In a complete redefinition of the term ‘cute’, an international team of paleontologists has identified the smallest known stegosaurus footprint.
The imprint has been preserved in the stone in China’s Xinjiang province for 100 million years and is only 5.7 centimeters long and was probably made by a baby stegosaurus (ichnogenus). Delta Pod) about the size of a cat, the research team said.
Fascinatingly, although we do not know the exact species of the small animal, scientists have allowed the imprint to infer that infant stegosaurs walked differently than adults.
“This footprint was made by a herbivorous, armored dinosaur widely known as a 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 adult nails on its tail and bony plates along its back. With a footprint of less than six centimeters, it is the smallest stegosaurus footprint in the world.”
The stegosaurus footprint. (Xing et al., Palaios, 2021)
We know that stegosaurs lived in the region. Dozens of traces up to 30 centimeters long were found, as well as skeletal remains. Elsewhere in the world, stegosaurus spores rarely exceed 50 centimeters.
The footprints of many young stegosaurs and other armored dinosaurs are incredibly rare compared to other species, and it is not entirely clear why.
It is possible that many of their prints, living in a herd, were overrun by larger, heavier adults, but this does not entirely explain how the baby prints of other herd dinosaurs survived. Other explanations include rapid growth – the animals may not have been small enough long enough to leave many traces; or that nursery habitats were generally not conducive to maintaining footprints.
Whatever the reason for the scarcity, this one single track somehow survived. The baby’s three-footed foot presses into the mud; time turned the mud into mudstone, creating a mold filled with debris that eventually turned into sandstone, creating a casting of the small staircase that survived when the mudstone eroded.
Although not much detail was preserved, the shape of the print was intriguing – it was not as elongated as the traces of older stegosaurs, the researchers said.
The prints of older stegosaurs found at the site. (Xing et al., Palaios, 2021)
“Stegosaurs usually walked with their heels on the ground, just like humans, but on four feet that create long footprints,” Romilio said.
“The small orbit shows that this dinosaur pulled up from the ground with its heel, just as a bird or cat does today. We have only seen shortened tracks before when dinosaurs walked on two legs.”
This tantalizing finding suggests that baby stegosaurs could have moved lighter and smoother than the adults, walked on their toes, and switched to heel walking as they grew. With only a single footprint, however, it is impossible to see.
The specific individual stegosaurus that made it could have had a strange way of walking; or maybe it put his foot down strangely, just for one step.
“A complete set of footprints from these small footprints will give us the answer to this question,” said Lida Xing, paleontologist at the China University of Geosciences, who found the pressure, “but unfortunately we only have one footprint.”
The region in which the print was found yielded nine different sites for dinosaurs; and the specific composition that included the baby print also had 16 other prints of older stegosaurs. Now that one baby print has been found, the team plans to search the formation for clues that can help us answer these fascinating questions.
The research was published in Palaios.