Credit: Hamza Mehimdate, Programme Préhistoire de Casablanca
Fossils dating back 773,000 years from Thomas Quarry I in Morocco shed new light on the shared ancestry of Homo sapiens, Neandertals, and Denisovans.
An international team of researchers has identified and analysed newly discovered hominin fossils from Thomas Quarry I (Casablanca, Morocco).
Using advanced geological dating methods, the team determined that the fossils are 773,000 plus/minus 4,000 years old.
This unusually precise age estimate comes from a detailed magnetostratigraphic record that captures the Brunhes/Matuyama boundary, the most recent major reversal of Earth’s magnetic field, along with well-established time markers from the Quaternary period.
Fossils dating back 773,000 years from Thomas Quarry I in Morocco shed new light on the shared ancestry of Homo sapiens, Neandertals, and Denisovans.
An international team of researchers has identified and analysed newly discovered hominin fossils from Thomas Quarry I (Casablanca, Morocco).
Using advanced geological dating methods, the team determined that the fossils are 773,000 plus/minus 4,000 years old.
This unusually precise age estimate comes from a detailed magnetostratigraphic record that captures the Brunhes/Matuyama boundary, the most recent major reversal of Earth’s magnetic field, along with well-established time markers from the Quaternary period.
Credit: R. Gallotti, Programme Préhistoire de Casablanca
Published in Nature, the findings place these African populations near the very beginning of the evolutionary branch that later produced Homo sapiens. In doing so, the study offers important new evidence about the shared ancestry of H. sapiens, Neandertals, and Denisovans.
The study was led by Jean-Jacques Hublin (Collège de France & Max Planck Institute for Evolutionary Anthropology), David Lefèvre (Université de Montpellier Paul Valéry), Giovanni Muttoni (Università degli Studi di Milano), and Abderrahim Mohib (Moroccan Institut National des Sciences de l’Archéologie et du Patrimoine, INSAP).
Published in Nature, the findings place these African populations near the very beginning of the evolutionary branch that later produced Homo sapiens. In doing so, the study offers important new evidence about the shared ancestry of H. sapiens, Neandertals, and Denisovans.
The study was led by Jean-Jacques Hublin (Collège de France & Max Planck Institute for Evolutionary Anthropology), David Lefèvre (Université de Montpellier Paul Valéry), Giovanni Muttoni (Università degli Studi di Milano), and Abderrahim Mohib (Moroccan Institut National des Sciences de l’Archéologie et du Patrimoine, INSAP).
Decades of Moroccan-French fieldwork lead to major new discoveries
The discoveries are the result of more than thirty years of sustained archaeological and geological research carried out under the Moroccan-French Program “Préhistoire de Casablanca”. This long-running initiative has involved extensive excavations, careful stratigraphic documentation, and broad geoarchaeological studies across the southwestern area of Casablanca.
Over time, this systematic and methodical work revealed the remarkable stratigraphic, environmental, and archaeological richness of Thomas Quarry I. These efforts eventually led to the recovery of the hominin fossils and the geological sequences that form the basis of the current analysis.
As Abderrahim Mohib explains: “The success of this long-term research reflects a strong institutional collaboration involving the Ministère de la Jeunesse, de la Culture et de la Communication Département de la Culture of the Kingdom of Morocco (through INSAP) and the Ministère de l’Europe et des Affaires Étrangères of France (through the French Archaeological Mission Casablanca).”
The discoveries are the result of more than thirty years of sustained archaeological and geological research carried out under the Moroccan-French Program “Préhistoire de Casablanca”. This long-running initiative has involved extensive excavations, careful stratigraphic documentation, and broad geoarchaeological studies across the southwestern area of Casablanca.
Over time, this systematic and methodical work revealed the remarkable stratigraphic, environmental, and archaeological richness of Thomas Quarry I. These efforts eventually led to the recovery of the hominin fossils and the geological sequences that form the basis of the current analysis.
As Abderrahim Mohib explains: “The success of this long-term research reflects a strong institutional collaboration involving the Ministère de la Jeunesse, de la Culture et de la Communication Département de la Culture of the Kingdom of Morocco (through INSAP) and the Ministère de l’Europe et des Affaires Étrangères of France (through the French Archaeological Mission Casablanca).”
