Baryonyx

Baryonyx Temporal range: Early Cretaceous, 130–125 Ma PreЄ Є O S D C P T J K Pg N ↓
Reconstructed skeleton, Natural History Museum, London
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Family:	†Spinosauridae
Genus:	†Baryonyx Charig & Milner, 1986
Species:	†B. walkeri
Binomial name
Baryonyx walkeri Charig & Milner, 1986

Baryonyx (/ˌbæriˈɒnᵻks/) is a genus of theropod dinosaur which lived in the Barremian stage of the early Cretaceous Period, about 130–125 million years ago. The holotype specimen was discovered in 1983 in Surrey, England, and the animal was named Baryonyx walkeri in 1986. The genus name, Baryonyx, means "heavy claw" and alludes to the animal's very large claw on the first finger; the specific name (walkeri) refers to its discoverer, amateur fossil hunter William J. Walker. Fragmentary specimens were later discovered in other parts of the United Kingdom and Iberia. The holotype specimen is one of the most complete theropod skeletons from the UK, and its discovery attracted media attention.

Baryonyx was between 7.5 and 10 m (25 and 33 ft) long and weighed between 1.2 and 1.7 t (1.3 and 1.9 short tons), but the holotype specimen may not have been fully grown. It had a long, low snout and narrow jaws, which have been compared to those of a gharial. The tip of the snout expanded to the sides in the shape of a rosette. Behind this, the upper jaw had a notch which fitted into the lower jaw (which curved upwards in the same area). It had a triangular crest on the top of its nasal bones. Baryonyx had many finely serrated, conical teeth, with the largest teeth in front. The neck was less curved than that of other theropods, and the neural spines of its dorsal vertebrae increased in height from front to back. It had robust forelimbs, with the eponymous first-finger claw measuring about 31 cm (12 in) long.