A 7.2-million-year-old femur discovered in Bulgaria is prompting scientists to reconsider long-held beliefs about the origins of humankind. The find challenges the widely accepted theory that the first human ancestors emerged in Africa, suggesting a possible origin point in Europe.
Details of the discovery, published in the journal Palaeodiversity and Palaeoenvironments, reveal the fossil was unearthed at the Azmaka archaeological site, near the town of Chirpan in Bulgaria’s Upper Thracian Plain. Researchers believe the bone dates back 7.2 million years and exhibits characteristics associated with early hominids.
The fossil belongs to an individual of the genus Graecopithecus sp., a prehistoric primate whose classification as a human ancestor has been debated since 2017, when fragments of jaw and teeth from the group were found in Greece. This new fossil provides crucial evidence regarding the animal’s locomotion.
According to scientists, the femur possesses anatomical features consistent with bipedal locomotion – walking upright on two legs. A longer, upward-pointing femoral neck, specific muscle insertion points, and a particular thickness of the outer bone layer all support the conclusion that the individual was bipedal, mirroring characteristics found in modern human ancestors.
Nikolai Spassov, a researcher at the National Museum of Natural History of Bulgaria and co-author of the article, said in a statement that “the external and internal morphology of the femur presents similarities with fossils of bipedal human ancestors.”
Researchers estimate the bone belonged to a female weighing approximately 24 kilograms (53 pounds) who lived near a river in a savanna-like environment. The femur exhibits a combination of traits typical of large apes and later bipeds, suggesting an intermediate form of locomotion and a transitional stage in the development of upright walking.
A Shift in History
Currently, the title of oldest known hominid belongs to the genus Orrorin sp., discovered in Kenya and dated to approximately 7 million years ago. If Graecopithecus sp. Is confirmed as a member of the human lineage, it would predate Orrorin sp. And shift the origin of hominids to Eurasia.
Researchers suggest that Graecopithecus sp. Likely descended from primates that lived in the Balkans and Anatolia between 8 and 9 million years ago. Climate changes occurring between 8 and 6 million years ago may have played a fundamental role in the evolutionary process.
The reduction of forests would have pressured various primates to adapt to more open environments, favoring terrestrial locomotion and the emergence of bipeds. These environmental changes also likely triggered migrations of Eurasian mammals to Africa, a process that helped shape the fauna of African savannas today, as reported by the magazine Galileu.
Paleontologist Madelaine Bohme suggests that great apes may have followed a similar path, migrating from Eurasia to the African continent, where later forms of the human lineage would emerge.
If the interpretation is correct, the earliest representatives of the human lineage would have originated in Eurasia before establishing themselves in Africa, where subsequent hominid genera evolved. The discovery could reshape our understanding of the complex journey of human evolution.
Despite the excitement surrounding the discovery, researchers emphasized that the hypothesis still needs further testing.
*Under the supervision of Éric Moreira
