Colored Feathers Emerged Among Mammals and Birds During the Dinosaur Age
A melanosome is an organelle found in animal cells that stores and transports melanin, which is a light absorbing pigment protein that is responsible for color and photoprotection of animal tissues. The diversity of melanosomes 150 million years ago has provided scientists with interesting information.
Published in the journal Nature, a study conducted by an international team led by Quanguo Li of the China University of Geosciences in Beijiing sampled ancient and modern melanosomes in hopes of discovering more information regarding the origin and differences of feather color. Melanosomes of brown, black, and gray pigments - ones that make the feathers iridescent - were focused on in the study.
Through the use of a microscope, the researchers examined melanosomes from 181 living creatures and 13 fossilized creatures of the dinosaur era. The researchers found that maniraptors, a group of dinosaurs that scientists believe birds derived from 150 million years ago, contained the same skinny-shaped melanosomes as their modern descendants. Also believed to be the first feathered dinosaurs, maniraptors possessed the first long pinnate feathers and were the first early mammals with hair.
The pigment protein, melanin, is also involved how animals burn energy in their cells, which has led the researchers to believe that the coloring of the birds' and mammals' feathers is also related to metabolism. Melanin is also believed to have increased the rapid spread of the dark pigments among the feathered dinosaurs and early mammals.
The scientists are continuing to find answers regarding the history of melanosomes dating back 150 million years. However, it's going to be difficult to examine the history of pigments for brighter colors, such as yellow and orange. The brown, black and gray colors are of focus right now because the fossils of the creatures examined in the study have more clearly preserved these darker colors.
The ancient fossils were viewed through scanning electron microscopes, a process by which the researchers hope to unearth more historical answers and clues.
To read more about melanosomes in birds and mammals, visit this National Geographic article.