Keratin and melanosomes preserved in 130-million-year-old bird fossil

Eoconfuciusornis. Credit: Dr. Xiaoli Wang


Eoconfuciusornis, crow-sized primitive birds that lived in what is now China around 130 million years ago, are the earliest birds to have a keratinous beak and no teeth, like modern birds. Previous studies argued that the of these and other ancient birds and dinosaurs preserved small, round structures interpreted to be melanosomes - pigment-containing organelles that, along with other pigments, give feathers their color. However, without additional evidence, it was not possible to prove that these structures weren't just microbes that had coated the feather during decomposition and fossilization.


"If these small bodies are melanosomes, they should be embedded in a keratinous matrix, since feathers contain beta-," Schweitzer says. "If we couldn't find the keratin, then those structures could as easily be microbes, or a mix of microbes and melanosomes - in either case, predictions of dinosaur shading would not be accurate."

Pan, Schweitzer and their team used both scanning and transmission to get microscopic details of the feather's surface and its internal structure. They also utilized immunogold labeling - in which gold particles are attached to antibodies that bind to particular proteins in order to make them visible in electron microscopy - to show that filaments within the feathers were keratin.


"This study is the first to demonstrate evidence for both keratin and melanosomes, using structural, chemical and molecular methods," says Pan. "These methods have the potential to help us understand - on the molecular level - how and why feathers evolved in these lineages."

The work appears in Proceedings of the National Academy of Sciences.

Explore further


More information: Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1617168113
Citation: Keratin and melanosomes preserved in 130-million-year-old bird fossil (2016, November 21) retrieved 5 April 2020 from https://phys.org/news/2016-11-keratin-melanosomes-million-year-old-bird-fossil.html

Feedback to editors

User comments