Ancient bones discovered in a cave in Casablanca, Morocco could fill in some gaps about human evolution.
Known as the Grotte à Hominidés, the cave contains an assemblage of jaws, teeth and vertebrae dating back 773,000 years ago – a period close to the time when modern human lineages began to diverge from their common ancestors of Neanderthals and Denisovans.
Detailed analysis shows that the remains belong to a group of early African hominins that lived near this evolutionary crossroads, showing a mix of traits later seen in modern humans and Neanderthals, as well as more ancient traits inherited from earlier members of the genus Homo.
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This discovery helps anchor human origins firmly in Africa, thus avoiding the confusion caused by Africa. human ancestors Hominin fossils from Europe date to a similar period.
One of the mandibles photographed during excavation. (JP Raynal, Casablanca Prehistory Project)
Anthropologist Jean-Jacques Hublin of Germany’s Max Planck Institute for Evolutionary Anthropology, who led the study, said: “Fossils from hominin grottoes are probably the best candidates for the African populations we have found so far that were located near the roots of this common ancestor, reinforcing the idea that our species originated deeply in Africa.”
Humankind’s evolutionary history is messy, complex, and much of it has been lost to the ravages and decay of time. The evidence we do have is often fragmented and difficult to interpret—a task made even trickier by problems with precise dating. As a result, many hominin fossils range in age.
The Grotte à Hominidés fossils are all different, which makes them exciting.
Earth’s magnetic poles flip frequently. These events are recorded geologically as the ferromagnetic material in the rock rearranges itself. The most recent flip, the Matsuyama-Brunhus reversal, occurred about 773,000 years ago and probably lasted for at least a few thousand years.
It’s been recorded very, very clearly in the sediments of hominid caves, and fossilized bones have been found in the same layers as magnetic reversal signatures. This very clearly and precisely dates them to 773,000 years ago—the time frame that most anthropologists believe that the process of human diversification was underway.
This is part of the picture. Based on the sediments in which the bones were found, we know they belong to a group of people who lived at a critical moment in human history.
The next step for the researchers is to take a closer look at the bones themselves and see what they reveal about the population.
The 773,000-year-old human skeleton found in the Grotte à Hominidés includes jaws, teeth and vertebrae. (Hablin et al., nature2025)
The ancient human bones in the cave include two adult jaws and one jaw belonging to a very young child. There are also a handful of teeth and vertebrae, as well as part of a femur.
Although these remains are few in number, they can tell us a lot. For example, the jaws are long, low, narrow, and have recessed joints—characteristics that are different from modern humans and Neanderthals and more similar to older members of the genus HomoFor example Homo erectus.
The teeth themselves, on the other hand, were smaller and more similar to modern human teeth.
CT scans allow researchers to study a structure inside the tooth called the enamel-dentin junction. The shape of the structure bears some similarities to both Homo erectus and H. Ancestorsbut is significantly different from both.
“Hominid teeth retain many primitive characteristics in terms of shape and non-metric features and lack Neanderthal characteristics,” said Shara Bailey, an anthropologist at New York University.
“In this sense, they are different from human ancestorsIn some features, they began to resemble Neanderthals. Analysis of tooth morphology suggests that regional differences in human groups may have existed at the end of the Early Pleistocene. “
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Given the geographical separation H. Ancestors and the new Moroccan fossils, researchers suspect the two groups may have been different from each other, with the Grotte à Hominidés group belonging to the African lineage that later gave rise to modern humans, and H. Ancestors Represents a related sister group on the Eurasian side of the early human lineage split.
At the same time, the mixture of features in Grotte à Hominidés indicates a period of transition. Taken together, the combination of these features suggests that these fossils should be placed on an African tree trunk within the evolutionary lineage of modern humans. This population is unlikely to represent the last common ancestor between modern humans and their relatives, but it is close enough to provide new insights into how this difference unfolded.
“The origin of Homo sapiensand the precise time when their ancestral populations diverged from Neanderthals –Denisovans clades, remain the subject of debate,” the researchers wrote in their paper.
“Our results are not only consistent with the phylogenetic structure inferred from paleogenetic data, but also highlight the Maghreb as a key region for understanding the emergence of our species, strengthening the argument for African rather than Eurasian ancestry. Homo sapiens“.
The study was published in nature.
