Baryonyx walkeri was a unique theropod dinosaur that lived during the Early Cretaceous period, approximately 130 to 125 million years ago. Its specialized anatomy suggested a diet heavily focused on fish. The geographical locations where its remains were first uncovered provide the most complete picture of this early member of the Spinosauridae family. The primary discovery site was in the United Kingdom, with subsequent evidence found across the Iberian Peninsula.
The Landmark Discovery in England
The foundational discovery occurred in 1983 in Surrey, England, providing the first substantial skeleton of the species. The initial find was made by William J. Walker, an amateur fossil collector exploring the Smokejacks Clay Pit near Ockley. Walker first noticed a massive, curved claw bone protruding from the rock and later retrieved the missing tip and other fragmented bones.
This initial specimen became the holotype for Baryonyx walkeri, named in 1986 in honor of its discoverer. The site, part of the Weald Clay Formation, yielded a remarkably complete, though disarticulated, partial skeleton of a large theropod. A team of paleontologists from the Natural History Museum in London subsequently excavated the quarry, retrieving an extensive collection of bones.
The completeness of the English specimen was particularly noteworthy, as it remains one of the most intact theropod skeletons ever found in the United Kingdom. The recovered material included partial skull bones, vertebrae, ribs, arm bones, and the defining claws. This discovery established the location in southern England as the definitive type locality for the species.
Defining the Dinosaur: Why the Find Was Significant
The analysis of the bones recovered from the Surrey clay pit redefined the understanding of carnivorous dinosaurs. Paleontologists noted the creature’s unusual morphology, particularly the long, low, and narrow snout. This crocodile-like jaw structure, featuring over 96 small, conical teeth, was unlike the robust, deep skulls of typical large theropods.
The species name, Baryonyx, meaning “heavy claw,” references the enormous claw found on the first finger of its hand. This specialized appendage, which measured about 31 centimeters along its curve, was likely used for hunting, possibly to hook or gaff fish. Direct evidence of its diet was found within the rib cage, which contained fossilized fish scales and teeth.
The presence of fish remains provided the first concrete proof of piscivory, or fish-eating, in a large theropod dinosaur. The discovery also showed that the dinosaur occasionally consumed other prey, as bones of a juvenile Iguanodon were found alongside the fish scales. This unique combination of features established Baryonyx as a specialized, semi-aquatic predator.
Other Potential European Sites
While the most complete specimen was found in England, fragmentary remains suggest that Baryonyx was distributed across ancient Europe. The Iberian Peninsula, specifically Spain and Portugal, has yielded several isolated fossils attributed to this genus. These finds indicate the dinosaur’s presence in riverine and coastal environments across Western Europe during the Early Cretaceous period.
In Spain, fragmented bones, teeth, and a maxilla fragment from regions like La Rioja and Castile and León have been referred to Baryonyx. Portugal has also provided teeth and jaw fragments that were initially misidentified as crocodilian but were later recognized as belonging to Baryonyx. These fossils confirm that the distribution of this unique predator extended beyond the original discovery site in the UK.