Meet Caihong Juji: The Shimmering Show-Off Feathered Dinosaur

By Gemma Tarlach | January 15, 2018 4:00 am
Here's a pretty thing: newly described feathered dinosaur Caihong juji had iridescent feathers, the earliest such example in the fossil record. (Credit Velizar Simeonovski/The Field Museum)

Here’s a pretty thing: newly described feathered dinosaur Caihong juji had iridescent feathers, the earliest such example in the fossil record. (Credit Velizar Simeonovski, The Field Museum, for UT Austin Jackson School of Geosciences)

Ooh, shiny! The newest dinosaur on the paleoscene is more than a little eye-catching: Researchers believe the duck-sized Caihong juji was rocking iridescent feathers on its head, wings and tail. If it was indeed so fancy, it’s the earliest example in the fossil record of such shimmering finery.

Formally described today, C. juji was discovered in northeastern China, home to many feathered dinosaur finds (but not any tyrannosaurs!). Its name translates from Mandarin as “rainbow with a big crest” and they’re not kidding.

C. juji had a bony crest on top of its head and long, streamer-like feathers, some of which were preserved when the animal was fossilized. And it’s what researchers saw when they took a good look at those feathers that’s so exciting.

Melanosomes, the cellular structures that hold pigment, come in various shapes, which affect how the actual color of the feather is perceived. Platelet- or pancake-shaped melanosomes are found in iridescent feathers such as those of hummingbirds and other fancy sorts.

Based on the imprints of melanosomes in the C. juji fossil, it appears the animal’s head and wings, and parts of its tail, had iridescent feathers. If so, that would make C. juji, which lived 161 million years ago, the oldest known animal with iridescent feathers. By comparing the melanosome imprints in the fossil with those of modern birds, the researchers reconstructed not only the shimmy and shine of C. juji‘s feathers but also the specific colors they believe would have been perceived. In a word: rainbow.

A comparison of melanosomes from C. juji (four images in top row) to those from modern birds with iridescent feathers. (Credit et al)

A comparison of melanosomes from C. juji (top row) with those of iridescent feathers from modern birds. (Credit Hu et al/DOI:10.1038/s41467-017-02515-y)

C. juji is also neat because it appears to have had the oldest known example of asymmetrical feathers, which modern dinosaurs (aka birds) use to steer in flight. C. juji was grounded, however. The feathers were on its tail, not its wings as they are for birds. But the discovery leads to all kinds of intriguing questions about how and why the feathers evolved and what purpose they served.

As for the purpose of C. juji‘s fantastic rainbow fashion, the researchers suspect that, like many birds, its plumage was the equivalent of a “hey, baby” and attracted potential mates. I know I always like a fella with a big crest and rainbow flair.

Today’s research appears in Nature Communications.

CATEGORIZED UNDER: Living World, top posts

Comments (7)

  1. Thomas R. Holtz, Jr.

    “home to many feathered dinosaur finds (but not any tyrannosaurs!)”

    Excuse me? Please remember, the feathered primitive tyrannosauroids Dilong paradoxus and Yutyrannus huali are both from northeastern China.

    Yes, they are both tyrannosauroids (in nearly every analysis so far). And yes, both are unquestionably feathered. Which is why the dogmatic way the Bell et al. article has been reported (in variance with the actual conclusions of the study in question!) is disheartening to see in science communications.

    • GemmaTarlach

      Hi Thomas, The paleontologists who taught me defined tyrannosaur as a member of the genus Tyrannosaurus, and paleontologists I have interviewed in recent years do as well. That’s why I used the word tyrannosaur rather than tyrannosauroid. No feathered members of the genus Tyrannosaurus have yet been found in the fossil record. Much like hominin/hominid, it appears the terms may be evolving. I would be interested in hearing more from you about it. When I started working here at Discover, for example, we used the word “hominid” until I asked a number of paleoanthropologists to help me understand the rise of the word “hominin.” They explained it and our style guide was subsequently updated to use “hominin.” I always appreciate the opportunity to learn something from a credible source. Thanks, Gemma

      • Thomas R. Holtz, Jr.

        Greetings! Informal terms like “tyrannosaur” are unfortunately ambiguous. They might refer just to Tyrannosaurus, or more broadly to all of Tyrannosauridae, or even more broadly to all of Tyrannosauroidea. (See Dave Hone’s recent “The Tyrannosaur Chronicles”, for instance.)

        Furthermore, while it is true no feathers have yet been observed in Tyrannosaurus, the Bell et al. 2017 paper that is the source of much of the news admits that the cannot dismiss the possibility of a feathered dorsum (back) in Tyrannosauridae, or the idea (first put forth in the 1990s) that juveniles may have been fuzzy.

        I hope this helps!

        In any case, Caihong is yet another wonderful dinosaur from China!

        • GemmaTarlach

          I agree Caihong is wonderful, and I thought the analysis of the melanosomes was fascinating. And, as I’ve written before, if an excavation turns up a feathered member of Tyrannosaurus, I will happily write about it (unlike some folks commenting on my post about the 2017 paper, I have no personal stake in the feathered/unfeathered debate!). Until then, however, I’m sticking with “there is no evidence in the fossil record that Tyrannosaurus had feathers.” Your comment inspired me to poll a few paleontologists about the term “tyrannosaur” and based on consensus I may be updating this post once I hear back from them. (As for Hone’s “Tyrannosaur Chronicles,” I don’t think we can hold that up as an example. It is a great read, but any editor would balk at having “tyrannosauroid” in a title!) Thanks, by the way, for having a civil and informative conversation with me on the topic. It’s nice to see that kind of thing can still happen in the comments section of a blog post. 🙂

  2. Mammals are catching up,


  3. Bri An

    society believes what they are told….surprised these dinosaurs didn’t have “flip phones” in their pockets

  4. Anjali Sharma

    Nice! Thank you for the interesting article. I know ScieCoin is creating a new marketspace for data exchange which will be a great breakthrough in science.


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