A team of scientists from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) recently published an important paper in PLOS ONE that sheds new light on the complex origins of Neanderthals. The paper focuses on the Middle Pleistocene Montmaurin-La Niche mandible, a fossil discovered in 1949 by Raoul Cammas in the karstic cavities of Montmaurin, located in the La Niche cave in France. This discovery provides further evidence of the intricate and non-linear evolution of Neanderthals, challenging previously held assumptions about their origins and development.
The Montmaurin-La Niche mandible, dating between 200,000 and 240,000 years ago, had been long presumed to resemble that of later European Neanderthals, particularly in the structure of the teeth. For years, it was believed that the mandible showed close morphological similarities to more recent Neanderthal fossils, providing a straightforward link to the Neanderthal lineage. However, the new research employs advanced mathematical techniques to analyze a wide variety of mandibles from different human species, including a collection of recent African fossils. The results show that the Montmaurin mandible is not as closely related to the later European Neanderthals as previously thought. Instead, it aligns more closely with some of the most archaic human specimens from Europe, such as those from Dmanisi, a famous archaeological site in Georgia. This finding complicates the traditional view of human evolution in Europe, suggesting a more complex and mosaic-like process rather than a simple linear progression.
Bermúdez de Castro, one of the leading researchers in the study, emphasized the significance of these findings, stating, “We find here an archaic mandible, and dental pieces which taxonomically are indisputably Neanderthal, which helps to support the hypothesis that the Neanderthal lineage did not evolve linearly but in mosaic.” This observation supports the growing theory that the Neanderthal lineage evolved through a more varied and intricate process, involving multiple stages and possibly different population groups, rather than through a straightforward, gradual transition from a single common ancestor.
The Montmaurin-La Niche mandible has long been a key piece in the study of human evolution in Europe. For decades, it was regarded as the oldest human fossil discovered in France, and it has been the subject of numerous comparative studies. One of the most notable works was the 1977 description by G. Billy and Henri V. Vallois, which was based on the scientific knowledge and evolutionary theories of the time. At that point, the prevailing view of human evolution in Europe was largely linear, with the Neanderthals seen as a distinct and homogenous group that gradually evolved over time.
However, the complexity of human evolution in Europe is becoming increasingly apparent. As new discoveries are made and new methodologies are applied to existing fossils, scientists are revisiting old assumptions about the development of early humans. The new paper, titled A reassessment of the Montmaurin-La Niche mandible (Haute Garonne, France) in the context of European Pleistocene human evolution, authored by Mario Modesto, María Martinón-Torres, Marina Martínez de Pinillos, and others, emphasizes the evolving nature of our understanding of this period in prehistory.
A key argument presented in this study is the growing recognition that multiple hominin lineages may have coexisted in Europe during the Middle Pleistocene. This hypothesis, once controversial, is gaining increasing support as new evidence points to the possibility of interbreeding, genetic drift, and prolonged periods of isolation among different human groups. Such processes, the authors suggest, were likely a common feature of human evolution during this period. This new perspective challenges older, linear models of human evolution, such as the “accretion” hypothesis, which suggested that Neanderthals evolved in a slow, continuous process from earlier human ancestors. Instead, the evidence now points toward a more dynamic and varied picture of human evolution, with different hominin groups interacting and influencing each other in complex ways.
The study of the Montmaurin-La Niche mandible highlights the ongoing challenges in understanding the origins and development of the Neanderthals. While the fossil is clearly Neanderthal in terms of its dental features, its archaic characteristics suggest that the lineage did not follow a simple, linear trajectory. The presence of these more ancient traits in the mandible implies that Neanderthals may have evolved through a more complex pattern of genetic exchange, adaptation, and isolation over time.
The authors of the paper also caution that the question of when and how the “classic” Neanderthals emerged in the Late Pleistocene remains unsettled. Despite decades of research, many key questions about the Neanderthal lineage remain unanswered. The Montmaurin-La Niche mandible, with its mix of archaic and Neanderthal characteristics, is just one more example of the uncertainties that persist in the study of human evolution.
Bermúdez de Castro concludes the study by noting, “The appearance of the classic Neanderthals in the Late Pleistocene is a question by no means finally settled. There remain many open questions, and the Montmaurin-La Niche mandible now joins the list of X-files.” This statement underscores the continued mystery surrounding the origins of the Neanderthals and the ongoing debates in paleoanthropology about the nature of their evolution.
More information: Amélie Vialet et al. A reassessment of the Montmaurin-La Niche mandible (Haute Garonne, France) in the context of European Pleistocene human evolution, PLOS ONE (2018). DOI: 10.1371/journal.pone.0189714