100 million years in the past, a wee child stegosaur pranced round on its hind ft in what’s right now China.
The footprint of this cute, cat-size tot from the Cretaceous interval was found in Xinjiang, a territory in northwest China. At solely 2.25 inches (5.7 centimeters) lengthy, it is the smallest stegosaur print ever discovered, the authors reported March 3 within the journal Palaios.
The positioning the place the tiny prints had been discovered was additionally pock-marked with massive footprints from stegosaurs — a gaggle of herbivorous dinosaurs that included the genus Stegosaurus — that averaged round 11 inches (29 cm) lengthy on the again foot and about 5.3 inches (12.7 cm) lengthy on the entrance foot. There was one tiny again footprint with the distinctive three-toed form of stegosaurs. It isn’t clear which species the footprint belonged to, however skeletal stays of a species known as Wuerhosaurus homheni have been discovered within the space. This species is understood solely from fragmentary bones, however from these scientists comprehend it sported the enduring again plates that stegosaurs are well-known for.
“Just like the Stegosaurus, this little dinosaur in all probability had spikes on its tail and bony plates alongside its again as an grownup,” research co-author Anthony Ramilio, a researcher within the Dinosaur Lab on the College of Queensland, mentioned in an announcement.
Potential tiny stegosaur footprints have been discovered earlier than, although whether or not they actually belonged to stegosaur infants is controversial. Tiny tracks have been discovered close to Morrison, Colorado, in rocks from the Jurassic interval (199 million to 145 million years in the past), however not all paleontologists agree that these footprints are fossils. One of many co-authors on the brand new paper, paleontologist Marin Lockley, a professor emeritus on the College of Colorado at Denver, argues that these prints are literally simply chunks of irregularly formed mud embedded in sandstone.
Not like the bigger tracks on the Xinjiang web site, the tiny observe was not elongated. This was intriguing to researchers, as a result of it suggests the newborn stegosaur could not have moved like its grownup counterparts.
“Stegosaurs sometimes walked with their heels on the bottom, very like people do, however on all fours which creates lengthy footprints,” Romilio mentioned. “The tiny observe reveals that this dinosaur had been shifting with its heel lifted off the bottom, very like a chicken or cat does right now. We have solely beforehand seen shortened tracks like this when dinosaurs walked on two legs.”
It is attainable that toddler stegosaurs walked on their hind ft, transitioning to 4 ft as they grew bigger, mentioned research co-author Lida Xing, a paleontologist on the Chinese language College of Geosciences in Beijing.
“An entire set of tracks of those tiny footprints would supply us with the reply to this query, however sadly we solely have a single footprint,” Xing mentioned in an announcement.
Initially revealed on Dwell Science.