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Ancestor of KingsEarly progenitor of T. rex had a crest

Paleontologists have unearthed remains ofthe oldest known dinosaur of the tyran-nosaur clan. About 160 million years ago,the agile, 3-meter-long predator roamedwhat is now northwestern China. Its fossilsbolster a recent theory about the evolution-ary origins of the fearsome meat eaters thatappeared later.

Dubbed Guanlong wucaii, which inMandarin means “crowned dragon fromthe five-colored rocks,” the newly describedcreature gets its genus name from the dis-tinctive, 6-centimeter-tall crest that runsalong the top of its snout, says James M.

Clark, a vertebrate paleontologist at GeorgeWashington University in Washington, D.C.

The dinosaur shares several traits withTyrannosaurus rex, which lived about 95million years later. Both beasts sportedfront teeth with U-shaped cross sections,nasal bones fused for strength, and anornamented skull.

In the Feb. 9 Nature, Clark and his col-leagues describe two sets of nearly completeremains representing G. wucaii. One set isof an adult estimated to be 12 years old, andthe other is of a juvenile about 6 years ofage. Although both creatures sported a crest,on the younger dinosaur that feature wassmall. In both the adult and the juvenile,the bony structure is largely hollow anddoesn’t appear to be directly connected tothe creature’s nasal passages.

The crest was too fragile to have served anoffensive or defensive function and “onlymakes sense in terms of visual signaling,”says Clark. The structure might have distin-guished one sex of the species from another,been a sign of sexual maturity, or enabledG. wucaii to recognize other members of itsspecies at a distance. Some scientists havespeculated that the bizarre anatomical fea-tures of many other dinosaurs served simi-lar purposes (SN: 8/13/05, p. 103).

Tyrannosaurs were noted for their shortsnouts, sturdy skulls ornamented with knobsand ridges, and puny, two-fingered arms.T. rex stood 4 m tall at the hips, stretchednearly 13 m from its snout to the tip of itstail, and had teeth the size of bananas.

Paleontologists once thought that tyran-

nosaurs had evolved from large predatorsthat lived at the end of the Jurassic period,145 million years ago. However, a decadeago, scientists began to speculate that T. rexand its cousins evolved much earlier, froma line of small, meat-eating coelurosaurs.Fossils show that these creatures sharedmany skeletal features with tyrannosaurs.

The remains of G. wucaii, the first tyran-nosaur relative known to be more than 130million years old, support the latter theory,says Thomas R. Holtz Jr., a paleontologist atthe University of Maryland, College Park.

Not only did G. wucaii share traits withthe tyrannosaurs, but it also hadcoelurosaur-like features, including a rel-atively long snout, bladelike teeth on thesides of its jaws, and long arms with three-fingered, grasping hands, says Holtz.

Although T. rex and the other large, rel-atively recent tyrannosaurs were undoubt-edly the rulers of their ecosystems, G. wucaiididn’t reign in its era. It had to be agile notonly to catch prey but also to escape frompredators about twice its size that lived in thearea, says Clark. —S. PERKINS

Beyond Bar Codes Tuning up plastic radio labels

Electronic labels made from plastic semi-conductors can now pick up and respond toradio signals at a frequency suitable for useon products. At an electronics conference inSan Francisco this week, two Europeanindustrial-research teams described plasticradiofrequency-identification (RFID) pro-totypes with those advanced capabilities.

Although silicon-based RFID tags arealready in wide use—for instance, in so-called smart cards used to pay mass-transitfares—the new developments bring closerthe prospect of RFID tags becoming ascommon as bar codes, or perhaps evenmore so, the researchers say. Besides label-ing consumer products, plastic tags mightmake novel electronic tracking and trans-actions possible, from computer monitor-ing of what’s in the refrigerator to mail rout-ing by means of smart address labels.

To make that leap, tags must becomemuch less expensive than is possible if they’remade of silicon. Hence, the move to plastic.

Until recently, developers of all-plastic tagshave turned out only low-frequency devices.Mainly because of bulky antennas, they’reunsuited for consumer applications. How-ever, some engineers have created compo-nents that operate at high frequencies, suchas the plastic diode reported last year byresearchers in Belgium (SN: 8/13/05, p. 100).

At the 2006 IEEE International Solid-JUST FOR SHOW? Guanlong wucaii, the oldest known species in the tyrannosaur lineage,sported a 6-centimeter-tall crest that ran along the top of its snout.

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