It's official: Birds are descended from dinosaurs

Proof positive - if proof were needed - that birds evolved from dinosaurs will be unveiled in Bristol today.

It comes in the shape of five new feathered dinosaur species being presented by legendary Chinese fossil hunter Xu Xing at the Society of Vertebrate Palaeontology's annual meeting.

Xu, dubbed the "Indiana Jones" of palaeontology for his swashbuckling exploits in the deserts of northern China, claims the fossils - including the spectacular four-winged Anchiornis Huxleyi - confirm the bird-dinosaur theory is correct.

"These exceptional fossils provide us with the evidence that has been missing until now. It all fits neatly into place and we have tied up the loose ends." he says.

Anchiornis is officially described in a paper in the journal Nature for the first time today. The type specimen is exceptionally well preserved, with long feathers covering its arms tail and feet, suggesting that a four-winged stage may have existed in the transition to birds.

The idea that birds might have evolved from theropod dinosaurs comes from the striking anatomical similarities between them. Notably the three-toed foot, light hollow bones, and furcula or wishbone. More recent evidence shows that birds and dinosaurs shared behavioural traits like brooding and nesting.

Victorian scientists were well aware of these similarities from the fossil record, but the tipping point came with the discovery of Archaeopteryx in a Bavarian quarry in 1860. With its well developed wings and feathered plumage it was clearly a bird. But it also had claws on its arms and a long bony tail.

Coming so soon after the publication of "On the Origin of Species" (in 1859), the discovery was quickly hailed as the missing link that proved Darwin's ideas about evolution right. Others claimed Archaeopteryx came too late in the fossil record.

The problem is that by plugging an apparent gap in the fossil record Archaeopteryx inevitably created new ones on either side. Until recently, there had been no intermediate fossils showing the steady step by step evolution of dinosaurs into birds either before or after archaeopteryx. A series of discoveries in the 1990's - many of them by Xu Xing - filled the more recent of these gaps. His latest finds, of feathered dinosaurs pre-dating archaeopteryx, complete the picture.

So next time you watch a robin flitting around in the garden, or listen to a blackbird singing, think Allosaurus or even Velociraptor.