Saturday, 8 November 2008

News Round

Dinosaur Dance Floor: Numerous Tracks at Jurassic Oasis on Arizona-Utah Border

University of Utah geologists identified an amazing concentration of dinosaur footprints that they call "a dinosaur dance floor," located in a wilderness on the Arizona-Utah border where there was a sandy desert oasis 190 million years ago.

The three-quarter-acre site - which includes rare dinosaur tail-drag marks - provides more evidence there were wet intervals during the Early Jurassic Period, when the U.S. Southwest was covered with a field of sand dunes larger than the Sahara Desert.

Located within the Vermilion Cliffs National Monument, the "trample surface" (or "trampled surface") has more than 1,000 and perhaps thousands of dinosaur tracks, averaging a dozen per square yard in places. The tracks once were thought to be potholes formed by erosion. The site is so dense with dinosaur tracks that it reminds geologists of a popular arcade game in which participants dance on illuminated, moving footprints.

From ScienceDaily.

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Dinosaur ancestor of birds may have used feathers to attract mate

A pigeon-sized feathered dinosaur with impressive tail plumage may have been the peacock of its day, scientists have discovered.

The egg-robbing creature, named Epidexipteryx hui, which scientists believe is the oldest known ancestor of birds, lacked the ability to fly.

Scientists believe the feathered dinosaur is the oldest known ancestor of birds
But it did possess four elongated ribbon-like tail feathers which were almost certainly ornamental.

Like the flamboyant peacock, Epidexipteryx may have displayed its tail plumage to attract mates.

Alternatively the long feathers, which might have been brightly coloured, could have been used to intimidate rivals.

Scientists believe Epidexipteryx may be evidence that display plumage evolved before flight feathers.

Describing the find in the journal Nature, the researchers, led by Dr Fucheng Zhang, from the Chinese Academy of Sciences in Beijing, wrote: "Elongate tail feathers (ETFs) are a normal component of the ornamental plumage in extant (living) birds.

"In contrast to other feather types, ornamental plumage is used to send visual signals that are essential to a wide range of avian (bird) behaviour patterns, particularly relating to courtship.

"For example, some experiments have shown that, in some species, males with long tail plumage attract more mates than their short-tailed counterparts.

"It is highly probably that the ETFs of Epidexipteryx similarly had display as their primary function, rather than serving other purposes such as flight or insulation."

From  the Telegraph.

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