Until a few days ago, the map of human evolution in Africa had a major “black hole” of knowledge. We had data that indicated that the Homo sappiens It emerged about 300,000 years ago thanks to the remains of Jebel Irhoud and we knew that our most distant ancestors ran around the continent a million years ago. But in the middle there was no information about it.
A new study. To address this gap, an international team led by paleoanthropologist Jean-Jacques Hublin has published in Nature a discovery that not only fills that void, but also It forces us to recalibrate when and how we begin to be “us.”
They have finished putting the focus on a quarry in Casablanca (Morocco) where the remains of what could be our oldest direct ancestors have appeared.
A treasure under the quarry. This site is not entirely new, but what has been revealed is. In the so-called Grotte à Hominidés Researchers have been able to find three jaws (two from an adult and one from a child), isolated teeth, vertebrae and a fragment of a femur.
This femur the truth is that It has a macabre history behind it, since it has marks of hyena teeth, which suggests that these individuals were not buried, but rather were the feast of the predators that lived in this cave.
But the interesting thing about these remains is undoubtedly in their morphology, which presents very primitive features, but, at the same time, their teeth and the structure of their jaw show “derived” features that already point directly towards the Homo sapiens.
Technology behind the date. In paleoanthropology the difference between an “interesting find” and a “revolution” usually lies in the dating of the discovery. Something that today can be done with great precision thanks to the combination of geology with modern techniques.
In this case, the researchers used the technique of magnetostratigraphy to analyze 180 sediment samples to identify the Brunhes-Matuyama transition. This transition in the sediments is fundamental, since it is a global event that occurred about 773,000 years ago, when the Earth’s magnetic field was invested (magnetic north became the current geographic north pole), and which is useful for dating sediment samples.
Its dating. By finding the fossils right in this stratum that we have so well studied along with when it occurred, we can now set a date of 773,000 years with a margin of error of just 4,000 years for these fossils.
And although 4,000 years may seem like a large margin of error, the reality is that in geological terms it is like telling the time in a very exact way (even with its seconds).
The end of the reign of Atapuerca. For years, the Homo antecessor from Atapuerca (Spain) was proposed as the common ancestor of sapiens and Neanderthals, to make sense of this void. But this discovery completely changes the narrative we have on the table.
Hublin’s study suggests that these Moroccan hominids are evolutionarily closer to us than the Homo antecessor. In this way, while the Spanish fossils seem like a lateral branch that adapted to the European environment, those from Casablanca would represent the main African lineage. Something that also fits with current genetic studies that place the divergence between modern humans and Neanderthals approximately 800,000 years ago.
It doesn’t fit everyone. Like any great advance, this scientific article has raised a lot of dust in the sector, since not all experts are convinced that the origin is exclusively African. On the one hand, María Martinón-Torres, director of CENIEH, criticism The study ignores recent Asian fossils (such as those from Harbin or Hualongdong in China) that also show modern features at ancient dates.
On the other hand, Antonio Rosas, from the CSIC, raises a reasonable doubt: If these fossils are close to the root of the common ancestor, why don’t they show traits that also point towards Neanderthals?
What it means for the future. This discovery in Casablanca breaks the paradigm that the Homo sapiens It was a recent “invention” from 300,000 years ago. Instead, it suggests that it was a much longer, more complex and deeply rooted process in North Africa.
What is happening right now is that Hubblin’s team is continuing to dig. With current dating technology and the possibility of finding more cranial fragments, the next step will be to try to extract ancient proteins from the teeth to confirm, through paleoproteomics, if the DNA confirms what already seems obvious: that the bones are older than we think.
Images | Ibrahim Jonathan
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