.
Some years after the initial discovery in England, a partial skull of Baryonyx was found in the Sala de los Infantes deposit of Burgos Province
Burgos (province)
The province of Burgos is a province of northern Spain, in the northeastern part of the autonomous community of Castile and León. It is bordered by the provinces of Palencia, Cantabria, Vizcaya, Álava, La Rioja, Soria, Segovia, and Valladolid. Its capital is the city of Burgos...
, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
. Some of the famous and abundant dinosaur fossil tracks of La Rioja
La Rioja (Spain)
La Rioja is an autonomous community and a province of northern Spain. Its capital is Logroño. Other cities and towns in the province include Calahorra, Arnedo, Alfaro, Haro, Santo Domingo de la Calzada, and Nájera.-History:...
, near Burgos, have been identified as tracks of Baryonyx or another theropod genus very similar to it. Two more claws have been found in the Niger Republic in West Africa, and another in 1996 on the Isle of Wight
Isle of Wight
The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
. In December 1997, a store of old fossils in the Isle of Wight Museum yielded a forearm of a Baryonyx. These remains had apparently been unearthed decades earlier on the southwest coast of the island, and had sat unclassified in a box in Carisbrooke Castle
Carisbrooke Castle
Carisbrooke Castle is a historic motte-and-bailey castle located in the village of Carisbrooke, near Newport, Isle of Wight, England. Charles I was imprisoned at the castle in the months prior to his trial.-Early history:...
since that time.
Jaw fragments and teeth from Portugal, originally thought to belong to Suchosaurus girardi
Suchosaurus
Suchosaurus is as a spinosaurid theropod dinosaur from Cretaceous England, originally believed to be a genus of crocodile. The type material consists of teeth. Two species, S. cultridens and S. girardi have been named, though the S. girardi material was reclassified by Buffetaut as Baryonyx...
, were later identified as Baryonyx walkeri by paleontologist Eric Buffetaut.
Classification
Another crocodile-like fish-eater, SuchomimusSuchomimus
Suchomimus is a genus of large spinosaurid dinosaur with a crocodile-like mouth that lived sometime between 121-112 million years ago, during the late Aptian stage of the Cretaceous period in Africa.-Description:...
, was described in 1998, and placed together with Baryonyx in the subfamily
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Baryonychinae. The Baryonychinae is a subdivision of the family Spinosauridae
Spinosauridae
Spinosauridae is a family of specialised theropod dinosaurs. Members of this family were large, bipedal predators with elongated, crocodile-like skulls, sporting conical teeth with no or only very tiny serrations. The front dentary teeth fanned out, giving the animal a characteristic look...
, which contains other giant Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
forms from Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, including the genera Spinosaurus
Spinosaurus
Spinosaurus is a genus of theropod dinosaur which lived in what is now North Africa, from the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago. This genus was first known from Egyptian remains discovered in 1912 and described by German...
and Irritator
Irritator
Irritator is a genus of spinosaurid dinosaur that lived in the early Cretaceous Period , around 110 million years ago. Current estimations indicate a length of 8 meters . It was found in Brazil...
.
In 2004, paleontologists Hutt and suggested that Suchomimus tenerensis should be redefined as Baryonyx tenerensis due to new discoveries that showed the vertebrae of Baryonyx were more similar to those of Suchomimus than previously thought.
Additionally, the similarity between Baryonyx and Suchosaurus
Suchosaurus
Suchosaurus is as a spinosaurid theropod dinosaur from Cretaceous England, originally believed to be a genus of crocodile. The type material consists of teeth. Two species, S. cultridens and S. girardi have been named, though the S. girardi material was reclassified by Buffetaut as Baryonyx...
was noted by Buffetaut in 2007. Remains long attributed to Suchosaurus are now assigned to Baryonyx, and it is difficult to distinguish between remains of these two dinosaurs. Some minor differences do exist, such as ridges on the teeth of Suchosaurus. However, a similar range of variation exists among Baryonyx specimens, and even among various teeth assigned to the related Spinosaurus
Spinosaurus
Spinosaurus is a genus of theropod dinosaur which lived in what is now North Africa, from the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago. This genus was first known from Egyptian remains discovered in 1912 and described by German...
. Buffetaut suggested that this could mean that either various Baryonyx specimens should be broken up into separate taxa, or that Suchosaurus could be a senior synonym of Baryonyx. Buffetaut noted that if this is the case, the name Baryonyx would be replaced with Suchosaurus, which could be problematic given that the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen of Suchosaurus is only a single, worn tooth.
Paleoecology
Lepidotes
Lepidotes is an extinct genus of neopterygian ray-finned fish from the Jurassic and Cretaceous periods. Fossils have been found worldwide....
were also discovered in the body cavity of the English specimen.
It is speculated that Baryonyx would sit on a riverbank, resting on its front legs, and then sweep fish from the river with its powerful striking claw. This is similar to the modern grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...
.
Until the discovery of the closely related Suchomimus
Suchomimus
Suchomimus is a genus of large spinosaurid dinosaur with a crocodile-like mouth that lived sometime between 121-112 million years ago, during the late Aptian stage of the Cretaceous period in Africa.-Description:...
, Baryonyx was the only known piscivorous
Piscivore
A piscivore is a carnivorous animal which eats primarily fish. Piscivory was the diet of early tetrapods , insectivory came next, then in time reptiles added herbivory....
(fish-eating) dinosaur. On the other hand, bones of the ornithopod
Ornithopod
Ornithopods or members of the clade Ornithopoda are a group of ornithischian dinosaurs that started out as small, bipedal running grazers, and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world, and dominated the North American...
dinosaur Iguanodon
Iguanodon
Iguanodon is a genus of ornithopod dinosaur that lived roughly halfway between the first of the swift bipedal hypsilophodontids and the ornithopods' culmination in the duck-billed dinosaurs...
were also found in association with the Baryonyx skeleton.