An 80-million-year-old dinosaur footprint, measuring 1.2 meters (4 feet) across, has been found in Bolivia.
It is easily one of the largest ever found, and likely belonged to an Abelisaurus, a bipedal, powerful predatory carnivore that once stalked the plains of South America long before the famous T. rex entered the fray. Based on this print, the monstrous sharp-toothed hunter would have been 15 meters (49 feet) long.
“This print is bigger than any other we have found to date in the area,” Sebastian Apesteguia, a paleontologist from the Argentinian-based National University of La Plata, told Reuters. “It is a record in size for carnivorous dinosaurs from the end of the Cretaceous period in South America.”
The giant clay mold was found by a tourist guide 64 kilometers (40 miles) from the central Bolivian city of Sucre. The ancient clay in this region is inherently soft, and the area is famous for preserved dinosaur tracks as a result.
There is much about Abelisaurus that remains unknown to researchers. Most of what they do know is based on a single fossil, one that consists of a partially-preserved fossilized skull unearthed in Argentina in 1983. Based on this, the type specimen Abelisaurus comahuensis was roughly 9 meters (30 feet) in length, but this is difficult to ascertain from just its head size.
This new footprint gives researchers a rough idea of how truly massive this variety of beast was, based on reasonable and well-established connections between dinosaurian foot size and height. These dinosaurs were likely all feathered, and just like the fearsome T. rex that appeared 13 million years later, they were the apex predators of their environment.
The restored skull of the single recovered Abelisaurus fossil. Kokoo/Wikimedia Commons; CC BY-SA 2.5
Although they bit the dust 66 million years ago, the non-avian dinosaurs left behind plenty of bones for paleontologists to comb over. Thanks to these fossils, we know that giant beasts ruled the world for 186 million years, ranging from the utterly weird Murusraptor to the adorable Chasmosaurus.
However, it’s not just bones they left behind. Fossilized footprints, a type of “trace fossil,” are becoming increasingly important in the field of paleontology. Footprints reveal so much that bones simply don’t – how dinosaurs walked or ran, and at what speed, and whether or not they travelled alone or in groups. The also constrain overall size estimates when bone-based evidence is scarce.
One recent study interpreted a series of closely-spaced groups of footprints made by several T. rex to suggest that they hunted in packs, and weren’t always solitary predators. Another paper showcased the discovery of the track marks of an adolescent T. rex to reveal it was moving at a slow pace of 8 kilometers per hour (5 miles per hour).
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