Smallest Footprint of Stegosaur Found

Stegosaur – Tiniest Footprint

An international team of palaeontologists has discovered the tiniest known stegosaur footprint, completely redefining the term “cute.”

The print, which has been preserved in stone for 100 million years in China’s Xinjiang Province, measures only 5.7 centimetres (2.24 inches) long and was most likely created by a baby stegosaur (ichnogenus Deltapodus) around the size of a cat, according to the research team.

Interestingly, despite not knowing the exact species of the wee little beast, scientists have deduced that baby stegosaurs might have walked differently than adults based on the print.

Researchers Say

“This footprint was left by a herbivorous, armoured dinosaur known as a stegosaur – the dinosaur family that includes the famous stegosaurus,” said paleontologist Anthony Romilio of the University of Queensland in Australia.

“As an adult, this small dinosaur had spikes on its tail and bony plates along its back, similar to the stegosaurus. This is the world’s smallest stegosaur footprint, measuring less than six centimetres in length.”

Stegosaurs were known to have lived in the region. Hundreds of tracks, some up to 30 centimetres long, as well as skeletal remains, have been discovered. Stegosaur tracks rarely reach 50 centimetres elsewhere in the world.

Footprints Extremely Rare

The footprints of very young stegosaurs and other armoured dinosaurs are extremely rare compared to those of other animals, and the reason for this is unknown.

It’s likely that because they lived in a herd, many of their prints were trampled by bigger, heavier adults, but that doesn’t explain how the baby prints of other herd dinosaurs survived. Other possibilities involve rapid development, in which case the animals might not have been small enough to leave many traces, or that the nursery environments were not conducive to the preservation of footprints in general.

Whatever the cause of scarcity, this one single track managed to thrive. The baby’s three-toed foot pressed into the mud; time turned the mud to mudstone, forming a mould that filled with debris, then weathered away, leaving a cast of the tiny step.

Intriguing Print Shape

The shape of the print was intriguing, the researchers said, despite the lack of detail. It wasn’t elongated like the tracks of older stegosaurs.

“Stegosaurs walked on all fours, similar to humans, but with their feet on the ground, leaving long footprints,” Romilio explained.

“This dinosaur was moving with its heel raised off the ground, just like a bird or cat does today, according to the tiny track. Only when dinosaurs walked on two legs have we seen shortened tracks like this.” 

This intriguing find indicates that baby stegosaurs may have walked more gently and nimbly than adults, walking on their toes at first and then changing to heel walking as they grew older. With just one footprint, though, it’s hard to tell.

It’s possible that the individual stegosaur who created it walked in an unusual manner, or that it put its foot down in an unusual manner only for that one move.

Issue to be Answered

“A full collection of tracks of these tiny footprints will provide us with the answer to this issue,” said Lida Xing of the China University of Geosciences, who discovered the print. “Unfortunately, we only have a single footprint.”

Nine different dinosaur track sites have been discovered in the area where the print was discovered, and the assemblage that included the baby print also included 16 other prints from older stegosaurs. The team plans to search the formation for clues that can help us answer these fascinating questions now that one baby print has been discovered.

The findings were published in Palaios.