Several footprints and exquisitely-preserved skin impressions made by a small theropod dinosaur approximately 120 million years ago (Aptian age of the Early Cretaceous epoch) have been found in the Jinju City area in Korea.
The Jinju footprints, assigned to the ichnogenus Minisauripus, are only an inch long (2.5 cm), and paleontologists were able to find perfectly preserved skin traces on them.
“These are the first tracks ever found where perfect skin impressions cover the entire surface of every track,” said University of Colorado Denver’s Professor Martin Lockley.
“They were made on a very thin layer of fine mud, rather like a coat of fresh paint only a millimeter thick.”
“When the tiny dinosaur stepped on this firm, sticky surface, the skin texture of the foot was reproduced perfectly, without slipping or sliding.”
Evidence shows that, just before the tracks were made, there had been a rain shower leaving water-drop impressions.
In one place, the dinosaur had stepped on a fresh rain drop mark, proving rain came first, and the dinosaur step came second.
All this delicate evidence was preserved by being gently covered with more fine mud.
“The skin pattern as similar to examples from much larger, carnivorous theropod dinosaur tracks, in which scales are much larger but never preserved across the whole footprint,” Professor Lockley and colleagues said.
“The more distantly-related giant brontosaurs had scales that left traces 0.8-1.2 inches (2-3 cm) in diameter.”
“So the delicate, perfectly-preserved Minisauripus skin texture is like a shrunken version of the skin of a much larger relative, with no shrinkage of the skin traces.”
The research was published in the journal Scientific Reports.
Kyung Soo Kim et al. 2019. Exquisitely-preserved, high-definition skin traces in diminutive theropod tracks from the Cretaceous of Korea. Scientific Reports 9, article number: 2039; doi: 10.1038/s41598-019-38633-4