Baryonyx walkeri

Baryonyx was a large, carnivorous theropod dinosaur that lived during the Early Cretaceous period, around 130 to 125 million years ago, in what is now Europe, specifically the United Kingdom and Spain. Recognizable by its long, crocodile-like snout, Baryonyx grew to lengths of up to 30 feet (9 meters) and likely weighed between 1.5 to 2 tons. It belonged to the spinosaurid family, which is known for its semi-aquatic adaptations, and Baryonyx is one of the best-known and earliest members of this group. Its long, slender jaws were filled with conical teeth, ideal for catching slippery prey like fish, which was likely a significant part of its diet. Fossil evidence suggests that Baryonyx had a varied diet, also feeding on small dinosaurs and possibly even large prey, such as the herbivorous Iguanodon, as indicated by its fossilized remains found in the stomach cavity of one individual.

The most striking feature of Baryonyx was its large, hook-shaped claw on the first digit of each hand, which could have been used for grasping prey or possibly for defense. Despite its relatively slender build compared to some other theropods, Baryonyx was a powerful predator, capable of swift movement on land and possibly adept at swimming or wading in water, much like modern-day crocodiles. Its semi-aquatic lifestyle is further supported by its long, muscular tail, which would have aided in swimming, as well as the structure of its teeth, well-suited for grasping rather than slicing, indicating a feeding behavior more in line with fish-eating animals.

The discovery of Baryonyx in the 1980s was significant because it provided crucial evidence for the hypothesis that spinosaurids were not solely land-based predators but had adaptations for a more aquatic or semi-aquatic lifestyle. As one of the first dinosaur fossils to show such features, Baryonyx helped reshape our understanding of the diversity of theropod feeding behaviors and habitats during the Early Cretaceous period.