Credit: J.P. Raynal, Programme Préhistoire de Casablanca
The present study was also supported by the Università degli Studi di Milano (Italy), the Max-Planck Institute for Evolutionary Anthropology (Germany), the LabEx Archimède – University of Montpellier Paul Valéry, the University of Bordeaux, and the Muséum National d’Histoire Naturelle (France).
A unique geological setting: the Moroccan Atlantic coast as a Pleistocene treasure house
Jean-Paul Raynal, who co-directed the program during the excavations that uncovered the fossils, highlights the broader significance of the site.
He notes that “Thomas Quarry I lies within the raised coastal formations of the Rabat–Casablanca littoral, a region internationally renowned for its exceptional succession of Plio-Pleistocene palaeoshorelines, coastal dunes and cave systems.”
The present study was also supported by the Università degli Studi di Milano (Italy), the Max-Planck Institute for Evolutionary Anthropology (Germany), the LabEx Archimède – University of Montpellier Paul Valéry, the University of Bordeaux, and the Muséum National d’Histoire Naturelle (France).
A unique geological setting: the Moroccan Atlantic coast as a Pleistocene treasure house
Jean-Paul Raynal, who co-directed the program during the excavations that uncovered the fossils, highlights the broader significance of the site.
He notes that “Thomas Quarry I lies within the raised coastal formations of the Rabat–Casablanca littoral, a region internationally renowned for its exceptional succession of Plio-Pleistocene palaeoshorelines, coastal dunes and cave systems.”
Credit: Philipp Gunz, MPI for Evolutionary Anthropology
These landscapes were shaped by repeated sea level changes, wind-driven sedimentation, and the rapid cementation of coastal sands, processes that together created ideal conditions for preserving fossils and archaeological remains.
Because of this geological history, the Casablanca region has become one of Africa’s most important archives of Pleistocene life. The area documents early Acheulean stone tool traditions and their later developments, shifting animal communities that reflect environmental change, and multiple periods of hominin occupation.
Within this context, Thomas Quarry I, excavated into the Oulad Hamida Formation, stands out for containing the oldest Acheulean industries in north-western Africa, dated to roughly 1.3 million years ago. The site is also located near other well-known localities such as Sidi Abderrahmane, a classic reference point for Middle Pleistocene prehistory in Northwest Africa. Within this larger complex, the “Grotte à Hominidés” is especially significant.
David Lefèvre explains it is “a unique cave system carved by a marine highstand into earlier coastal formations and later filled with sediments that preserved hominin fossils in a secure, undisturbed, and undisputable stratigraphic context,” providing rare clarity about the age and setting of these early human remains.
These landscapes were shaped by repeated sea level changes, wind-driven sedimentation, and the rapid cementation of coastal sands, processes that together created ideal conditions for preserving fossils and archaeological remains.
Because of this geological history, the Casablanca region has become one of Africa’s most important archives of Pleistocene life. The area documents early Acheulean stone tool traditions and their later developments, shifting animal communities that reflect environmental change, and multiple periods of hominin occupation.
Within this context, Thomas Quarry I, excavated into the Oulad Hamida Formation, stands out for containing the oldest Acheulean industries in north-western Africa, dated to roughly 1.3 million years ago. The site is also located near other well-known localities such as Sidi Abderrahmane, a classic reference point for Middle Pleistocene prehistory in Northwest Africa. Within this larger complex, the “Grotte à Hominidés” is especially significant.
David Lefèvre explains it is “a unique cave system carved by a marine highstand into earlier coastal formations and later filled with sediments that preserved hominin fossils in a secure, undisturbed, and undisputable stratigraphic context,” providing rare clarity about the age and setting of these early human remains.
A uniquely well-dated hominin assemblage in Africa
Dating Early and Middle Pleistocene fossils is notoriously difficult, due to discontinuous stratigraphies or methods affected by considerable uncertainty. The Grotte à Hominidés is exceptional because rapid sedimentation and continuous deposition allowed to capture a high-resolution magnetic signal recorded within sediments with remarkable detail.
