773,000-Year-Old Moroccan Fossils Offer New Perspective on Human Deep Origins

Researchers dated hominin remains from Grotte à Hominidés in Casablanca to about 773,000 years ago and report the bones combine Homo erectus-like traits with features seen in Neanderthals and early Homo sapiens, which could place them near the root of the shared ancestry of modern humans and some archaic cousins.

Researchers report analysis of hominin fossils recovered from Grotte à Hominidés at Thomas Quarry I near Casablanca that they dated to about 773,000 years ago using magnetic signals tied to the Matuyama–Brunhes reversal. The assemblage includes a nearly complete adult mandible, a partial adult mandible, a child's mandible, several vertebrae and multiple teeth, and one femur bears gnaw marks consistent with carnivore activity. The remains show a mix of features seen in Homo erectus and traits associated with Neanderthals and modern humans. The team and outside commentators say the fossils could represent populations near the common ancestry of Homo sapiens, Neanderthals and Denisovans and help fill a gap in the African fossil record from this period. Key findings: - Sediment magnetism tied the fossil-bearing layers to the Matuyama–Brunhes magnetic reversal, giving an age of about 773,000 years for the remains. - The recovered material includes multiple lower jaws, teeth and vertebrae, plus a femur with gnaw marks; stone tools were also present at the site. - Morphological analyses, including study of the enamel-dentine junction, indicate the fossils are distinct from both Homo erectus and Homo antecessor and combine more primitive and more modern traits. - Authors report the specimens could be basal to the Homo sapiens lineage and related to the shared ancestry with Neanderthals and Denisovans, reinforcing a deep African origin for those lineages. - Researchers caution the sample is small and fragmentary, and they avoided assigning the remains to a specific species at this stage. Summary: The discovery adds fossil evidence in northwestern Africa for populations that show a blend of archaic and modern traits and helps narrow a previously sparse interval in the African record. The authors and external experts report these specimens are among the best candidates yet for populations lying near the root of the split that led to modern humans and some archaic Eurasian lineages. Further analyses, including planned palaeoproteomic work and continued field study, are reported as next steps to clarify their relationships and significance.