An Ultimate Guide to Baryonyx: The Heavy Claw

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Name MeaningHeavy ClawHeight2.5 meters (8.2 feet)
PronunciationBAR-ee-ON-iksLength8–10 meters (26–33 feet)
EraMesozoicEarly CretaceousWeight1–2 tons (2,000-4000 pounds)
ClassificationDinosauria,‭ Saurischia & TheropodaLocationEngland, Spain (Europe)

Baryonyx Pictures

Baryonyx ,dinosaur on white background Clipping path
Baryonyx | Kitti Kahotong via iStock

The Baryonyx

Gage Beasley Prehistoric's Baryonyx Concept
Gage Beasley Prehistoric’s Baryonyx Concept

Baryonyx is a genus of carnivorous (probably piscivorous) dinosaur that lived in England during the Early Cretaceous period (between 130 to 125 million years ago).

It was first discovered in the Smokejack Clay Pit, located in Surrey, England, in 1983 by an Amateur fossil collector.

Since then, other fossils of this dinosaur have turned up in other locations across Europe.

The dinosaur’s name translates as “heavy claw,” a reference to the large claws on its first finger that measured up to 30 centimeters.

The first described fossil of this dinosaur is one of the most complete theropod dinosaur fossils ever found in the United Kingdom.

As such, a lot is known about the anatomy of the Baryonyx and how it lived.

In this post, we’ll discuss the unique anatomy of this dinosaur (which is unlike any other dinosaur discovered so far) and other interesting facts about it. 

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Physical Characteristics 

A hand drawing of Baryonyx on white background
A hand drawing of Baryonyx on white background | Mateusz Atroszko via iStock

Baryonyx was a genus of lizard-hipped dinosaur (order Saurischia) that lived during the Early Cretaceous period.

It was a relatively large dinosaur with a length estimate of about eight to 10 meters (26 to 33 feet).

It stood at about 2.5 meters (8.2 feet) tall at the hip.

But since this dinosaur was bipedal, it could have been as much as 3 meters (10 feet) tall when standing on its hind feet. 

Baryonyx weighed between 1.2 and 2 tons.

It had a long and slender body which was slightly slimmer and longer compared to other theropod dinosaurs.

Its body was supported on powerful hind limbs, and its slightly shorter forelimbs had prominent sharp claws.

The large claws of this dinosaur which were up to one foot (30 centimeters) long, are one of its most prominent features.

Gage Beasley Prehistoric's Baryonyx Size Comparison
Gage Beasley Prehistoric’s Baryonyx Size Comparison

The big claw was the first Baryonyx bone to be recovered, and the dinosaur is named after it. 

Another prominent feature of the Baryonyx is its long and narrow snout.

The full length of the Baryonyx’s skull is about 91 to 95 centimeters (36–37 inches).

The general shape of the snout and the dinosaur’s dentition is similar to that of modern-day crocodiles.

However, Baryonyx had a low bony crest on top of its snout.

The dinosaur’s dentition was also similar to that of the crocodile. It had powerful jaws with up to a hundred small serrated fish.

The teeth were curved backward and were suited for gripping and catching slippery prey, prompting speculations that this dinosaur was a fish eater. 

Baryonyx walkeri, a prehistoric era dinosaur from the Early Cretaceous period
Baryonyx walkeri, a prehistoric-era dinosaur from the Early Cretaceous period | Sergey Krasovskiy via GettyImages

Baryonyx had an S-shaped neck with tall, triangular-shaped neural spines running along the back.

These spines increased in height from the front to the back, forming a sail-like structure on the dinosaur’s back.

This sail was probably used for thermoregulation or display. A sail-like structure like this is seen in the Spinosaurus, Baryonyx’s closest relative.

However, it is significantly pronounced in the Spinosaurus.

Both dinosaurs share other similarities, such as their elongated snouts and a possible adaptation to an aquatic or semi-aquatic lifestyle. 

Habitat and Distribution

Baryonyx is known from fossils recovered from various locations across Europe (notably England and Spain).

The dinosaur was alive during the Early Cretaceous period.

The distribution of this dinosaur’s fossil indicates that its range covered parts of Europe, including the modern-day United Kingdom and Spain. 

Baryonyx was primarily terrestrial but may have been adapted to a semi-aquatic lifestyle, which means it was capable of swimming.

The position of the dinosaur’s nostril on the sides of its snout and the general form of its skeleton means it could not have spent a significant amount of time in the water and was not fully submerged. 

However, fossils of this dinosaur are often found associated with coastal or river environments.

This suggests that the Baryonyx lived near water bodies during its life.

Illustration of Baryonyx standing upright
Illustration of Baryonyx standing upright | Sebastian Kaulitzki via GettyImages

It probably lived more on land but would visit coastal areas, lakes, or shallow rivers to catch prey. 

During the Early Cretaceous, the climate and ecosystem of Europe were significantly different from present-day conditions because the continent was closer to the equator than its current position.

The climate was temperate, and the global temperature was significantly higher. 

The landscape was also significantly different.

The Weald area of Surrey, where the first fossil of this dinosaur was discovered, was partly covered by a large body of fresh-to-brackish water known as the Wealden Lake.

