Early development of the Neanderthal ribcage reveals a different body shape at birth compared to modern humans

Ontogenetic studies provide clues for understanding important paleobiological aspects of extinct species. When compared to that of modern humans, the adult Neanderthal thorax was shorter, deeper, and wider. This is related to the wide Neanderthal body and is consistent with their hypothetical large requirements for energy and oxygen. Whether these differences were already established at birth or appeared later during development is unknown. To delve into this question, we use virtual reconstruction tools and geometric morphometrics to recover the 3D morphology of the ribcages of four Neanderthal individuals from birth to around 3 years old: Mezmaiskaya 1, Le Moustier 2, Dederiyeh 1, and Roc de Marsal. Our results indicate that the comparatively deep and short ribcage of the Neanderthals was already present at birth, as were other skeletal species-specific traits. This morphology possibly represents the plesiomorphic condition shared with Homo erectus, and it is likely linked to large energetic requirements.

Expression of Nonmetric Dental Traits in Western European Neanderthals

Neanderthals of Western Europe lived across distinct ecogeographic zones from Marine Iso-tope Stage 7 to 3. Differences in dental morphology from seven Western European sites are compared in terms of ecogeography and chronology.Neanderthals (n = 12) along a north-south gradient were examined. These included the Meuse River Basin of Belgium (Engis 2 and Scladina 1-4A ), Southwest France (Pech de l'Azé 1 and Roc de Marsal), the Pyrenees (Malarnaud and Montmaurin), and the Mediterranean (Hortus). Montmaurin is the oldest, followed by Scladina 1-4A and Malarnaud, whereas the others are younger.Dental casts were prepared from Neanderthal permanent and deciduous dentition. These were de-scribed and scored, according to the ASUDAS. Comparisons of dental traits with respect to ecogeo-graphic regions and chronological categories were constructed.Unusual dental features observed include the anterior fovea, entoconulid, metaconulid, and Cara-belli’s cusp. Dental traits that distinguish ecogeographic regions are the expression of the M1 hypocone and metaconule, whereas the hypoconulid and Carabelli’s cusp separate chronological categories. Dif-ferences are present for the entoconulid and metaconulid in both comparisons.Neither chronology nor ecogeography fully explains the results. Similarities in dental traits exist between Roc de Marsal, Pech de l’Azé 1 and Engis 2, and secondarily within the Hortus assemblage.