Fossils found in a cave shed light on where our species emerged, dating back to the time of Earth

Where did our species first emerge? Fossils discovered in Morocco dating back more than 773,000 years reinforce the theory that Homo sapiens originally appeared in Africa, scientists said in a study Wednesday.

the oldest Homo sapiens fossilsdating back more than 300,000 years, were found in Jebel Irhoud, northwest of Marrakech.

our cousins neanderthals They lived primarily in Europe, while the most recent additions to the family, the Denisovans, roamed Asia.

This has created an enduring mystery: who was the last common ancestor of Homo sapiens and our cousins, before the family tree split into different branches?

This divergence is believed to have occurred between 550,000 and 750,000 years ago.

Until now, the main hominin fossils from that time were found in Atapuerca, Spain.

They belonged to a species called “Homo antecessor”, which dated back about 800,000 years and had characteristics that were a mix of the oldest Homo erectus and others more similar to Homo sapiens and our cousins.

This sparked a controversial debate over whether our species originally emerged outside of Africa, before returning there.

There was “a gap in the fossil record of Africa,” French paleoanthropologist and lead author of the study, Jean-Jacques Hublin, told News.

The research published in the journal Nature fills that gap by finally establishing a firm date for the fossils discovered in 1969 inside a cave in the Moroccan city of Casablanca.

For three decades, a Franco-Moroccan team unearthed hominid vertebrae, teeth and jaw fragments that have baffled researchers.

Researchers said a thigh bone found in the cave had bite marks suggesting the person may have been killed or eaten by a predator, Reuters news agency reported.

“Only the femur shows clear evidence of carnivorous modification (rhodis and tooth marks) indicating consumption by a large carnivore,” Hublin told Reuters. “However, the cave appears to have been primarily a carnivore den that the hominids used only occasionally. The absence of tooth marks on the jaws does not imply that other parts of the bodies were not consumed by hyenas or other carnivores.”

A thin lower jaw discovered in 2008 was particularly disconcerting.

“Hominids who lived half a million or a million years ago generally didn’t have small jaws,” Hublin said.

“We could clearly see that it was something unusual and we wondered how old it could be.”

However, numerous efforts to determine his age failed.

When the Earth’s magnetic field reversed

The researchers then tried a different approach.

From time to time, the Earth’s magnetic field changes. Until the last reversal, 773,000 years ago, our planet’s magnetic north pole was close to the geographic south pole.

Evidence of this change is still preserved in rocks around the world.

The Casablanca fossils were discovered in layers corresponding to the time of this inversion, allowing scientists to establish a “very, very precise” date, Hublin said.

This discovery eliminates the “absence of plausible ancestors” of Homo sapiens in Africa, he added.

Antonio Rosas, a researcher at Spain’s National Museum of Natural Sciences, said this adds “weight to the increasingly prevalent idea” that the origins of our species and the last common ancestor of Homo sapiens and Neanderthals/Denisovans lie in Africa.

“This work also suggests that the evolutionary divergence of the H. sapiens lineage could have begun earlier than conventionally assumed,” Rosas, who was not involved in the research, commented in Nature.

Like Homo antecessor, the Casablanca fossils have a mix of characteristics from Homo erectus, ourselves, and our cousins.

But although they are clearly closely related, the Moroccan and Spanish fossils are not the same, which Hublin says is a sign of “populations that are in the process of separating and differentiating.”

The Middle East is considered to have been the main migratory route for hominids out of Africa; However, sinking sea levels at certain times could have allowed crossings between Tunisia and Sicily, or through the Strait of Gibraltar.

Therefore, the Casablanca fossils are “further evidence supporting the hypothesis of possible exchanges” between North Africa and southwestern Europe, Hublin said.

The study was published just weeks after scientists said the newly discovered fossils prove that a Mysterious foot found in Ethiopia belongs to a little-known and recently named ancient human relative that lived alongside the famous Lucy’s species.