The northern area was also drained by two large rivers flowing into the lake.

Baryonyx lived in an area with a sub-tropical climate similar to that of present-day Mediterranean regions. 

Behavior and Diet 

Baryonyx ,dinosaur on white background Clipping path
Baryonyx | Kitti Kahotong via iStock

Scientists initially thought Baryonyx was a quadrupedal dinosaur.

This would have made the dinosaur unique since other theropods are bipedal.

However, recent studies show that it was indeed bipedal like its closest relatives.

The dinosaur had powerful hind limbs which were capable of quick and agile movement.

However, it may have also been able to work on all fours since the forelimbs were not strong enough to help with stability and maneuvering.

Baryonyx was a carnivore with a special adaptation to a fish-based diet.

A Baryonyx walkeri dinosaur catches a fish as its next meal
A Baryonyx walkeri dinosaur catches a fish as its next meal | Heraldo Mussolini via GettyImages

However, it may have been capable of hunting and eating other small animals as well.

Scientists found pieces of partially digested fossilized meal in the stomach of one Baryonyx fossil.

The meal contained fish scales, bones, and bones from a young Iguanodon.

This suggests that the dinosaur was piscivorous but was probably an opportunistic carnivore as well.  

Another fish-eating adaptation for this dinosaur was the nature of its snout and dentition.

It had a long, narrow snout filled with sharp, conical teeth.

Baryonyx swimming amongst some Lepidotes fish
Baryonyx swimming amongst some Lepidotes fish | Vitor Silva via GettyImages

This dentition is the type seen in other animals well adapted to catching slippery prey like fish.

Since the teeth were not serrated, Baryonyx probably swallowed its prey whole, but it may have also used its large claws to dismember prey before eating them.

Their jaw articulation is similar to those of living pelicans which supports the theory that they were capable of swallowing large prey whole.

Baryonyx was a solitary dinosaur, as scientists have not found any evidence of social structures or group behavior in fossils recovered so far.

This means individuals would have lived and hunted alone, possibly occupying different territories across their home range. 

Life Cycle 

Baryonyx stock illustration
Baryonyx | Sebastian Kaulitzki via GettyImages

Like other dinosaurs, Baryonyx likely reproduced sexually.

They were oviparous, meaning females laid clutches of eggs from which juveniles hatched.

This behavior is seen in many reptiles and birds today. 

No fossil of juvenile Baryonyx has been found so far, although some scientists believe the type fossil of this genus was not a fully-mature individual.

Members of this genus probably experienced rapid growth, reaching maturity relatively quickly.

The exact duration of their growth phase is uncertain, but it would have lasted several years.

Baryonyx walkeri dinosaur painting
Baryonyx walkeri dinosaur painting | Aram Papazyan via GettyImages

It also isn’t clear if this dinosaur exhibited parental care for their young or not.

Juvenile spinosaurid fossils are generally rare.

However, scientists found modified toenail bones (ungual phalanx bone) belonging to a young Spinosaurus.

This was an adaptation used to hunt underwater, and it has been taken as evidence that young spinosaurids most likely developed their semiaquatic adaptations at birth or very early in their life and maintained this adaptation throughout their life. 

Evolution and History 

Baryonyx walkeri fishing while a Pelecanimimus observes from the other side.
Baryonyx walkeri fishing while a Pelecanimimus observes from the other side | Roman Garcia Mora via GettyImages

Baryonyx belongs to the family Spinosauridae, a group of theropod dinosaurs that also includes other notable species such as Spinosaurus and Suchomimus.

These dinosaurs shared similar characteristics and adaptations, particularly in their elongated snouts, dorsal sails, and potential affinity for aquatic habitats.

The evolutionary history of the spinosaurid group can be traced back to their earlier ancestors, which were most likely small bipedal theropods.

Over time, the spinosaurids became adapted to different environments and niches and underwent significant morphological changes.

Scientists believe the spinosaurid dinosaurs first evolved during the Early Cretaceous in Laurasia.

This was a supercontinent made up of landmasses of present-day North America, Europe, and Asia. 

Baryonyx dinosaur, side view on white background
Baryonyx side view on white background | Robert Fabiani via GettyImages

The Iberian Peninsula (where a few Baryonyx fossils have been discovered) was likely the center of spinosaurid diversity during the Early Cretaceous period.

From here, some members of the group migrated to other parts of the earth, including Africa and Asia, where they diversified even more. 

For the group that remained in Europe, members of the Baryonychines subfamily (including Baryonyx) were dominant.

The African continent, on the other hand, saw the proliferation of a second group known as the spinosaurines.

The Spinosaurus is the most notable member of this group. 

When fossils of the Baryonyx were first discovered in 1983, it was the first Early Cretaceous theropod found anywhere in the world.

This means it was the oldest known theropod dinosaur at the time, filling a crucial gap in the reconstruction of the evolutionary timeline of the theropod dinosaurs. 

Baryonyx walkeri at the National History Museum in London
Baryonyx walkeri at the National History Museum in London | Nic McPhee via Flickr

As they evolved, Baryonyx and other spinosaurids developed various unique adaptations that set them apart from other theropod dinosaurs.

