Chinese archeologists have discovered molecular evidence of the protein keratin in a bird fossil from the Cretaceous Period 130 million years ago, which may provide clues about the color of feathered dinosaurs and early birds.

The research paper by experts with the Nanjing Institute of Geology and Paleontology under the Chinese Academy of Sciences was published by America's Proceedings of the National Academy of Sciences (PNAS) on Tuesday.

Pan Yanhong, a leading researcher with the program, told Xinhua that they discovered the molecular structure of a protein that determines feather color in the bird fossil.

The study shows that these molecular structures are preserved in fossils and are consistent with modern feathers. Researchers hope the study will lead to hypotheses about dinosaur color, behavior, habitat, and physiology.

It was also the oldest molecular evidence found in bird fossils. Previously, the molecular structure of the protein had only been found in fossils dating back some 80 million years.

The bird that experts used in the research is one of the earliest bird fossils found in China. The Cretaceous bird, named Eoconfuciusornis, was discovered in north China's Hebei Province in 2008.