The next big dinosaur discovery is here. A team of Korean paleontologists recently found a small set of dinosaur tracks that included a layer of fully intact skin. The group was thrilled: this discovery is one-of-a-kind and may provide researchers will new knowledge and deeper understanding of these ancient beasts.

These Korean dino tracks were made by a tiny theropod, the Minisauripus, which was about the size of a modern-day blackbird. While there have been ten different Minisauripus fossil discoveries, this was the first to contain any traces of skin, and every small track in this unusual fossil was covered in a well-preserved layer of fingerprint-like skin. The traces of skin cells found on these tracks are unlike the trace amounts of skin that would be found on a dead animal: amazingly, the tracks were made when the animal was still moving, making the discovery and preservation even more astounding. 

How Were These Preserved Dinosaur Tracks Made?

Way back when the Minisauripus was roaming the earth (about 100 million years ago), there were occasional muddy days just like we have now. At some point on one of those days, the Minisauripus walked over a fine surface of thin mud and left footprints on the sticky top layer. Just like what happens when a person places their fingertips on wet cement and leaves a minuscule layer of skin cells and a fingerprint, the Minisauripus left perfectly preserved footprints in the mud.

Through careful analysis, researchers determined that the dino stepped through the mud mere moments after a gentle rain: they also found preserved raindrops in the fragment of fossilized mud. This slab of printed mud was later covered in more mud, allowing the footprints to be found in their fossilized form today. Significantly less than 1% of preserved dinosaur traces include any amount of skin. It’s rare to even find a trace of tissue or muscle of a dinosaur.  It’s incredible that these tracks were found at all: the footprints of the Minisauripus are only an inch long.

What Was Dinosaur Skin Like?

The preserved dinosaur skin of the Minisauripus is about the texture of medium-grade sandpaper. The patterns on the skin traces and the texture of the skin are very similar to previously discovered examples of mummified bird skin, continuing the bird-dinosaur connection, but the footprints of preserved bird vs. preserved dinosaur are much different. The Miinisauripus footprints are more like their bigger meat-eating dinosaur cousins than they are like the bird prints, and their skin appears to be a much smaller version of the larger dinosaur’s skin.

Have Other Animals Been Preserved This Way?

There are incredibly few examples of preserved dinosaurs or other prehistoric animals that have been found with skin, tissue, or muscle still intact. Paleontologists in Germany found a prehistoric ichthyosaur fossil that contained skin cells and traces of blubber, revolutionizing current theories about the evolution and development of the animals. There have also been mummified Ice Age wolves found in the Yukon with skin and fur — the only one in the world to have ever been found in such a perfect state of preservation. So although there are a handful of other exceptionally preserved animals featuring skin and other cells, this preserved dinosaur discovery is quite rare.

What Does This Mean For Science?

First off, this discovery is interesting and amazing in its own right: the fact that skin and detailed traces of animals can be preserved, discovered, and investigated millions of years after the death of the animal itself is incredible. But for researchers, there’s more to the discovery. Martin Lockley, the co-author of the study which published the dinosaur track findings, says that the information contained in this dinosaur skin will not only help him and his colleagues understand the preserved dinosaur itself but its modern-day descendants.