Fossils discovered in Morocco, dating back roughly 773,000 years, provide crucial new evidence about the lineage leading to modern humans, Neanderthals, and Denisovans. The findings suggest that a close ancestor to these groups lived in North Africa before the evolutionary split occurred – a period previously shrouded in mystery. This discovery doesn’t necessarily pinpoint the last common ancestor, but it places us significantly closer to understanding when and where this divergence took place.
Filling a Critical Gap in the Human Story
For decades, scientists have estimated the last common ancestor lived between 765,000 and 550,000 years ago. However, the fossil record from that era, especially in Africa, has been fragmented. The newly analyzed fossils – including adult and child jawbones and vertebrae from the Grotte à Hominidés near Casablanca – fill a “major gap” in this record. The fossils exhibit a blend of primitive and advanced traits: molar teeth similar to Homo sapiens and Neanderthals, yet jaw structures resembling older African Homo erectus species.
A Mosaic of Traits and Potential Connections
The Moroccan fossils existed around the same time as Homo antecessor, a hominin population in Spain previously considered a possible common ancestor. Both groups share a mix of archaic and modern characteristics, implying potential connections across the Strait of Gibraltar. However, the Spanish fossils lean more towards Neanderthal traits, suggesting multiple diverging populations rather than a single, unified ancestor.
“The last common ancestor was likely present on both sides of the Mediterranean at that time and was already diverging,” explains Jean-Jacques Hublin of the Max Planck Institute. This reinforces the idea that modern humans have deep African roots, countering theories proposing an Eurasian origin.
Implications for Human Evolution
The discovery adds weight to paleogenetic studies indicating that Neandertals and Denisovans branched off the human lineage between 1 million and 600,000 years ago. Neanderthals eventually dominated Europe, Denisovans spread into Asia, and Homo sapiens continued evolving in Africa. Some researchers suggest the common ancestor may have existed even earlier – over 1 million years ago – and that migration into Africa later continued the evolution of Homo sapiens.
The Moroccan fossils may even represent an early Homo sapiens ancestor, though further analysis is needed to confirm species assignment. The fossils challenge previously held assumptions about the precise timing and location of key evolutionary events.
The findings underscore the complexity of human origins and emphasize that the story of our species is still unfolding, piece by piece, through fossil discoveries and genetic research.
