A team of Chinese, American and Belgian scientists have unearthed a 161-million-year-old dinosaur fossil that shows the animal may have had vibrant, iridescent plumage like that of peacocks and other birds today.
The fossil of the dazzling dinosaur, described in the journal Nature Communications, sheds new light on the evolution of these ancient animals and their relationship with birds.
Caihong juji whose fossil was first found by a farmer in northeastern China, was about the size of a duck and covered in feathers. It is a theropod, like Tyrannosaurus rex but more specifically it is a member of Paraves – a group of dinosaurs whose members include the lineage that gave rise to the birds. Paraves often had feathery plumage, among other characteristics similar to those of birds. ( C. juji is a member of Paraves but was not part of the lineage of birds)
C. juji had a strange mix of characteristics that he called Immediately the attention of Julia Clarke, vertebrate paleontologist at the University of Texas at Austin and one of the main authors of the article.
The dinosaur fossil had short forelimbs but very long feathers in those extremities. He had a huge fantail, similar to that of Archeopteryx his most famous cousin pen. It had asymmetric feathers on part of the tail, which is surprising, because those asymmetric feathers are used to fly and therefore are typically found on wings. And the skull had "lacrimal crests" that looked like bony ridges of eyebrows. they are found in much older dinosaur species, and have not been seen in younger species with "true" feathers
"I immediately saw this combination of features that was really striking and looked really new," Clarke said. "This was an important animal."
More surprises are found in the remains of the feathers themselves. Using scanning electron microscopy, the researchers examined the parts of the cells that contain pigment, called melanosomes. Normally, these pigments basically look black when viewed closely. But for many brightly colored animals, the colors we see are not simply based on the pigment content, but on how those pigments are organized and structured. Different structures can bend light in different ways, resulting in a variety of colors or effects.
In this case, the melanosomes were formed into oval pancakes, a shape seen in the bright plumage of today's hummingbirds.
When iridescence is created, the organization of melanosomes matters, "Clarke said, although the melanosome form is revealing, he said, the true organization of the melanosomes was unclear." We have not yet found them in these fossils. "
Scientists think that C. juji wore iridescent feathers on the head and wings and tail, probably using them as a kind of sexual display, to show off potential partners
The fact that these colorful feather colors existed at the same time as the prominent protuberance of the eyebrows was surprising, said Clarke, it is believed that both are used to show sexually, but since the ridges seemed to disappear in dinosaur species similar to C. juji .
"We think it tells us about the evolution rates of the characters," he explained. "We have a lot of seemingly rapid changes, many different species and combinations of characteristics, and confirms the importance of sexual selection as the engine of some of the traits around that key time period in the origin of the flight of dinosaurs" .
Among the next steps, he added, was to learn more about the lifestyle of this feathered creature. Since it probably was not completely in the air, how exactly did this dinosaur move? Was that tail just to show, or did it somehow help the dinosaur move? How was your ecology?
"There is a set of interesting questions out there that I think are great," he said.
Follow @aminawrite on Twitter for more scientific news and "I like it" Angeles Times Science & Health on Facebook.  MORE IN SCIENCES
Even without pressing blood pressure, diet high in salt coagulates the brain
A ray of light from the drought of California: water conservation reduced energy use and pollution
Erosion is revealing surprising amounts of water ice on Mars