Sunday, October 26, 2008

Early Feathers for Display?

A recent fossil discovery indicates that the earliest dinosaur feathers, worn by Epidexipteryx hui of the Jurassic period, were for show rather than flight.

The remains date back to 152 million to 168 million years ago, making the newfound creature slightly older than Archaeopteryx, the most primitive known bird....

Like other avialans—birds and their closest dinosaur relatives—Epidexipteryx is a theropod, a group of two-legged animals that includes Tyrannosaurus rex.

Researchers think the pigeon-size Epidexipteryx might have used its plumes as flashy ornaments, since it was mostly covered in short feathers that lack the structure necessary for flight.

"For example, [the feathers] could potentially have played a role in displays intended to attract a mate, scare off a rival, or send a warning signal to other individuals of the same species," said study co-author Fucheng Zhang, a paleontologist at the Chinese Academy of Sciences in Beijing.

"This is very exciting indeed, since it gives us a window into a stage of avialan history just preceding the appearance of the classic 'first bird,'" Zhang said.

"It shows that the use of feathers for visual communication—as opposed to other functions such as insulation and flight—was a very early development."
Unfortunately the article spends too much time playing up the "bizarre" nature of this dinosaur's anatomy, which does not sound bizarre at all. (Wow, a theropod with teeth?!? Who would have guessed?!?) It does quote at least one palaeontologist who thinks that feathers served to help Epidexipteryx run faster. I do not see these functions as necessarily being in opposition to each other, since feathers on modern birds often serve both functions. (Consider the case of a northern cardinal. Are its feathers for show, for flight, or for insulation?) In any case, it is an interesting find.