Earth’s magnetic field reverses polarity episodically over geological time. These paleomagnetic reversals occur worldwide and almost instantaneously on geological timescales, leaving in sediments a sharp, globally synchronous signal. The Matuyama–Brunhes transition (MBT), which occurred around 773,000 years ago, is the most recent of these major reversals and constitutes one of the most precise markers available to geologists and archaeologists.
Credit: D. Lefèvre, Programme Préhistoire de Casablanca
As Serena Perini explains: “Seeing the Matuyama–Brunhes transition recorded with such resolution in the ThI-GH deposits allows us to anchor the presence of these hominins within an exceptionally precise chronological framework for the African Pleistocene.”
The Grotte à Hominidés sequence spans the end of the Matuyama Chron (reverse polarity), the MBT itself, and the onset of the Brunhes Chron (normal polarity). Using 180 magnetostratigraphic samples – an unprecedented resolution for a Pleistocene hominin site – the team established the exact position of the reverse-to-normal switch, currently dated at 773,000 years, and even captured the short duration of the transition (8,000 to 11,000 years).
It is chronologically valuable that the sediments containing the hominin fossils were deposited precisely during this transition. Additional faunal evidence independently supports this age, affirming the primacy of magnetostratigraphy over other methods for establishing the chronology of this site.
Hominins close to the root of the Homo sapiens lineage
The hominin remains come from what appears to have been a carnivore den, as suggested by a hominin femur showing clear traces of gnawing and consumption. The assemblage includes a nearly complete adult mandible, a second adult half mandible, a child mandible, several vertebrae, and isolated teeth.
High-resolution micro-CT imaging, geometric morphometrics, and comparative anatomical analysis reveal a mosaic of archaic and derived traits. Several characteristics recall hominins from Gran Dolina, Atapuerca, of comparable age – the so-called Homo antecessor – suggesting that very ancient population contacts between north-west Africa and southern Europe may once have existed. However, by the time of the Matuyama–Brunhes transition, these populations appear to have been already clearly separated, implying that any such exchanges must have occurred earlier.
Matthew Skinner notes: “Using microCT imaging, we were able to study a hidden internal structure of the teeth, referred to as the enamel-dentine junction, which is known to be taxonomically informative and which is preserved in teeth where the enamel surface is worn away. Analysis of this structure consistently shows the Grotte à Hominidés hominins to be distinct from both Homo erectus and Homo antecessor, identifying them as representative of populations that could be basal to Homo sapiens and archaic Eurasian lineages.”
As Serena Perini explains: “Seeing the Matuyama–Brunhes transition recorded with such resolution in the ThI-GH deposits allows us to anchor the presence of these hominins within an exceptionally precise chronological framework for the African Pleistocene.”
The Grotte à Hominidés sequence spans the end of the Matuyama Chron (reverse polarity), the MBT itself, and the onset of the Brunhes Chron (normal polarity). Using 180 magnetostratigraphic samples – an unprecedented resolution for a Pleistocene hominin site – the team established the exact position of the reverse-to-normal switch, currently dated at 773,000 years, and even captured the short duration of the transition (8,000 to 11,000 years).
It is chronologically valuable that the sediments containing the hominin fossils were deposited precisely during this transition. Additional faunal evidence independently supports this age, affirming the primacy of magnetostratigraphy over other methods for establishing the chronology of this site.
Hominins close to the root of the Homo sapiens lineage
The hominin remains come from what appears to have been a carnivore den, as suggested by a hominin femur showing clear traces of gnawing and consumption. The assemblage includes a nearly complete adult mandible, a second adult half mandible, a child mandible, several vertebrae, and isolated teeth.
High-resolution micro-CT imaging, geometric morphometrics, and comparative anatomical analysis reveal a mosaic of archaic and derived traits. Several characteristics recall hominins from Gran Dolina, Atapuerca, of comparable age – the so-called Homo antecessor – suggesting that very ancient population contacts between north-west Africa and southern Europe may once have existed. However, by the time of the Matuyama–Brunhes transition, these populations appear to have been already clearly separated, implying that any such exchanges must have occurred earlier.
