An ancient bird that lived 120 million years ago had fancy tail feathers like a peacock, a study of fossilised remains shows.
Researchers in China and the US report the discovery of Yuanchuavis kompsosoura, a bird precursor with elaborate feathers that would have helped attract it a mate.
Its remains, including well-preserved tail feathers, were taken from the 120 million-year-old deposits of the Jehol Biota in northeastern China, known as China’s ‘Jurassic Park’.
Y. kompsosoura was a small bird, about the size of a blue jay, but its pair of elaborate tail feathers reached more than 150 per cent the length of its body.
While its tail feathers helped it find a partner, they didn’t make flying very easy, meaning it had to avoid open environments due to the risk of being unable to fly away from predators.
Artist’s impression of the Mesozoic bird Yuanchuavis kompsosoura, as it would have appeared 120 million years ago. The researchers named it Yuanchuavis after Yuanchu, a bird from Chinese mythology. It had a fan of short feathers at the base and then two extremely long plumes
WHAT WAS THE ENANTIORNITHINES?
The enantiornithines was the most abundant and diverse bird group of the prehistoric period.
Almost all retained teeth and clawed fingers on each wing, but were in all other respects like modern birds.
The went extinct with the dinosaurs around 66 million years ago, due to a mass extinction event.
Y. kompsosoura belonged to an extinct group called the Enantiornithines, which looked like modern birds, except they had teeth and clawed fingers on each wing.
Enantiornithines vanished in the mass extinction that wiped out the dinosaurs around 66 million years ago.
The study authors have named this new species named it Yuanchuavis after Yuanchu, a bird from Chinese mythology.
‘We’ve never seen this combination of different kinds of tail feathers before in a fossil bird,’ said study author Jingmai O’Connor, a paleontologist at Chicago’s Field Museum.
‘It had a fan of short feathers at the base and then two extremely long plumes. The long feathers were dominated by the central spine, called the rachis, and then plumed at the end.
‘The combination of a short tail fan with two long feathers is called a pintail, we see it in some modern birds like sunbirds and quetzals.’
According to the researchers, the elaborate ornaments represent the battle between survival and sexual selection at an early point in natural history.
The tail feathers would have made more noticeable to a potential mate, but worse at flying or more noticeable to its predators.
(A) Photograph of Yuanchuavis kompsosoura fossil from the Jehol Biota in northeastern China and (B) line drawing of the remains
Cranial anatomy of the species. Y. kompsosoura belonged to an extinct group called the Enantiornithines, which looked like modern birds, except they had teeth and clawed fingers on each wing
THE JEHOL BIOTA
An ancient ecosystem known as the Jehol Biota existed in north eastern China about 120 million to 130 million years ago.
It consisted of dinosaurs, mammals, early birds, fish, lizards and other creatures, with the red areas highlighted below having thrown up fossils.
The animals lived among coniferous forests and lakes, in the shadow of volcanoes.
Fossils of these animals are found in the Yixian and Jiufotang rock formations, embedded in layers of volcanic material.
‘Scientists call a trait like a big fancy tail an “honest signal”, because it is detrimental, so if an animal with it is able to survive with that handicap, that’s a sign that it’s really fit,’ said O’Connor.
‘A female bird would look at a male with goofily burdensome tail feathers and think, “Dang, if he’s able to survive even with such a ridiculous tail, he must have really good genes”.’
Y. kompsosoura’s tail fossils suggest it lived in dense forest during the Early Cretaceous period (145 million years to 100.5 million years ago).
‘Birds that live in harsher environments that need to be able to fly really well, like seabirds in their open environment, tend to have short tails,’ said O’Connor.
‘Birds with elaborate tails that are less specialised for flight tend to light in dense, resource-rich environments like forests.’
Dense forested environments today are home to some of the most heavily ornamented birds, like birds of paradise (Paradisaeidae).
Likewise, sexual selection has lead to a diversity of colourful and even iridescent tail plumes in modern birds, many of which are aerodynamically costly.
A possible reason for the extinction of enantiornithines along with the dinosaurs around 66 million years ago is that they were mostly forest dwellers.
Dense forested environments today are home to some of the most heavily ornamented birds, like birds of paradise (Paradisaeidae). Pictured, cicinnurus regius, a bird of paradise
Many experts believe the meteor strike that ended the dinosaurs’ reign sparked a global fire storm that destroyed much of the world’s forests.
The discovery of Y. kompsosoura could help answer questions about the birds that survived the big extinction event.
‘Understanding why living birds are the most successful group of vertebrates on land today is an extremely important evolutionary question,’ said O’Connor.
‘Whatever it was that allowed them to be so successful probably also allowed them to survive a giant meteor hitting the planet when all other birds and dinosaurs went extinct.’
The study has been published in the journal Current Biology.
HOW THE DINOSAURS WENT EXTINCT AROUND 66 MILLION YEARS AGO
Dinosaurs ruled and dominated Earth around 66 million years ago, before they suddenly went extinct.
The Cretaceous-Tertiary extinction event is the name given to this mass extinction.
It was believed for many years that the changing climate destroyed the food chain of the huge reptiles.
In the 1980s, paleontologists discovered a layer of iridium.
This is an element that is rare on Earth but is found in vast quantities in space.
When this was dated, it coincided precisely with when the dinosaurs disappeared from the fossil record.
A decade later, scientists uncovered the massive Chicxulub Crater at the tip of Mexico’s Yucatán Peninsula, which dates to the period in question.
Scientific consensus now says that these two factors are linked and they were both probably caused by an enormous asteroid crashing to Earth.
With the projected size and impact velocity, the collision would have caused an enormous shock-wave and likely triggered seismic activity.
The fallout would have created plumes of ash that likely covered all of the planet and made it impossible for dinosaurs to survive.
Other animals and plant species had a shorter time-span between generations which allowed them to survive.
There are several other theories as to what caused the demise of the famous animals.
One early theory was that small mammals ate dinosaur eggs and another proposes that toxic angiosperms (flowering plants) killed them off.