A fossilized pterosaur headcrest had brightly colored feathers, making it resemble the most ostentatious modern birds. The discovery could rewrite how we imagine coloring not just in pterosaurs, but dinosaurs as well.
While palaeontologists, and palaeontology fans, have debated which dinosaurs had feathers, and what they used them for, the fanciest plumage of the cretaceous may have belonged to their fellow reptiles, the pterosaurs.
Tupandactylus imperator was a large pterosaur famous for its enormous headcrest. In examining a 115 million-year-old specimen from north-eastern Brazil's Crato formation Dr Aude Cincotta of University College Cork and colleagues noticed some tiny feathers around the bottom of the crest. They have announced their discovery in Nature.
“We didn’t expect to see this at all,” Cincotta said in a statement. “For decades palaeontologists have argued about whether pterosaurs had feathers. The feathers in our specimen close off that debate for good as they are very clearly branched all the way along their length, just like birds today”.
The feathers come in two types, short wiry hair-like fibers, and fluffy branched feathers that would do modern birds proud. The fact some pterosaurs had the fibers, technically known as pycnofibres had been established years ago, but more advanced versions have never been confirmed before.
Feathers elsewhere on the body might be for warmth or aerodynamics, but their placement on the headcrest hints at signaling – either to attract mates or ward off rivals. If so, bright colors would be an effective way to enhance their impact, so the authors went looking for melanosomes, or granules of melanin, the most important pigment in modern animals. Although a hundred million years or so underground have removed the color, the team was still able to see that different feather types had differently shaped melanosomes.
“In birds today, feather color is strongly linked to melanosome shape.” said co-author Professor Maria McNamara. “Since the pterosaur feather types had different melanosome shapes, these animals must have had the genetic machinery to control the colors of their feathers. This feature is essential for color patterning and shows that coloration was a critical feature of even the very earliest feathers.” Sadly we can't tell what colors Tupandactylus actually was.
More than 100 pterosaur species are known, so we will need a lot more fossils with this sort of exceptional preservation to know if they all had feathers, let alone different colored ones. However, the authors consider it probable feathers only evolved once on Earth, prior to the point in the Triassic where dinosaurs and pterosaurs diverged. In which case any non-feathered pterosaur, or dinosaur for that matter, had lost them somewhere along the line, making it likely they were the norm, not the exception, given their multiple uses.
Even species that didn't use feathers for signaling or flight may have found downy insulation to their evolutionary advantage. Insulation is a benefit to creatures that produce their own body heat, rather than those that need to obtain their heat from the environment like modern reptiles. Therefore this discovery suggests both pterosaurs and dinosaurs were at least somewhat warm-blooded.
Like historical artifacts, fossils from poorer countries often end up at wealthy institutions with the resources to acquire and analyze them. In this case, however, the scientists saw the T. imperator specimen as so precious it should be considered part of Brazil's natural heritage. With the help of a private donor, they organized for it to be repatriated to its country of origin, hopefully setting precedent for other discoveries of similar significance.