Dinosaurs went from drab to colorful fab just before 150 million years ago, according to a study published in the latest issue of the journal Nature.
The "Wizard of Oz"-type moment in evolution appears to coincide with the emergence of feathers.
Researchers determined this after studying pigment-containing organelles known as melanosomes. These specialized structures within cells in living organisms contain melanin, which is the most common light-absorbing pigment found in animals.
"Black, brown and grey colors are melanin-based," co-author Julia Clarke told Discovery News. "In birds, melanin-based colors include a slightly larger range of reddish brown, brown, black, grey, black and many forms of iridescence."
Clarke is an associate professor at the University of Texas at Austin's Jackson School of Geosciences. She and her colleagues compared the melanosomes of 181 diverse living animals, including birds, mammals and reptiles, as well as 13 fossil specimens and all previously published data on this subject.
Before it was determined that diversity in the shape and size of melanosomes is associated with the evolution of melanin-based color in non-avian dinosaurs, birds and mammals. This diversity in dinos happened suddenly, just as small, meat-eating maniraptoran dinosaurs were evolving feathers, the study found.
"This shift is not seen close to the origin of dinosaur 'fuzz' or 'protofeathers,' but is only associated with feathers," Clarke said. "The shift seems abrupt and occurs before the origin of anything we would call avian flight."
While she and her team are not sure why dinosaurs experienced such a color explosion, Clarke said the dramatic change could have facilitated mate selection. Just as pretty, colorful birds today catch our eye, colorful exteriors would have probably grabbed the attention of non-flying dinosaurs and literal 'early birds' seeking sexual partners.