Dinosaurs like Diplodocus may have been as colourful as birds

Microscopic structures observed in the fossilized skin of a sauropod suggest that these giant dinosaurs may have had colors as vibrant as those of some birds.

Tess Gallagher of the University of Bristol, UK, and colleagues examined sauropod skin fossils around 145 million years old, collected in 2019 and 2022 from Mother’s Day Quarry in Montana.

Although the fossils could not be positively identified, it is believed that they probably came from Diplodocus.

The researchers removed tiny pieces of the fossils’ four scales using a scalpel, then studied them with a scanning electron microscope, allowing them to see details at the cellular level.

The skin was preserved in three dimensions, rather than just an impression, Gallagher explains. The study also highlighted the presence of various melanosomes, structures inside cells that store melanin, creating color in skin, hair, eyes and feathers.

“I expected to find at least traces of melanin,” she says. “What we found was evidence that sauropods could have had various shapes of melanosomes, which ultimately means the potential for diverse colors.”

Each specimen the team studied had melanosomes, divided into two main types: oblong and disc-shaped. However, it is not yet possible to say exactly what colors the skin of these sauropods would have been – only that the variety of structures suggests multiple possible shades.

“Diplodocus would have been remarkably textured animals, with potential color patterns and diverse colors,” says Gallagher.

The closest comparisons that can be made to disc-shaped structures are the platelet melanosomes found in the feathers of modern birds. Gallagher says this could be evidence that Diplodocus had the potential to create a variety of colors using their melanosomes. “These animals might have more striking color patterns, instead of being gray like we see in ancient paleoart.”

Mike Benton, who is also at the University of Bristol but was not involved in the research, says the shape of the structures described and the way they are preserved mean they are likely melanosomes.

The researchers are “rightly cautious in their presentation, but it appears to be a possible first record of colored melanosomes in a sauropod dinosaur,” he says.

Dinosaur hunting in the Gobi Desert, Mongolia

Embark on an exhilarating, one-of-a-kind expedition to discover dinosaur remains in the vast wilderness of the Gobi Desert, one of the most famous paleontological hotspots in the world.