Researchers have identified hominin fossils from a cave site in Morocco that are approximately 773,000 years old, potentially filling a crucial gap in the fossil record and reshaping understanding of early human evolution.
The discovery, announced on Wednesday and detailed in a study published in Nature, includes bones and teeth recovered from Grotte à Hominidés, a cave in Casablanca that may once have served as a den for prehistoric carnivores. The remains belong to hominins—upright-walking primates on the evolutionary line leading to modern humans.
The site offers a glimpse into a prehistoric coastal environment where the Atlantic met sand dunes, karst formations and marine terraces. At the time, the region supported rich wetlands and swamps teeming with wildlife, including panthers, hippos, crocodiles, hyenas and jackals.
The fossil assemblage includes a nearly complete adult jawbone, part of another adult jaw, a child’s jaw, several vertebrae and isolated teeth. These remains differ from those found at the nearby Jebel Irhoud site, which at about 300,000 years old represents the earliest known evidence of Homo sapiens.
The Moroccan fossils are particularly significant because they come from a poorly documented period in Africa’s fossil record—between 600,000 and 1 million years ago. This interval is believed to mark the divergence between the African lineage that led to Homo sapiens and Eurasian hominins that later gave rise to Neanderthals and Denisovans.
Researchers found that the Grotte à Hominidés remains closely resemble Homo antecessor, a species identified in the 1990s at Gran Dolina in Spain and dated to a similar period. Those Spanish fossils, which displayed a mix of primitive and modern features, pushed back the known presence of humans in Western Europe by hundreds of thousands of years.
The Gran Dolina discoveries challenged the idea that modern humans evolved exclusively in Africa before replacing other hominins elsewhere. Instead, they suggested early hominins left Africa earlier and evolved into distinct populations across Europe and Asia, with Homo antecessor proposed as a possible link between African ancestors and later European hominins.
Although distinct from the Spanish fossils, the Moroccan remains also show a mosaic of traits. According to Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology, the lead author of the study, this pattern suggests that the last common ancestor of Homo sapiens, Neanderthals and Denisovans existed on both sides of the Mediterranean and that the split between African and Eurasian lineages was already underway at the time.
Scott A. Williams, a paleoanthropologist at New York University who was not involved in the research, said the findings indicate movement between northern Africa and southern Europe throughout the Middle Pleistocene epoch, which lasted from about 774,000 to 129,000 years ago—and possibly earlier.
Determining the age of the fossils proved challenging at first, as early estimates conflicted with surrounding geological evidence. However, the site’s sediments preserved clear records of past reversals in Earth’s magnetic field. Using high-resolution magnetostratigraphy, researchers matched the fossil-bearing layer to the most recent major magnetic reversal, producing one of the most precise age estimates for African hominin fossils from the Pleistocene.
Whether the Moroccan remains represent the last common ancestor of modern humans, Neanderthals and Denisovans remains uncertain. Scientists estimate that this ancestor lived between about 550,000 and 765,000 years ago, but limited fossil evidence continues to fuel debate. Candidates include Homo antecessor, Homo heidelbergensis, or a yet-unknown hominin.
Much about this ancestor remains unclear, including its physical appearance, how its populations evolved over time, and when and where key divergences occurred. Despite advances in DNA analysis revealing a complex evolutionary history, the fossil record may still be missing critical pieces of the story.
