Gobi Desert dinosaur footprint: What does it mean?

Could massive fossilized footprints help settle Titanosaurs' contentious classification?

These colossal feet were definitely made for walking. But what did that walk look like?

That’s what paleontologists from Japan’s Okayama University of Science hope to determine from a newly uncovered Titanosaur footprint, discovered last month in Mongolia’s Gobi Desert. The print, which was announced Friday, is among the largest ever found.

“This is a very rare discovery as it's a well-preserved fossil footprint that is more than a metre long with imprints of its claws,” researchers said in a statement issued by Okayama University of Science in Japan, according to the International Business Times. 

The footprint was created between 70 and 90 million years ago, when a dinosaur pressed its massive foot into a patch of mud. Loose sand flowed into the cast, and millions of years of geologic activity compressed and fossilized it. Given the print’s size and shape, researchers say it was likely made by a Titanosaur.

Titanosaurs, so-named for their impressive size, were a group of long-necked dinosaurs that lived during the middle-Cretaceous period. One yet-unnamed specimen, which debuted at New York’s American Museum of Natural History earlier this year, spans a whopping 122 feet from head to tail. But aside from size, little else is known about these humongous herbivorous.

With precious few fossils to work from, some critics have considered Titanosaurus to be a kind of “wastebin taxon” – a default classification for poorly-preserved long-necked herbivores. About 60 have been formally named, and only a small percentage of those have semi-complete fossil records.

That’s why a well-preserved footprint is so useful to paleontologists. Such a print, if it does indeed belong to a Titanosaur, could yield new insight about the dinosaur’s locomotion and physiology. And that information could lead to more accurate classification.

Earlier this year, the partial skull of Sarmientosaurus musacchioi, a species of Titanosaur native to Patagonia, provided new revelations about the so-called “titanic lizards.” Based on a tiny brain casing and large eye sockets, researchers from Universidad Nacional de la Patagonia San Juan Bosco determined that the creature probably had strong vision despite its low intelligence. Long hearing ducts suggest that Sarmientosaurus probably relied on its ability to hear noises from far away.

The Christian Science Monitor’s Ben Thompson reported:

The positioning of its inner ear also suggests that the Sarmientosaurus probably planted its tree-trunk legs and faced downward to feed... It also has a unique tooth orientation distinct from other sauropods, although the scientists were unable to ascertain for certain what that would have meant for the dinosaur’s eating process or diet.