One of the most notable adaptations is their elongated snouts which were adapted for their piscivorous diet.

Their snout also had numerous sharp teeth (more than any other theropod dinosaur).

The nature of their dentition allows them to efficiently grasp the type of prey they were adapted to hunting.

Spinosaurids also had sail-like structures on their back and spine. This may have served thermoregulatory or display purposes.

Interaction With Other Species

A Baryonyx dinosaur catches a fish out of water in the Cretaceous Period
A Baryonyx dinosaur catches a fish out of water in the Cretaceous Period | Yuriy Priymak via GettyImages

The part of Europe where the Baryonyx was found was home to several other dinosaur groups, including the ornithopods, sauropods, and theropods.

Some of the other dinosaurs found in this area include Riparovenator, Ceratosuchops, Iguanodon, Hypsilophodon, Eucamerotus, and Chondrosteosaurus

In addition to the dinosaurs, several other vertebrates and invertebrate groups have been identified from the region.

They include lizards, pterosaurs, and crocodilians. The area was also home to various invertebrates on land and in the aquatic habitat.

Baryonyx was adapted to a fish-based diet.

It occupied a niche as a top predator in aquatic environments, where it targeted various fish species, including freshwater and marine fishes.

Various fish groups have been identified in the Smokejacks Pit, including some primitive sharks like Hybodus and bony fishes such as Scheenstia.

Fossil reconstruction of Baryonx
Fossil reconstruction of Baryonx | ケラトプスユウタ via Wikimedia CC BY-SA 4.0

These and other fish species may have served as food for the Baryonyx.

Since it was a top predator in its environment, very few dinosaurs would have posed a threat to the Baryonyx.

However, larger theropods and other large carnivorous dinosaurs may have posed a threat to younger or weak individuals.

Baryonyx had robust forelimbs with sharp claws, which may have served as weapons to defend the dinosaur against potential threats. 

Baryonyx may have also encountered competition from other carnivorous dinosaurs in the same habitat targeting similar food sources.

For instance, other large theropods or crocodilians may have competed for fish and other resources, prompting violent encounters in certain situations. 

Cultural Significance

In the Cretaceous Spain, a Baryonyx escapes swimming from a brawl with a Hypsilophodon chick in his mouth
In Cretaceous Spain, a Baryonyx escapes swimming from a brawl with a Hypsilophodon chick in his mouth | Alvaro Rozalen via GettyImages

The Baryonyx was a significant paleontological find in England and the world in general.

It was one of the first well-preserved spinosaurid dinosaurs to be identified, providing researchers with valuable anatomical details about the previously elusive dinosaur group.

The fossils included parts of the skeleton, including distinctive skull bones and forelimbs.

These bones shed light on the morphology and unique adaptations of this dinosaur group. 

Baryonyx also provided important scientific insight into the diet of the theropod dinosaurs.

The discovery of fish bones in this dinosaur’s gut confirmed it as the first dinosaur with a piscivorous (fish-eating) diet. 

Life restoration of Baryonyx walkeri based on Scott Hartman's skeletal remains
Life restoration of Baryonyx walkeri based on Scott Hartman’s skeletal remains | Robinson Kunz via Wikipedia CC BY-SA 3.0

Baryonyx was also the first large theropod dinosaur from the Early Cretaceous to be discovered.

As a result, it was nicknamed the “find of the century.”

Before its discovery, the last significant theropod dinosaur found in the United Kingdom was the Eustreptospondylus over a decade earlier. 

The Baryonyx was nicknamed “claws” by the media, a reference to the popular film “Jaws” movie franchise.

Baryonyx was featured in a BBC documentary just a year after its first description was published.

A cast of the skeleton can be seen at the Natural History Museum located in London.


Baryonyx was a spinosaurid theropod dinosaur that lived during the Early Cretaceous period, about 130 million years ago.

Fossils of the dinosaur have been discovered in England, Spain, and other locations across Europe.

Baryonyx was a quadrupedal dinosaur with several unique anatomical characteristics. 

The most notable physical feature is the prominent curved claw which the dinosaur probably used for feeding and self-defense.

Baryonyx may have lived close to river banks and may have waded into shallow water to catch fish.

The discovery of the Baryonyx as the first fish-eating theropod dinosaur ever found provided scientists some insights into the diversity of the theropod dinosaurs, their adaptation to different environments, and the different diets they had. 


Did Baryonyx live in Africa?

No, there’s no fossil evidence that Baryonyx lived in Africa. Fossils of this dinosaur have been recovered from England and parts of Spain but none from the African continent.

What does the name “Baryonyx” mean?

The name “Baryonyx” is derived from Greek words, where “barys” means “heavy” or “strong,” and “onyx” means “claw.” The name refers to the dinosaur’s robust claws, which were a notable feature of its forelimbs.

Who discovered Baryonyx?

The first Baryonyx fossil was discovered by an amateur fossil collector named William J. Walker. He discovered the piece of large claw bone in a clay pit near Ockley, Surrey, in 1983.


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