Dinosaurs like Diplodocus may have been as colourful as birds

Microscopic structures found in fossilized sauropod skin suggest these giant dinosaurs may have been as brightly colored as some birds.

Tess Gallagher from the University of Bristol, UK, and her colleagues examined sauropod skin fossils believed to be about 145 million years old, collected in 2019 and 2022 from the Mother's Day Quarry in Montana.

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

The researchers took tiny pieces of the fossil's four scales using a scalpel and then examined them with a scanning electron microscope, allowing them to see detail at the cellular level.

According to Gallagher, the skin was preserved in three dimensions, rather than just an imprint. The study also demonstrated the presence of a variety of melanosomes, structures within cells that store melanin, which gives color to skin, hair, eyes and feathers.

“I expected to find at least traces of melanin,” she says. “What we did find was evidence that sauropods could have had a variety of melanosome shapes, which ultimately meant the ability to have a variety of colors.”

Every sample the team studied had melanosomes, and they came in two main types: oblong and disc-shaped. However, it is not yet possible to say for sure what color the skin of these sauropods was, only that the variety of structures suggests many possible shades.

“Diplodocus these would be animals with wonderful texture, with possible color patterns and varied coloration,” Gallagher says.

The closest comparison to disc-shaped structures is the platelet-derived 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 brighter color patterns rather than the gray ones we see in older paleoart.”

Mike Bentonwho also works at the University of Bristol but was not involved in the study, says the shape of the structures described and the way they are preserved suggest they are likely melanosomes.

The researchers are “rightly cautious in their presentation, but this appears to be the first record of flower-bearing melanosomes in a sauropod dinosaur,” he says.

Dinosaur hunting in the Gobi Desert, Mongolia.

Embark on an exciting and unique expedition to find dinosaur remains in the vast Gobi Desert, one of the most famous paleontological hotspots in the world.