Vinther and his colleagues continue to search for more clues about coloration. By studying the structures of melanosomes' arrangement in more recent feathers, they were able to deduce when feathers would have iridescence, lending another level of sheen, and even purples, blues and greens to some surfaces. In a 2009 paper in Biology Letters, the team described evidence of iridescence they found on fossilized middle Eocene epoch feathers based on these structures, but older bird and dinosaur feathers have yet to yield any shiny clues.
Given these organelles' prevalence, their discovery in fossilized feathers will likely open the door to a rush of new coloration studies. "We can definitely take this to look at skin, as well," Vinther says. As Benton noted, however, although the pigmentation is widespread in reptile and fish scales today, it is unusual to find remnants of organic material in dinosaur fossils. What we know about their skin is generally deduced from imprints left in surrounding material, which would not contain the organelles needed to predict coloration.
In the meantime, even if only the wings and tails of certain feathered dinosaurs and early birds can be colored in, it will help researchers deduce much more about extinct animals' ecology and behavior—and also about other physiological details such as vision. As Vinther notes, "If you do find spectacular colors in these animals, then you know they had an ability to see more colors than just black and white."
Beyond coloration, the presence of these melanosomes in early Cretaceous dinosaurs helps to confirm the presence of protofeathers in some dinosaurs, which some have argued were simply connective tissue. The Sinosauropteryx that they studied, one of the earliest Sinosauropteryxs to have featherlike structures had, what Benton described as "a very clear rim of feathers running down the head, down the back and along the tail."
These adornments were not feathers in the modern sense, such as those found on modern turkeys and peacocks. "These are very simple structures," Benton said. "They're sort of bristles" which were four to 10 millimeters long. But these unassuming bristles "really are feathers," he said.
"In terms of the sequence of evolution of feathers, we can now say they start as simple bristles," Benton noted. If this is the case, it would support the idea that the structures that were to become feathers originally developed not for flight but rather for display purposes. "That's a display function," Benton said. "It's clearly not for flight."