Discovery of new species of strange fossil birds in China

Palaeontologists in China have discovered a new species of fossil bird that they say marks a turning point in the evolution of flight, when birds have lost the long tail of dinosaurs, such as Tyrannosaurus and the early bird Archeopteryx, but before they developed the range of feathers on a shortened tail observed in birds flying today.

The 127-million-year-old species they named Jinguofortis perplexus, retains other features of its ancestors dinosaurs, such as claws on the fingers of its wings, a jaw with small teeth rather than a bill and a fused scapular girdle. This last trait is apparently poorly adapted to theft, hence the name "perplexus. "(Learn more about the evolving link between dinosaurs and modern birds.)

Discovered in Hebei Province, northeast of China, Jinguofortis lived in a dense forest environment with scattered lakes, which characterized this early Cretaceous region. Of the size of a modern raven, the species had broad, short wings that could help maneuverability between trees.

"In general, we believe that the modern flying apparatus of living birds has evolved through the gradual accumulation of refinements of their feathers, muscles, and bones for millions of years," Min Wang said. Institute of Vertebrate Paleontology and Chinese Paleoanthropology. Beijing Academy of Sciences, whose team describes the fossil this week in the journal PNAS.

"However," said Wang, "this new bird fossil shows that the evolution of the leak was much more complicated." (See a baby bird of the age of the dinosaurs found in amber.)

Jinguofortis is "one of the most important fossil birds found in recent years," according to Steve Brusatte, paleontologist at the University of Edinburgh, UK, who was one of the editors Chief of the article.

That's because it's one of the oldest and most primitive members of the more modern bird group with shortened tails or pygostyles, and that helps us understand how the first birds changed their tails from their dinosaur tails into the merged, stocky little tails they have today, "says Brusatte. (Here's why the birds may have survived the mass extinction that killed the nonavian dinosaurs.)

But the most interesting aspect of the fossil is perhaps the scapular girdle, according to experts, which resembles that of non-avian dinosaurs rather than birds. Modern birds usually have two bones, scapula and coracoid, which allows them to be flexible in case of theft. But Jinguofortis' the shoulder is fused into a single bone, the scapulocoracoid.

According to Gerald Mayr, an ornithologist and bird evolution specialist at the Senckenberg Research Institute in Frankfurt, Germany, this would be a "very unusual feature" in a flying bird. The two bones generally form an important mobile joint for movement of muscles and wings during flight.

"If this condition is confirmed in future studies, this could inspire new ideas about how these early birds used their wings," Mayr explains, since this feature would probably have hindered the beat. However, Mayr adds, the flying feathers of Jinguofortis have an unusually narrow appearance for a flying bird, and fused shoulder joints are common in species unable to fly, such as ostriches and rheas.

"So one wonders if this animal was actually able to fly, or if it could be an example of a Mesozoic bird unable to fly," he says.

The merged scapular belt prompted the team to consider this possibility, says Wang, but argues that the wings and many other features of the fossil are "indicative of a refined flying ability."

He believes that this odd mixture of features is rather evidence that the evolution of birds is more complicated than previously thought, with the earliest species showing a variety of ways to grow their skeletons and d & # 39; use their flight device.

"All of this shows that birds have not developed all the features they needed to fly in a clear, clear and simple way," says Brusatte. "There was a lot of experimentation in flying styles among early risers."

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