One of my first posts was about a discovery that was previously thought impossible to answer – what was a dinosaur’s body temperature? Another ‘impossible to answer’ question about dinosaurs has recently been answered telling us what colour dinosaurs were.
If all your knowledge of what dinosaur’s appearance comes the Jurassic Park movies then you might not know that some dinosaurs had feathers. Most of these were theropods, a group of two legged dinosaurs that includes the movie stars tyrannosaurus, spinosaurus and velociraptor. Only some theropod fossils have been found with evidence of feathers, but they are from such varied sections of the group that it is thought that once evolved, all subsequent theropods down the evolutionary line would have had some signs of feathers. While there is little proof of what, if any, feathers tyrannosaurus had, velociraptor fossils show that they definitely had feathers.
Birds are thought to have evolved from dinosaurs similar to velociraptor. In fact, most palaeontologists consider birds to just be dinosaurs which were able to survive the mass extinction event that affected their cousins. What we simply call dinosaurs are referred to as ‘non-avian dinosaurs’ by paleontologists to distinguish them from the dinosaurs that live on as modern day birds.
But while feathers are cool and all, this is supposed to be a story about what colour dinosaurs were.
Many specimens of feathered dinosaur have been found in China over the last decade. One of these was microraptor, a crow-sized dinosaur with a long, thin tail and ‘wings’ on both its arms and legs that, while not able to provide flight, were probably used to glide from tree to tree. The microraptor fossil was so well-preserved that scientists were able to isolate the microraptor’s melanosomes, the microscopic structures inside the feathers that gave them their colour. By comparing the melanosomes in the fossil feather with melanosomes found in the feathers of modern birds, the scientists were able to work out what colour microraptor was.
The results published last week show that microraptor had iridescent blue-black feathers, a feature shared by many modern birds and often used for mating displays. Microraptor also had two long feathers that poked out from the end of its long thin tail. These would have served no use for flight and it has instead been suggested that they were also used for mating displays.
This finding not only reveals what colour microraptor, but also gives us an insight into its lifestyle. Iridescent feathers are only seen in modern birds which are active during the day. It is therefore unlikely that microraptor was nocturnal, as previously thought. It also suggests that feathers may have evolved for the purpose of display as much as any aerodynamic or warmth advantages that they give.
The fossil of microraptor was an extraordinary find and scientists are continuing to make new discoveries about the lives of it and all those other incredible creatures that we call dinosaurs.
Li, Q., Gao, K.-Q., Meng, Q., Clarke, J. A., Shawkey, M. D., D’Alba, L., et al. (2012). Reconstruction of Microraptor and the Evolution of Iridescent Plumage. Science, 335(6073), 1215-1219. doi:10.1126/science.1213780