In a complete redefinition of the concept of “cute”, an international team of paleontologists has identified the smallest known footprint of stegosaurs.
Preserved in stone in China’s Xinjiang province for 100 million years, the print is only 5.7 centimeters (2.24 inches) long and was probably made by a baby stegosaurus (ichnogenus). Deltapod) around the size of a cat, the research team said.
Fascinatingly, although we do not know the exact species of the small animal, the fingerprint allowed scientists to deduce that stegosaurus babies could have behaved differently from adults.
“This imprint was made by an armored herbivorous dinosaur, generally known as the stegosaurus – the family of dinosaurs that includes the famous stegosaurus,” said paleontologist Anthony Romilio of the University of Queensland in Australia.
“Like the stegosaurus, this small dinosaur probably had tail tips and bone plaques along its back as an adult. With a footprint of less than six centimeters, this is the smallest stegosaurus footprint known in the world.”
The stegozaur’s imprint. (Xing et al., Palaios, 2021)
We know that stegosaurs lived in the region. Dozens of tracks up to 30 centimeters long were found, as well as skeletal remains. Elsewhere in the world, traces of stegosaurs rarely exceed 50 centimeters.
The fingerprints of very young stegosaurs and other armored dinosaurs are incredibly rare compared to other species and it is not at all clear why.
It is possible that, living in a herd, many of their fingerprints were crossed by older and heavier adults, but this does not really explain how the baby fingerprints of other herd dinosaurs survived. Other explanations include rapid growth – the animals may not have been small long enough to leave many marks; or that nursery habitats were generally not conducive to keeping footprints.
Whatever the reason for the deficit, somehow this one piece survived. The baby’s three-toed foot pressed into the mud; time turned the mud into mud stone, creating a mold that filled with debris that over time turned into sandstone, creating a distribution of the small step that survived when the mud stone went out.
Although not many details have been preserved, the shape of the print was fascinating – it was not elongated like the traces of older stegosaurs, the researchers said.
Footprints of older stegosaurs found on the site. (Xing et al., Palaios, 2021)
“Stegosaurs usually walked with their heels on the ground, just like humans, but on all fours, which creates long marks,” Romilio said.
“The small route shows that this dinosaur was moving with its heel raised from the ground, just like today a bird or a cat. I’ve seen shortcuts like this before only when dinosaurs walked on two legs. ”
This tempting finding suggests that stegosaurus babies may have moved more easily and skillfully than adults, walking on their toes and moving on their heels as they grew older. However, with a single fingerprint, it is impossible to say.
The individual stegosaurus that made it could have had a strange way of walking; or maybe he put his foot down strangely, just for that step.
“A complete set of clues to these tiny fingerprints would give us the answer to this question,” said paleontologist Lida Xing of China University of Geosciences, who found the fingerprint, “but unfortunately we only have one fingerprint.” .
The region where the print was found produced nine different dinosaur tracking sites; and the specific set that included the baby fingerprint had another 16 fingerprints from older stegosaurs. Now that a copy has been found for the babies, the team intends to look for clues in the formation to help us answer these fascinating questions.
The research was published in Palaios.