A Sauropod Footprint with a Skin Impression

This week, a new [paper] was published that described the largest sauropod footprint ever found from the Early Cretaceous (146-100 millions of years ago) of Korea. The footprint is more than 50cm (20 inches) in diameter!

The authors found something very rare inside the footprint: a dinosaur skin impression. That’s the equivalent of leaving a palm print on wet cement, like on the Hollywood Walk of Fame.

Mickey Mouse’s hand and footprints on the Hollywood Walk of Fame. From Pinterest.

The impression preserves interlocked hexagons that have a range of sizes. They seem to get smaller on the outsides of the impression.

Figure 2A from the paper showing the footprint on the left and a close up of the skin impression on the right.

The authors analyzed the sediment around the footprint to try and understand why skin impressions are so rare. They found that these impressions were left in on a muddy surface that had dried enough to preserve the impression. That muddy surface had to stay dry afterwards, and not get covered over by water. If more flooding had occurred, the print would have disappeared. The muddy surface also had to be covered by a thin layer of bacteria in order to hold the mud together. The combination of these conditions allowed the footprint and skin impression to stay preserved. These conditions can be hard to find in the same place and time, meaning that more dinosaur skin impressions could still be rare in the future.