Fossil Feather Melanosomes
photograph courtesy University of Bristol
An international team of researchers reported finding fossilized rod-shaped eumelanosomes, shown here in a scanning electron micrograph, and spherical phaeomelanosomes in 125-million-year-old fossil birds and dinosaurs from China.
Eumelanosomes and phaeomelanosomes are two types of sub-cellular structures called melanosomes that are packed with the dark pigment melanin. A close packing of eumelanosomes from the extinct bird Confuciusornis suggests black was part of its color pattern, the new Nature study says.
Melanosomes are found in abundance within the feathers of living birds, and they have been reported before in fossil feathers.
This is the first time, though, that melanosomes have been found in the fossilized feathers of non-avian dinosaurs—such as Sinosauropteryx and Sinornithosaurus—and in the exquisitely preserved fossil birds from Liaoning Province, China.
Finding melanosomes in dinosaurs shows that the controversial hairlike structures seen in many feathered dinosaur fossils are indeed related to feathers. Analysis of fossilized melanosomes in creatures that lived and died millions of years ago promises to open up exciting new avenues of research and provide a glimpse into the previously unknown world of prehistoric color.