Matthew Skinner notes: “Using microCT imaging, we were able to study a hidden internal structure of the teeth, referred to as the enamel-dentine junction, which is known to be taxonomically informative and which is preserved in teeth where the enamel surface is worn away. Analysis of this structure consistently shows the Grotte à Hominidés hominins to be distinct from both Homo erectus and Homo antecessor, identifying them as representative of populations that could be basal to Homo sapiens and archaic Eurasian lineages.”
Credit: R. Gallotti, Programme Préhistoire de Casablanca
Shara Bailey confirms the generalized shape and traits of the Grotte à Hominidés teeth, noting that “In their shapes and non-metric traits, the teeth from Grotte à Hominidés retain many primitive features and lack the traits that are characteristic of Neandertals. In this sense, they differ from Homo antecessor, which – in some features – are beginning to resemble Neandertals. The dental morphological analyses indicate that regional differences in human populations may have been already present by the end of the Early Pleistocene”.
Shara Bailey confirms the generalized shape and traits of the Grotte à Hominidés teeth, noting that “In their shapes and non-metric traits, the teeth from Grotte à Hominidés retain many primitive features and lack the traits that are characteristic of Neandertals. In this sense, they differ from Homo antecessor, which – in some features – are beginning to resemble Neandertals. The dental morphological analyses indicate that regional differences in human populations may have been already present by the end of the Early Pleistocene”.
A new window on the last common ancestor of humans and Neandertals
This discovery highlights that Northwest Africa played a major role in the early evolutionary history of the genus Homo, at a time when climatic oscillations periodically opened ecological corridors across what is now the Sahara.
As Denis Geraads notes: “The idea that the Sahara was a permanent biogeographic barrier does not hold for this period. The palaeontological evidence shows repeated connections between Northwest Africa and the savannas of the East and South.”
The hominins from the Grotte à Hominidés are almost contemporaneous with the hominins from Gran Dolina, older than Middle Pleistocene fossils ancestral to Neanderthals and Denisovans, and roughly 500,000 years earlier than the earliest Homo sapiens remains from Jebel Irhoud. In their combination of archaic African traits with traits that approach later Eurasian and African Middle Pleistocene morphologies, the hominins from the Grotte à Hominidés provide essential clues about the last common ancestor of Homo sapiens, Neandertals, and Denisovans—estimated from genetic evidence to have lived between 765,000 and 550,000 years ago. Paleontological evidence from the Grotte à Hominidés aligns most closely with the older part of this interval.
Jean-Jacques Hublin concludes that “the fossils from the Grotte à Hominidés may be the best candidates we currently have for African populations lying near the root of this shared ancestry, thus reinforcing the view of a deep African origin for our species.“
This discovery highlights that Northwest Africa played a major role in the early evolutionary history of the genus Homo, at a time when climatic oscillations periodically opened ecological corridors across what is now the Sahara.
As Denis Geraads notes: “The idea that the Sahara was a permanent biogeographic barrier does not hold for this period. The palaeontological evidence shows repeated connections between Northwest Africa and the savannas of the East and South.”
The hominins from the Grotte à Hominidés are almost contemporaneous with the hominins from Gran Dolina, older than Middle Pleistocene fossils ancestral to Neanderthals and Denisovans, and roughly 500,000 years earlier than the earliest Homo sapiens remains from Jebel Irhoud. In their combination of archaic African traits with traits that approach later Eurasian and African Middle Pleistocene morphologies, the hominins from the Grotte à Hominidés provide essential clues about the last common ancestor of Homo sapiens, Neandertals, and Denisovans—estimated from genetic evidence to have lived between 765,000 and 550,000 years ago. Paleontological evidence from the Grotte à Hominidés aligns most closely with the older part of this interval.
Jean-Jacques Hublin concludes that “the fossils from the Grotte à Hominidés may be the best candidates we currently have for African populations lying near the root of this shared ancestry, thus reinforcing the view of a deep African origin for our species.“
The birth of modern Man
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