The paper was trapped under a rock for thousands of years. Could it, then, be the fossilized remains of a prehistoric marsupial bear once described as the largest and most powerful animal on Earth? Yes — and that’s even more remarkable since the print comes from Tunisia.
Researchers studying the rock found an incandescent red-and-white print last August in an ancient geological formation at Anja, Tunisia, that some observers thought could be the first fossilized inkmark of any mammal. The print, like a well-placed selfie, was preserved in a rock formation about 20 to 30 feet underground.
At that time, however, a debate was raging over whether the print was a bear print. One group of scholars hailed it as a “first-of-its-kind inkmark.” This group included the North Carolina Museum of Natural Sciences in Durham, where I was examining prints left behind by the carnivorous shrew-like beasts, living about 15 million years ago. Other groups questioned its authenticity, but other researchers — who included researchers at Tunisian universities — thought it was the real deal.
Last week, the Tunisian scientists published a report in the Journal of Geographical Science concluding that the print was indeed a print left by a bipedal marsupial bear. They surmised that the print was created by a mastodon-like bear that lived around 15 million years ago, weighing around 400 pounds, standing approximately 12 feet tall, and adding another 25 feet to its eight-foot-long arm span. They found the print in what is now a mudstone slough. So how did it get stuck in there?
While millions of years of erosion dissolved one section of a river valley, they noticed that a portion of the actual river bed remained submerged in mudstone. The team reached into the mudstone and “pulled out” the imprint — even uncovered a footstep below it. They calculated the print was about 12,000 years old, which makes it more than likely that it was left by a copy of the larger marsupial bear that’s known to have existed in the region during that period.
In addition to the print, the team uncovered teeth fragments, an australopithecine embryo and other animal bones in a sedimentary layer that the scientists say was likely deposited from the river.
So how did the print come to be in such a context? Some researchers, including those who were first to believe that the print was that of a mastodon, suggested that the print was probably the result of some way of cleansing the sediment with charcoal to allow liquid to flow in without compromising its quality. But the Tunisian researchers apparently reached the opposite conclusion, surmising that no hard charcoal was present in the areas where the print was found. It was more likely that the print was left by animal poop.
Whatever its origin, the prints likely prove that prints made by modern species of mammals, or even from the collective brain of modern animals, could remain embedded in solid rock for thousands of years, if not millions.
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