Fossils Show Dinosaurs Ate Birds

Fossils Show Dinosaurs Ate Birds

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 By Mel Morton


microraptor catching its prey

For some time Palaeontologists have suspected that dinosaurs may have eaten birds.

Now, after the recent findings of Dr Jingmai O’Connor and her team at the Chinese Academy of Sciences in Beijing, who discovered a bird skeleton within the fossil of a dinosaur, these theories have been confirmed.

In a recent paper published in the journal Proceedings of the National Academy of Sciences, lead author Dr O’Connor explained the findings and the rarity of a discovery that proves what dinosaurs ate:

“Preserved indicators of diet are extremely rare in the fossil record; even more so is unequivocal direct evidence for predator–prey relationships.”

“Here, we report on a unique specimen of the small nonavian theropod Microraptor gui from the Early Cretaceous Jehol biota, China, which has the remains of an adult enantiornithine bird preserved in its abdomen, most likely not scavenged, but captured and consumed by the dinosaur.”

Dr O’Connor also stated in the paper that the find “provides direct evidence for the dietary preferences of Microraptor and a nonavian dinosaur feeding on a bird.”

Microraptor gui, which means ‘Little Thief’, were small dinosaurs that lived around 125 million years ago during the Cretaceous period.  They would have weighed around 1kg (2.2lb) and been about a metre (3ft) long.

The ‘lizard hipped’ dinosaurs were part of the prehistoric ecosystem known as the Jehol biota in China and are a fairly recent discovery.

In 2003, six specimens of the new species were uncovered in the Liaoning Province in Northeastern China.  The discovery of these fossils created much debate within the community of researchers as they supported palaeontologists long-held beliefs about an evolutionary link between dinosaurs and birds.

At the time, National Geographic writer Hillary Mayell reported on their website:

“The new species, Microraptor gui, provides yet more evidence that birds evolved from dinosaurs, and could go a long way to answering a question scientists have puzzled over for close to 100 years: How did a group of ground-dwelling flightless dinosaurs evolve to a feathered animal capable of flying?”

The evolution of flight divides palaeontologists.  There are two theories.  One being that flight evolved from the ground upwards by a cursorial (ground-living) animal.  While the second theory suggests that flight evolved with gravity and that arboreal (tree-dwelling) animals evolved from gliding into flying.

That’s why the discovery of the bird’s skeleton is important because it provides direct evidence that the dinosaur was an “agile predator” and more tellingly the type of birds Microraptor gui’s ate and how and where they hunted.

“Although this new specimen does not mean without a doubt Microraptor was indeed arboreal or restricted to this environment,” Dr O’Connor has said, “it is suggestive of this hypothesis and contributes new evidence to this important debate.”

The controversy surrounding Microraptor gui’s doesn’t end there.  Since the discovery of the species there have been ongoing discussions on whether they are birds or dinosaurs.  They had four feathered wings, the positioning of which suggests they would have glided rather than flown.

In his article that questions ‘Microraptor gui: Bird or Dinosaur’ Justin Costa Rica writes:  “At first glance, one would think that Microraptor gui would be a bird.”

His reasoning being that “feathers are present covering the whole body, and its forelimbs are modified for flight.”  However, Costa Rica believes that “the evidence supporting Microraptor gui being a dinosaur is overwhelming.”

“Microraptor gui has a digit pattern of 1-2-3, rather than the 2-3-4 seen in birds and possesses the “killer” claw which is characteristic in most basal dromaeosaurs.”

Whether the Microraptor gui was a bird or a dinosaur the undeniable evidence of Dr O’Connor’s findings has proven that it did eat birds.

The skeleton of the bird found within the ribcage of the fossil where the stomach would have been was an Enantiornithes, which means ‘opposite birds.’   There were fifty species of Enantiornithes, who although an extinct group of primitive birds, nowadays have their own Facebook page.

Dr O’Connor and her team say that finding the skeleton in tact indicates that the bird was eaten whole.  They also believe that their discovery shows how the dinosaur hunted as the bird’s feet had the ability to perch, allowing it to live in trees.  This provides further evidence supporting the debate on the evolution of flight.

Others though are not so quick to make such a judgment.  Freya Boardman-Pretty of the New Scientist quotes Luis Chiappe at the Natural History Museum of Los Angeles County, who is concerned about making rash conclusions.

“The fact that Enantiornithes are largely viewed as arboreal animals doesn’t mean that they didn’t frequent the ground – like most living arboreal birds, from parrots to woodpeckers,” Chiappe says.

Whilst the debate amongst palaeontologists continues, the specimen is situated in the collections of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), of the Chinese Academy of Sciences in Beijing.

Relevant Links
Microraptor Fact Sheet
Dinosaur Facts

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