Remains of hominids dating back 770,000 years found in Morocco reveal an African lineage prior to Homo sapiens
A team of international researchers discovered fossil remains of hominids dating back 773,000 years in the Moroccan city of Casablanca, providing clues about the common origin of modern humans, Homo sapiens. The discovery was presented on Wednesday at a conference in Rabat led by the Minister of Culture, Mohamed Mehdi Bensaid, and some of the researchers who participated in this discovery, which was published today in the journal Nature.
The discovery was made by a team of researchers from Morocco, France, Italy, Spain, and Germany. Thus, the African, rather than Eurasian, origin of Homo sapiens is now more strongly supported thanks to the description and dating of fossil remains found at the Casablanca site, which provide new evidence that Africa is the origin of the human species.
Scientists believe that the last common ancestor of modern humans, Neanderthals, and Denisovans (named after the caves in Siberia where they were found) lived between 765,000 and 550,000 years ago. The question to be answered is where they lived.
Discoveries such as Homo antecessor in the Sierra de Atapuerca (Burgos, northern Spain), dated to 800,000 years ago, suggested that this ancestral link had occurred in Europe.
However, the Moroccan fossils described on Wednesday reinforce the theory that the hominid that served as a link between Neanderthals and sapiens came from Africa. The remains described are an almost complete adult jaw, a second half of an adult jaw, a child's jaw, numerous teeth, and vertebrae.
The director of the Franco-Moroccan research mission “Prehistory of Casablanca,” Abderrahim Mohib, explained that the material studied consisted of several human jaws, one of which belonged to a child, dental remains, and post-renal remains.
All of them were unearthed in 2008 in a cave known as “Grotte à Hominidés” at the Thomas Quarry I site in Casablanca. “The hominins discovered in this cave are the best candidates for the common origin of modern man because they combine archaic characteristics observed in Homo erectus with more modern derived features,” Mohib said during the press conference, where he also presented the fossil remains studied.
The Moroccan scientist indicated that the findings fill an important gap in the African fossil record, at a time when, according to paleogenetic data, the evolutionary separation occurred between the African ancestors of Homo sapiens and the human groups that migrated to Eurasia and later gave rise to Neanderthals and Denisovans.
“The fossils present an original combination of primitive and more evolved characteristics, which indicates human populations close to this phase of bifurcation between the human lineages of Africa and Europe (...). This confirms the antiquity and depth of the African roots of our species (Homo sapiens) and underlines the key role of North Africa in the major stages of human evolution,” he said.
The oldest known human remains of Homo sapiens, dating back nearly 315,000 years, were discovered in 2017 at the archaeological site of Jbel Irhoud in southern Morocco.
New technologies for fossil dating
Using a modern technology called high-resolution magnetostratigraphic dating, researchers studied both the fossil remains and the surrounding sediments, concluding that they date back some 773,000 years, one of the authors, Asier Gómez, a researcher at the University of the Basque Country (northern Spain), told EFE.
Gómez was part of the large team responsible for describing the remains. Specifically, he studied the cervical and thoracic vertebrae found and compared them with other similar hominid pieces previously studied.
The key is that the Casablanca fossils are morphologically different from the Homo antecessor found in Atapuerca, which implies the existence of a regional differentiation between Europe and North Africa since the late Early Pleistocene (between 1.8 million and 780,000 years ago).
The Casablanca remains show a mixture of ancient features, observed in species such as Homo erectus, and other modern features, found in Homo sapiens and Neanderthals. This indicates that they correspond to the period when Eurasian and African human lineages began to diverge at the end of the early Pleistocene.
The researcher from the Department of Geology at the University of the Basque Country emphasizes that the highly accurate description of the remains was possible not only thanks to new technologies, but also to the multidisciplinary nature of the research, which included experts in numerous scientific fields, something “fundamental to understanding human evolution.”
Filling a key gap
“This study fills a key gap in the African record just near the interval where genetics places the separation between the lineage that will end in Homo sapiens and Neanderthals,” says Juan Ignacio Morales, a researcher at the Catalan Institute of Human Paleoecology and Social Evolution.
“The hominins from Casablanca could be understood, in general terms, as an African equivalent of Homo antecessor, in the sense that both would represent evolved forms of Homo erectus at two extremes of the Mediterranean at similar times, with an anatomy that combines primitive and modern features,” says the researcher.