Two years ago, Emese M. Bordy, a sedimentologist at the University of Cape Town, was flipping through an obscure dissertation from the 1960s when a clue leapt out at her. It was an image of a footprint on a farm located on the northern Karoo Basin of South Africa.

The Karoo region contains huge volcanic flood basalts that chronicle the final epoch of the ancient supercontinent Gondwana before it broke apart about 180 million years ago during a period of tectonic and volcanic catastrophe. Geologists have been studying it for decades to understand this major change in the layout of Earth’s landmasses, which coincided with a mass extinction event.

But the image suggested to Dr. Bordy that there was more to learn about the prehistoric animals that had lived on that dying supercontinent. That initial hunch sparked something like a paleontological detective tale.

First, Dr. Bordy and her colleagues were able to track down the farm’s owner with the help of a local historian. He gave her team permission to hunt for fossils on his property. There, the team not only found the pictured footprint, but also discovered two dozen other prints left 183 million years ago by carnivorous and herbivorous dinosaurs, as well as small creatures called synapsids.