Jan Bartek – AncientPages.com – A team of scientists has reported an extraordinary discovery deep within an old excavation site, one that may reshape our understanding of human evolution. Their work invites us to appreciate the possibility that our past is far more complex, interconnected, and astonishing than anything we learned from textbooks.

This finding could transform how we view our ancestors, our past, and ourselves. At the heart of this discovery is a subtle yet vital detail that the researchers highlight as absolutely crucial.

For years, it has been widely accepted that the earliest species on the human evolutionary branch emerged in Africa around seven million years ago. Now, a remarkable find in Europe encourages us to look at this history with fresh eyes.

In their new study, scientists ask: What if the oldest human ancestor can be traced to an entirely different place?

An international team of researchers has made a remarkable discovery: a fossil thighbone from Bulgaria that may transform our understanding of human origins. Found at the Azmaka excavation site near the town of Chirpan in the Upper Thracian Plain, this fossil offers an exciting new perspective on where and when our human story began.

Has The History Of Bipedalism Been Rewritten?

Walking on two legs has long been recognized as a defining milestone in human evolution. For years, scientists believed that the first humans originated in Africa and that bipedalism developed there around six million years ago.

Now, thanks to the dedicated work of experts from Bulgaria’s National Museum of Natural History, Aristotle University of Thessaloniki in Greece, the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen in Germany, and the University of Toronto in Canada, we have compelling evidence that challenges this timeline. Their analysis of the femur reveals clear features of a biped—a human ancestor walking upright more than seven million years ago, earlier than previously thought.

To fully appreciate this discovery, it helps to understand the term “hominins,” which refers to all species along the human evolutionary line—both modern humans (Homo sapiens) and our prehistoric relatives. Until now, the species Orrorin, which appeared in Kenya around seven million years ago, has been regarded as the oldest known hominin. Its ability to walk on two legs distinguished it from the chimpanzees from which we are descended.

What makes this new finding so interesting is that it points to the possibility of an even older species in the Balkans being the first two-legged creature—and thus the first hominin. This species, a primate called Graecopithecus, was initially identified from teeth discovered in Greece in 2017. The first known Graecopithecus fossil—a fragment of a lower jaw—was discovered at a site near Athens.

Researchers analyzed this specimen and determined that the shape of its tooth roots indicated Graecopithecus may have been an early human ancestor. While the jawbone did not reveal how the animal moved, the newly discovered femur from the Azmaka site in Bulgaria now offers important additional evidence about its locomotion and adds meaningful weight to the idea that our earliest upright-walking ancestors may have lived in this region.

Is Graecopithecus The Earliest Human Ancestor?

“At 7.2 million years old, this ancestor, which we classify as belonging to the genus Graecopithecus, could be the oldest known human,” says Professor David Begun of the University of Toronto.

The thighbone discovered in Bulgaria likely belonged to a female who weighed around 24 kilograms. Evidence suggests she lived near a river in a savanna-like environment, resembling the landscapes found in present-day East Africa.

The Graecopithecus femur from Azmaka, Bulgaria, (left) in comparison with that of Lucy (Australopithecus afarensis) (middle) and the thighbone of a chimpanzee (right). The femoral neck (indicated in red) is longer and more upward-pointing in the human ancestors Graecopithecus and Australopithecus than in the chimpanzee. Credit: N. Spassov, D. Youlatos, M. Böhme, R. Bogdanova, L. Hristova, D. Begun

“A number of external and internal morphological features, such as the elongated, upward-pointing neck between the femur shaft and head, special attachment points for the gluteal muscles, and the thickness of the outer bone layer, have similarities with bipedal fossil human ancestors and humans,” says Professor Nikolai Spassov of the Bulgarian National Museum of Natural History.

This is where they differed from the thighs of tree-dwelling apes. “However, Graecopithecus did not quite move the way modern humans do,” Spassov adds. The Azmaka thigh combines features of African apes with those of more recent bipeds.

Researchers explain that Graecopithecus represents a stage in human evolution between our arboreal ancestors, such as the nearly twelve-million-year-old Danuvius guggenmosi from southern Germany, and more recent finds from East Africa. One could describe it as a missing link. Graecopithecus most likely descended from eight- to nine-million-year-old Balkan-Anatolian apes like Ouranopithecus and Anadoluvius, which themselves evolved from ancestors in western and central Europe.

It is also important to recognize that climate change played a key role in driving dispersal, influencing how and where species, populations, or human groups moved over time.

“We know that large-scale climate changes in the eastern Mediterranean and western Asia led to the periodic emergence of extensive semi-deserts and deserts eight to six million years ago. This set off several waves of dispersal of Eurasian mammals to Africa and laid the foundation for today’s mammal fauna of African savannas,” says Professor Madelaine Böhme from the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen.

Researchers, therefore, suspect that great apes also expanded their range southward. It remains uncertain whether the ancestors of chimpanzees, gorillas, and humans had already diverged while in Europe, and whether these successive dispersal events contributed to the genetic separation of their lineages.

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One possibility is that Graecopithecus spread from the Balkans into Africa, where, from about six million years ago, early human ancestors such as the genus Orrorin appeared, followed later by Australopithecus afarensis—best known from the famous fossil specimen “Lucy.”

Ongoing excavations at Azmaka and other Balkan sites aim to uncover additional Graecopithecus fossils and to clarify the environment, behavior, and evolutionary significance of this unexpectedly early biped and potential human ancestor.

The study was published in the journal Palaeobiodiversity and Palaeoenvironments

Written by Jan Bartek – AncientPages.com Staff Writer