Baryonyx

Natural History Museum in London, where it was examined by Alan J. Charig and Angela C. Milner. 

About 70 percent of the skeleton was later recovered, including the skull. The bones were fossilized in an unnatural position, so the paleontologists reconstructing it placed them on the front feet because these legs were so powerful. The bone structure suggests a massive bulk of muscle ran down the sides of these front legs. It was and is the only known specimen and it seems to have been a juvenile, so the upper limits of its size are still unknown..

Baryonyx was the first carnivorous dinosaur to be discovered in England. It was an unusual theropod with huge foot-long claws on its hands. Most theropods had S-shaped necks, but Baryonyx had a long straight one that was fairly inflexible. The design of its hips and pelvis suggests that it was bipedal for the purposes of walking from place to place. However, its forelimbs were absurdly large for a theropod, suggesting that it also spent much of its time on all fours. It had a long long tail and a low-slung body.

The skull was set at an acute angle, not the 90° angle common in similar dinosaurs. The long jaw was distinctly crocodilian, and had 96 teeth, twice as many as its relatives. Sixty-four of the teeth were placed in the lower jaw (mandible), and 32 large ones in the upper (maxilla). The snout probably bore a small but distinctive crest.

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. Some believe that Baryonyx would sit on a riverbank, resting on its powerful front legs, and then sweep fish from the river with its powerful striking claw. This is the same fishing technique used by modern grizzly bears. The long but low stance and angled head support this theory. Interestingly, Iguanodon bones were found with the Baryonyx skeleton, suggesting that it may have scavenged any extra meat it could find. 

Baryonyx was discovered by William Walker, an amateur fossil hunter, in 1983. He found an enormous claw sticking out the side of a clay pit. He retrieved the specimen, which was surprisingly intact. He took it to the 

Charig and Milner published their description of the type species, B. walkeri, in 1986, and named it after Walker. There is only one specimen of Baryonyx, so there is little debate about classification. There is a similarity to the tetanuran Becklespinax, but there is no evidence that Baryonyx had similar elongated spines on the back of its neck.

Baryonyx was the only known piscivorous (fish-eating) dinosaur until the discovery of the closely-related Suchomimus. It was another crocodile-like fish-eater. Described in 1998, it was placed in the same subfamily (Baryonyichae). It has recently been suggested that Suchomimus tenerensis should be redefined as Baryonyx tenerensis due to similarities in their vertebrae.