'Rainbow dinosaur' had iridescent feathers like a hummingbird

There's not a pot of gold atthe end of the rainbow. There's an iridescent dinosaur.

Scientists on Monday announced the discovery of acrow-sized, bird-like dinosaur with colourful feathers fromnortheastern China that lived 161 million years ago during theJurassic Period.

They named it Caihong, the Mandarin word for rainbow.Microscopic structures in the exquisitely preserved, nearlycomplete fossil unearthed in Hebei Province indicated that itboasted iridescent feathers, particularly on its head, neck andchest, with colours that shimmered and shifted in the light, likethose of hummingbirds.

The discovery "suggests a more colourful Jurassic World thanwe previously imagined," said evolutionary biologist Chad Eliason of the Field Museum in Chicago, one of the researchersin the study published in the journal Nature Communications.

Using powerful microscopes, the scientists detected withinthe feathers the remnants of organelles called melanosomes
responsible for pigmentation. Their shape determines the colour.

Caihong's feathers had pancake-shaped melanosomes similar to those of hummingbirds with iridescent feathers.

Not for flying

Much of its body had dark feathers, but ribbon-likeiridescent feathers covered its head and neck. While itpossessed many bird-like characteristics, the researchersdoubted it could actually get airborne. Its plumage could haveattracted mates while also providing insulation.

Caihong was a two-legged predator with a Velociraptor-likeskull and sharp teeth, probably hunting small mammals andlizards. It had crests above its eyes that looked like bonyeyebrows.

Many dinosaurs possessed feathers. Birds evolved from smallfeathered dinosaurs near the end of the Jurassic Period. Caihonghad fuzzy feathers and pennaceous ones, those that look like writing quills. It is the earliest-known creature withasymmetrical feathers, a trait used by birds to steer whenflying. Caihong's were on its tail, suggesting tail feathers, not arm feathers, were first utilized for aerodynamiclocomotion.

"It is extremely similar to some early birds such asArchaeopteryx," said paleontologist Xing Xu of the ChineseAcademy of Sciences, referring to the earliest-known bird, whichlived 150 million years ago. "Its forelimbs were configured likewings. To be honest, I am not sure what function the feathershave, and I don't think that you can completely exclude thepossibility that the feathers helped the animal to get in theair."

Asked what someone might say upon seeing Caihong, Universityof Texas paleontologist Julia Clarke said, "'Wow!' And if theyare anything like me, they might want one as a pet. Not suitablefor children."

The dinosaur's full scientific name, Caihong juji, means"rainbow with a big crest."