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What Color Were Dinosaurs? Now Fossils Have the Answer

By Robyn Broyles, February 22, 2010 16:50



Sinosauropteryx color reconstruction Creative CommonsWhat color were the dinosaurs? Schoolchildren have long been taught that the answer is something we can never know. Color pigments, after all, don't fossilize—or so it was thought.

New dinosaur fossil discoveries in Asia have shown that, in fact, color pigments can fossilize. And these dinosaurs don't disappoint with their coloration:  they came in dramatically patterned technicolor.

For many years, the near-universal consensus among scientists is that birds—and their feathers—evolved from dinosaurs.  All birds have feathers, but some feathered creatures were dinosaurs, not birds.  Feathered dinosaurs belonged to the group of bipedal animals called theropods, along with all other carnivorous dinosaurs.  Sinosauropteryx ("Chinese reptile-wing") was a dinosaur of the early Cretaceous period with primitive feather-like filaments whose color pattern is actually visible on fossils (left image; click to enlarge).

Sinosauropteryx fossil with colors, Creative CommonsPaleontologists at first thought the pattern was an artifact of the fossilization process, but when they took a second look, they discovered they could see the shape of the microscopic pigment-containing structures within the filaments. In living organisms, the shape of these structures, called melanosomes, corresponds to their exact color.  So the scientists determined that Sinosauropteryx had red-brown and white stripes on its tail, and red-brown coloration on its back.

Anchiornis color reconstruction, Creative CommonsSinosauropteryx was only the first dinosaur to appear in full-color in the picture book of science.  Another Chinese fossil from the late Jurassic, Anchiornis, has been added.  Mostly black or dark gray, this animal had a series of bright white stripes on the outer contours of its arms, legs, and tail, and a red brown crest of feathery filaments on its crown.

Pigmented dinosaurs were not the first discoveries of fossilized animal coloration. In the late 1990s, paleontologists found that some well-preserved soft-bodied animals were iridescent.  The shimmering colors of iridescence are produced not by pigments, but by the microscopic physical structure of body coverings. The weird, alien-like animals of the famous 515-billion-year-old Burgess shale were among the first multi-celled animals ever to exist, teeming in the oceans before even the first fish.  Burgess animals such as Wixaxia, Canadia, and Marrella had preserved external structures with diffraction gratings, which produced an iridescent color.  (See Parker, 1998 [PDF].)

 

Wiwaxia corrugata Creative CommonsMarella splendens, Creative Commons

Sinosauropteryx coloration information published in Nature (Zhang et al. 2010).

Anchiornis coloration information published in Science (Li et al. 2010).

Image information

All images in this article are licensed for reuse under the Creative Commons Attribution-Share Alike 3.0 Unported license unless otherwise noted.

Top right:  Reconstruction of Sinosauropteryx based on published images of its coloration.  Image by Matt Martyniuk.

Middle left:  Fossil of Sinosauropteryx with dark pigmentation visible along the back and tail.  Microscopic analysis shows this pigment was reddish brown in life.  Photo by Sam Ose.  (CC) Some rights reserved (Attribution-Share Alike 2.0 Generic).

Middle Right:  Anchiornis reconstruction by Nobu Tamura.

Bottom left:  Wiwaxia corrugata.  The scale-like structures were actually shiny and iridescent, not purple and blue. Image by Sérgio Meira.

Bottom right:  Marrella splendens.  Image by "Ghedo" (username Ghedoghedo, Wikimedia Commons). 

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Tags: science, evolution, dinosaurs, fossils, paleontology, biology, scientific discoveries

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Comments on “What Color Were Dinosaurs? Now Fossils Have the Answer”

Comment #1 Permalink
nice post. thanks.

Posted on February 26, 2010 15:58 by pharmacy technician | pharmacy technician's home page |

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