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Spinosauridae

Baryonyx walkeri bah-RY-on-ix

"Heavy claw"

Baryonyx silhouette
You 1.8 m (5.9 ft) tall
Baryonyx 9 m (29.5 ft) long
as long as 6 people standing fingertip to fingertip
silhouette · Ivan Iofrida (CC-BY) via PhyloPic
Length
9 m (29.5 ft) — About 9 m long, ~1.7 tonnes — with a 30 cm thumb claw.
Period
Early Cretaceous (130–125 Mya)
Place
Europe · England · Spain
Food
Piscivore (fish-eater) — Fish primarily — the first specimen had fish scales preserved in its stomach.
Clade
Spinosauridae Dinosauria Saurischia Theropoda Crocodile-snouted fish-eaters with sail or hump.

A fish-eating theropod with a gharial-like snout and a huge curved claw on each hand.

Baryonyx is one of the few dinosaurs we know ate fish, because the first skeleton ever found had partially digested fish scales preserved inside its ribcage. Long crocodile-like jaws and giant hooked thumb claws made it well-suited to scooping fish out of Cretaceous rivers in what is now southern England.

More about Baryonyx

Discovery

Named by Alan J. Charig and Angela C. Milner · 1986 · Smokejack Clay Pit in the Weald Clay Formation near Ockley, Surrey, England

In January 1983 the plumber and amateur fossil collector William J. Walker found a large claw in the clay pit, then returned weeks later and recovered the missing tip after an hour of searching. Natural History Museum staff and volunteers later excavated the skeleton in 54 blocks over a three-week period in 1983.

From Ancient Greek barús, meaning "heavy" or "strong", and ónux, meaning "claw", a nod to the very large claw on its first finger.

Was the discovered animal fully grown?
The holotypeThe single specimen that formally defines a species' name. (NHM R9951) may not have been mature. Skull and vertebral elements do not appear to have fused, which suggests the individual was still growing and the adult may have been much larger, as seen in some other spinosaurids. On the other hand, its fused sternum hints that it may have been mature.
How is Baryonyx related to Spinosaurus?
Its affinities were unclear at discovery. By 1988 Gregory S. Paul saw Spinosaurus and Baryonyx as similar, while in 1990 Charig and Milner dismissed close spinosaurid links, and by 1997 accepted the families were related but resisted merging the names. The relationship was worked out gradually rather than settled at once.

What we know

  • Stomach contents of the type specimen included fish scales and a juvenile Iguanodon bone.
  • Long, narrow jaws with conical teeth — convergent with modern crocodilians.
  • A 31 cm hooked thumb claw on each hand, possibly for hooking fish.
  • First spinosaurid known well enough to reconstruct — relatives include Spinosaurus and Suchomimus.

What we guess

  • Whether it caught fish by wading and hooking, or by ambushing them from the bank.
  • Whether the Iguanodon bone in the stomach was active hunting or scavenging.
  • Whether Baryonyx had a small sail like Spinosaurus — vertebrae suggest a low ridge.