Smile when you call me a dinosaur.

Smile when you call me a dinosaur

If you live in Bavaria and just happen to have a fossil of a skinny, pigeon-sized dinousaur in your basement, you might want to take another look. It could be the next speciment of the rare genus Archaeopteryx, the most primitive known bird--one that is helping scientists link Aves back to their reptilian ancestors. Peter Wellnhofer of the Bavarian State Collection of Paleontology and Historical Geology in Munich reports in the June 24 SCIENCE that he has identified a new Archaeopteryx specimen, which had been found many years ago and misidentified as the dinousaur Compsognathus.

This well-preserved fossil, called the "Solnhofen specimen," joins only five other known Archaeopteryx fossils, all of which come from a unique limestone formation in Bavaria and date back to the upper Jurassic period about 150 million years ago. The last specimen identified by paleontologists also had spent time masquerading as Compsognathus. Found in 1950, this fossil was not correctly identified until the early 1970s.

The new specimen is the largest of all, and there are clear impressions of feathers left in the limestone, Wellnhofer says. These feather imprints are shown as dotted lines in the sketch of the fossil above. The new find may help resolve a debate about correct classification of the smallest specimen. While most scientists have presumed this one to be a juvenile Archaeopteryx, some have suggested it may represent a new species or even a new genus of primitive bird.

Working with colleagues in West Germany and with Yale University's John Ostrom, Wellnhofer has just examined this small specimen though computed axial tomography, better known as CAT scanning. Within the last four years, paleontologists have started to use this advanced X-ray technique, which allows them to peer inside fossilized material without destroying the specimen. This is the first CAT scan of an Archaeopteryx, report the researchers in spring issue of PALEOBIOLOGY. The group has found evidence this primitive animal may have been more advanced than previously thought. In the past, investigators had agreed that in Archaeopteryx, the connecting bone between jaw and skull had a single lobe at the top, a feature shared by most vertebrates but not by birds. However, the CAT scan indicated that two lobes top this bone, suggesting that even the earliest known bird possessed this distinctly avian characteristic.