Caihong juji: This Chinese 'Rainbow Dinosaur' had Iridescent Feathers like Hummingbirds

Wednesday, January 17, 2018

An illustration of a reconstruction of the iridescent dinosaur which had rainbow feathers, named Caihong juji, unearthed in China, is shown in this October 31, 2016 photo released on January 15, 2018. Courtesy Velizar Simeonovski/The Field Museum for the University of Texas at Austin

Newly discovered Caihong juji, a winged dinosaur that roamed what is now China around 161 million years ago, was likely bursting with color—a shock of blue and green around its face, and streaks of orange highlighting its wings and tail. The duck-sized theropod has already been christened with the Mandarin word for “rainbow.”

Microscopic structures in the exquisitely preserved, nearly complete fossil unearthed in Hebei Province indicated that it boasted iridescent feathers, particularly on its head, neck and chest, with colors that shimmered and shifted in the light, like those of hummingbirds.

The discovery “suggests a more colorful Jurassic World than we previously imagined,” said evolutionary biologist Chad Eliason of the Field Museum in Chicago, one of the researchers in the study published in the journal Nature Communications.

Photos and drawings of the incredibly detailed C. juji fossil. Credit: Yu et al., 2018

Using powerful microscopes, the scientists detected within the feathers the remnants of organelles called melanosomes responsible for pigmentation. Their shape determines the color. Caihong’s feathers had pancake-shaped melanosomes similar to those of hummingbirds with iridescent feathers.

Much of its body had dark feathers, but ribbon-like iridescent feathers covered its head and neck. While it possessed many bird-like characteristics, the researchers doubted it could actually get airborne. Its plumage could have attracted mates while also providing insulation.

By examining the fossilized feathers under a microscope, researchers detected structures that hint at possible colors. COURTESY YU ET AL., 2018

Caihong was a two-legged predator with a Velociraptor-like skull and sharp teeth, probably hunting small mammals and lizards. It had crests above its eyes that looked like bony eyebrows. 

Many dinosaurs possessed feathers. Birds evolved from small feathered dinosaurs near the end of the Jurassic Period. Caihong had fuzzy feathers and pennaceous ones, those that look like writing quills. It is the earliest-known creature with asymmetrical feathers, a trait used by birds to steer when flying. Caihong’s were on its tail, suggesting tail feathers, not arm feathers, were first utilized for aerodynamic locomotion.

“It is extremely similar to some early birds such as Archaeopteryx,” said paleontologist Xing Xu of the Chinese Academy of Sciences, referring to the earliest-known bird, which lived 150 million years ago. “Its forelimbs were configured like wings. To be honest, I am not sure what function the feathers have, and I don’t think that you can completely exclude the possibility that the feathers helped the animal to get in the air.”

The shapes of melanosomes can help researchers infer coloration. COURTESY YU ET AL. 2018

Asked what someone might say upon seeing Caihong, University of Texas paleontologist Julia Clarke said, “‘Wow!’ And if they are anything like me, they might want one as a pet. Not suitable for children.”

The dinosaur’s full scientific name, Caihong juji, means “rainbow with a big crest.”

Source: www.reuters.com