Crowned Dragon Dinosaur Unearthed
Posted on February 13, 2006
New Scientist reports that Guanlong, the great-grandfather of the T. rex has been unearthed in China.
"Considering that Guanlong is a tyrannosaur, its crest is really amazing," Xu told New Scientist. "In this regard, Guanlong's exaggerated, complex crest is similar to the sexually selected ornaments widely present in extant and extinct vertebrates."The article said the dinosaur had an "unusual prominent nasal crest on its head" which was possibly used for attracting a mate. An IHT article said the crest finding was a big surprise.The near-complete fossils reveal an unusual combination of primitive features retained from ancestral dinosaurs and derived features that had been thought to evolve later. That means the similarities of later dinosaurs may show evolution converging on common traits rather than the common ancestry that palaeontologists often assume.
Tyrannosaurs grew to gianthood late in their history. "They put in the early part of their history as secondary predators," in the shadow of allosaurs and spinosaurs, says Tom Holtz of the University of Maryland in College Park, US. Nine-metre giant tyrannosaurs did not appear until about 80 million years ago, just 15 million years before an asteroid impact ended the reign of the dinosaurs.
The presence of a crest on the Guanlong adult's head was a complete surprise, Clark said, showing that there was "clearly still much more to be learned about early tyrannosaurs."There is a great deal of debate on the color of dinosaurs but it makes you wonder if the nasal crest had color or even vibrant colors.Researchers said the crest was about as thin as a pancake and only two and a half inches, or 6.4 centimeters, high. It appeared to be filled with air sacs and reminded the paleontologist of the ornamental features found on some living birds, like cassowaries and hornbills.