'Missing link' fossil suggests birds ARE descended from dinosaurs after all

Wednesday, May 25, 2011

Fossil-hunters may have found the definitive 'missing link' between dinosaurs and birds, it was revealed today.

The creature is a small plant-eating dinosaur with a toothless beak, stunted arms, and unusual hands.

'Limusaurus inextricabilis' had key features that indicate a half-way point in the transition from dinosaurs to birds.

Dinosaurs vanished from the face of the Earth at the end of the Cretaceous period 65 million years ago. But some experts believe they live on as birds.

Evidence includes the fact two-legged theropod dinosaurs, such as Tyrannosaurus rex had bird-like feet, a bird-like pelvis, and a 'wishbone' typical of birds.

Like birds, they also had hollow bones that may have contained air sacs used in breathing. Some theropods are also believed to have sported primitive feathers.

In addition, preserved protein recently discovered in dinosaur bones appears to be structurally similar to that of modern chickens.

However, there are problems with the dino-bird theory.

Oregon State University recently the thigh bone, which is fixed in birds, stops their lung collapsing, allowing the breathing capacity for flight.

Every other animal that has walked on land, including humans and theropod dinosaurs had a moveable thigh bone.
Also the bird hand, now reduced and embedded in the wing, does not look as if it was derived from a theropod dinosaur hand.

Birds and theropods seem to have retained a different selection of fingers from a five-fingered ancestor.

Until now scientists have believed that while theropods kept the first, second and third fingers, birds held onto the middle three fingers - the second, third and fourth digits.

If birds really are descended from theropod dinosaurs, this should not be the case.

But Limusaurus had hands different from those of any other theropod and may provide a solution to this part of the puzzle.

It had a shrunken first digit alongside more fully developed second, third and fourth fingers.

Source from : http://www.dailymail.co.uk/sciencetech/article-1193689/Missing-link-fossil-suggests-birds-ARE-descended-dinosaurs-all.html

For more information related to dinosaurs, visit rareresource.com.


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