Fossil claw unearths a new family tree.

Fossil claw unearths a new family tree

When Dr. Morbius's invisible creature attacks a spaceship crew in the film "The Forbidden Planet," the first clue to its appearance comes from a plaster cast of a large, ominously curved claw. A similar claw found south of London three years ago by an amateur fossil hunter has sparked the first description of an intriguing family of dinosaurs, which were most likely fish-eaters despite their ferocious appearance.

The 12-inch claw, found by William J. Walker (SN: 7/30/86, p.70), directed scientists to a well-preserved skeleton of a large theropod (meat-eating) dinosaur, recently dubbed Baryonyx walkeri by paleontologists Alan J. Charig and angela C. Milner at the British Museum of Natural History in London. They report the results in the Nov. 27 NATURE.

Thirty feet long, 15 feet tall on its hind legs and weighing nearly 2 tons, the clawed B. walkeri with its crocodile-like head must have been "fearsome," Charig told SCIENCE NEWS. He says the dinosaur deserves its own family (Baryonychidea, meaning "strong claw") on the basis of its "enormously elongated snout," twice the usual therapod number of teeth, and powerful forelimbs with at least one large claw. The vicious Tyrannosaurus rex had tiny forelimbs and much shorter claws on its hindlimbs.

"As far as Europe and Britain go," says Charig, "I would say it's the best find of the century. It is not a 'missing link,' but suggests a separate line of [dinosaur] evolution. One thing it demonstrates more than anything else is the incompleteness of the dinosaur fossil record. There must have been thousands or millions of them and this is the only one we've found."

Earlier this year, Charig met with other dinosaur experts, looking for someone with similar fossils. But no one had seen anything like the yet-to-be-named dinosaur. One of those experts, Michael Brett-Surman of the National Museum of Natural History in Washington, D.C., told SCIENCE NEWS that "if someone has just drawn a family tree of meat-eaters, they'll need to throw it in the trash.... [The dinosaur] is a hodgepodge of very advanced and very primitive characteristics at the same time."

Charig says more recent evidence indicates the dinosaur is 115 million years old, rather than the reported 124 million. Nevertheless, he says, it is still the first large, "reasonably complete" theropod ever found in the Lower Cretaceous rock layer anywhere in the world. But it will be three to four years, he says, before the dinosaur -- nicknamed "Claws" -- will be totally reconstructed for museum viewing.