Ten thousand years or more ago, people began painting the walls of caves near Bhopal, India. Over the millennia, they made thousands of images in what is now the Bhimbetka Rock Shelters: men, women, a couple having sex, dancers, children, hunts, battles, around 29 different species of animals and mythical beasts like a partial pig. Ox part elephant.

Over time the art styles changed. Human figures attracted each other. Horses and elephants sprout riders. Wars danced over sandstone walls. Today, many of the cave walls are palimpsests. Medieval warriors cover Chalcolithic art on even older Mesolithic drawings.

Still, an overlooked pattern that a tour group of scientists discovered in March 2020 seemed so, so, so much older. Older than representational art or humans or primates or fish or horseshoe crabs. Eleven feet up the wall of an area called Auditorium Cave, visitors had identified what looked a lot like an imprint of Dickinsonia, a legendary 550 million year old fossil from the first bloom of complex life on Earth.

The group of geologists traveled to India for the International Geological Congress last spring, which was then canceled due to the pandemic. However, pre-conference excursions continued, including a visit to the caves led by Ranjit Khangar and Merajuddin Khan of the Geological Survey of India.

“Talk about serendipity,” said Gregory Retallack, a paleontologist at the University of Oregon who described the 17-inch fossil in the journal Gondwana Research earlier this month. “Can you find it where we wouldn’t expect a cultural stop on the last day of the expedition?”

Dr. Retallack and the others had no hammers or equipment. Instead, they took as many different pictures from as many different angles as possible. After the trip home, they used image-based 3D modeling software to take a closer look.

Dickinsonia, a lump with internal ridges that vaguely looks like a Christmas ham cut in half, was found in Australia, Russia, Ukraine, and from January near China’s Three Gorges Dam. No Indian specimens were known. But the size, shape, and surrounding rocks of the Bhimbetka pattern are all consistent with Dickinsonia fossils elsewhere, the team argues, confirming the find.

Within Indian geology, the discovery could settle a long debate about the age of ancient basins such as that in which the Bhimbetka site is located. Some studies date these rocks to 800 or 900 million years ago; others have suggested they are younger. Fossils tied to specific age groups, like footnotes on the pages of a book, could help.

“People have tried for decades to study the fossil content of these rocks and they haven’t found much convincing evidence,” said Suvrat Kher, a science journalist in Pune, India. However, the presence of Dickinsonia results in an age of around 550 million years.

Other scientists note that Dr. Retallack is embroiled in a deep debate about where Dickinsonia and other bizarre early organisms fit on the tree of life.

The recent scientific consensus has shifted to referring to them as prototypical animals that lived on the ocean floor. But Dr. Retallack’s work found that these organisms, including this one, lived on land, not in the sea, and that they were lichens.

But its critics make an exception to this statement.

“Most of Greg’s work has a million reasons it’s wrong,” said Emily Mitchell, a paleontologist at Cambridge University. “For me it is doable. And if it did, it would be very, very cool. “

The discovery could really be Dickinsonia, she said. One way to look into this further might be to get permission to scrape off a little bit of material and test it. But considering where it was found, it could also be a painting or a petroglyph, a possibility that is found in Dr. Retallack’s study was rejected.

If it’s just cave art, it might just be a satisfying, simple design that looks just like Dickinsonia to paleontologists who already have this fossil in mind. Or to create confusion, it could even be an old representation of a Dickinsonia.

Maybe it’s a drawing that happens to look like a fossil, or a drawing about a fossil, or maybe it’s the real thing: a trace from the beginning of life almost overwritten by the beginning of human creativity.

In this latter case, “I think wow you can’t have missed it,” said Dr. Retallack and speculated about the cave artists. “I wonder if that’s why you decided to decorate the cave?”