Researchers carefully examined some fossilized bird tracks in Africa that are approximately 210 million years old. These traces are almost a mystery: Even fossils of the first ancestors of birds were not found for 60 million years.

These traces have been known for years, but a team from the University of Cape Town in South Africa wanted to do a more comprehensive analysis of fossils actually taken from four different sites in the region.

Specifically, by examining records found in the Mafutseng area, an 80-foot (262-meter) section of track, researchers were able to identify two distinct track species (or morphotypes) within the previously known category of Trisauropodiscus. assigned to the three-fingered tracks of these birds.

“Our results show that Trisauropodiscus has two distinct morphotypes, one of which resembles the tracks left by birds,” geologists Mienga Abrahams and Emese Bordi write in their paper.

According to the researchers, the feet of the first morphotype were larger and longer, and their toes were closer together. These tracks are not that different from another type of fossilized tracks, Anomoepus, which researchers believe remains a type of dinosaur.

As for the second type, these footprints were half as short as average, wider than long, and had thin toes. This morphotype is more mysterious but closer to modern birds.

Researchers believe that the tracks that fall into the second morphotype category were left by the first ancestors of birds. So dinosaurs may have begun to exhibit some bird characteristics much earlier than the fossil record indicates.

“The fact that these Late Triassic southern African tracks are so similar to Cenozoic and modern bird tracks supports the convergent pedal morphology of Late Mesozoic archosaurs and strongly suggests that the origin of bird foot morphology was at least ~2 years old,” the researchers write.

The mystery of which ancient beast actually left these tracks remains to be solved, but researchers believe it was a type of three-toed archosaur, a branch of the evolutionary tree that gave us both birds and crocodiles today. While the hunt for fossils that could tell us more about the animal responsible for these tracks continues, the study offers a fascinating look back hundreds of millions of years ago and how birds have evolved since then.

“Fossil traces can be used to make inferences about ancient diversity, ethology, and evolutionary trends,” Abrahams and Bordi write. “This is particularly useful for deep time intervals where the early history of an animal group depends on limited fossil skeletal material.” Source