A Dinosaur With Guts

By MICHAEL D. LEMONICK

The Pietraroia limestone beds near Naples, Italy, are celebrated for the exquisite fossils they've yielded up since the early 1800s--gorgeously preserved specimens of prehistoric fish and a few birds. No dinosaurs, though. While the rocks date back some 110 million years, smack in the middle of the terrible lizards' reign, not a single dinosaur bone had ever been found there. As far as amateur paleontologist Giovanni Todesco knew, that dismal record was still intact even after he unearthed a 9-in.-long specimen about a decade ago. The nearly complete skeleton, missing only its tail and the lower part of its legs, looked as if it belonged to a bird, and that's what Todesco assumed it was.

But a couple of years later, he went to see Jurassic Park. As he viewed its distinctly birdlike velociraptors, it suddenly dawned on Todesco that he'd better get a second opinion. Sure enough, when he showed his little critter to experts at a paleontology museum, it turned out that he had not only the first dinosaur ever found in Pietraroia but the first found anywhere in Italy.

That fact alone made the discovery important. But on closer examination, scientists found something even more remarkable: not only had the mini-dino's bones survived (save those of the lower legs and tail), but so, evidently, had some of the tissues inside. As described in the current issue of the journal Nature, the dinosaur, almost certainly a baby, has significant amounts of its intestines and liver still intact, along with muscles and the cartilage that once housed its windpipe--"details of soft anatomy never seen previously in any dinosaur," write Italian paleontologists Cristiano Dal Sasso and Marco Signore.

As a result, the newly named Scipionyx samniticus may end up telling paleontologists more about the anatomy of theropods--a group of two-legged dinosaurs--than they could ever learn from bones alone. The group, which includes Tyrannosaurus rex as well as velociraptors, is considered by many to comprise the direct ancestors of modern birds. Having the internal organs in hand could help support--or torpedo--that connection. Already, in fact, some scientists are suggesting that the position of the liver indicates an internal structure more like a lizard's than a bird's, undercutting the dinosaur-bird link. Its breastbone, on the other hand, says paleontologist Mark Norell of the American Museum of Natural History, could hardly be more birdlike.

No matter Scipionyx's evolutionary significance, its aesthetic significance is clear. "It really is a beautiful specimen," says Norell. On that, he gets no disagreement from anybody.