Name: Baryonyx walkeri
Name Meaning: Heavy Claw; named after William Walker
Age: Early Cretaceous (Barremian)
Location: Southern Britain
Baryonyx walkeri was a large theropod from the Early Cretaceous of the UK, discovered in Smokejacks Pit, near Ockley, Surrey, in 1983. The first fossil found of this species was its signature claw, but after further excavation, more of the animal was found, including parts of the skull. This holotype specimen is currently housed in the Natural History Museum in London, and it is the most complete spinosaurid ever discovered.
After William Walker initially discovered the claw in January 1983, he soon realised that it was broken. Returning to the pit, he found the tip along with a handful of other bones. These remains were taken to the Natural History Museum, where they were analysed by Alan Chairg and Angela Milner, who realised the bones were from a large theropod. A team of eight palaeontologists and some volunteers returned to the pit in May 1983 and excavated two tonnes of rock containing the rest of the specimen.
Baryonyx was, like other spinosaurs, a piscivore. The method by which it captured its prey was part of some debate when it was discovered. Charig and Milner originally stated that the large claws present on its forelimbs were used like those of grizzly bears to ‘gaff’ fish from the water. This was disputed in 1987 by Kitchener, who suggested that the long snout and large claws meant that it was a scavenger. The claws, he suggested, were for opening carcasses, and then the long snout allowed Baryonyx to explore the body cavity.
The debate was put to rest when, in 1997, Charig and Milner published on remains found in the stomach cavity of Baryonyx. Inside they found acid-etched fish scales and teeth from a common fish, Lepidotes. Alongside these, they also found acid-etched remains of a young Iguanodon. This evidence, alongside the narrow jaws with semi-conical teeth and the large claw, indicates that Baryonyx was a piscivore. It is likely that it captured fish similarly to modern crocodiles, using its front teeth to grasp and hold its prey before swallowing whole. If the fish was too large to swallow whole, the claws could then be used in order to break it up into smaller parts. The presence of Iguanodon bones in the stomach also indicates that Baryonyx likely hunted small-to-medium terrestrial animals, potentially using its claws, rather than its jaws, to kill these prey animals.
Baryonyx’s home in the Early Cretaceous was along shorelines and within floodplains that covered the south of the UK and stretched across to Europe. The Wealden Group of the UK documents this environment and shows a diverse dinosaur community was present, including ornithopods such as Iguanodon, sauropods like Eucamerotus, and thyreophorans such as Polacanthus. Other theropods, such as Neovenator, also shared the territory, but they would have hunted the larger terrestrial animals, limiting competition.
Baryonyx was an important find, both for understanding UK dinosaurs and their communities, but also has global implications for spinosaurids as a whole. Being interviewed in 1986, Charig remarked that ‘as far as Europe and Britain go, I would say it’s the best find of the century’, and this author is inclined to agree.
 Baryonyx walkeri by Jack Wood.
 A line drawing of the holotype specimen BMNH R9951. Artwork by Charig and Milner (1997).
Information References and Further Sources
 Charig, A. J., and Milner, A. C. (1986). ‘Baryonyx, a remarkable new theropod dinosaur’, Nature, 324, pp. 359-361. Accessed 6th May 2021. Click Here.
 Charig, A. J., and Milner, A. C. (1997). ‘Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey’, Bulletin of the Natural History Museum (Geology), 53(1), pp. 11-70. Accessed 6th May 2021. Click Here.
 Edwards, D. D. (1986). ‘Fossil claw unearths a new family tree’, Science News, 130 (23), pp. 356. Accessed 6th May 2021. Click Here.
 Hone, D., and Holtz, T. R. (2017). ‘A Century of Spinosaurs – A Review and Revision of the Spinosauridae with Comments on Their Ecology’, Acta Geologica Sinica, 91 (3), pp. 1120-1132. Accessed 6th May 2021. Click Here.
 Kitchener, A. (1987). ‘Function of Claw’s claws’, Nature, 325, pp. 114. Accessed 6th May 2021. Click Here.