Spotlight on our members' work: Prehistory Matters

In this Spotlight of the Month, we’re presenting you two recent publications on prehistoric case studies by three of our highly experimented members: one regards paleopathological traces on a Late Neolithic Mandibular Condyle by Caroline Polet and Frank L'Engle Williams; the other one examines a Late Neandertal lower left P3 by Michel Toussaint and colleagues.

Both articles analyzed human remains from rockshelters or caves from the Meuse River system, in Central Belgium, where hundreds of similar archaeological sites are known.

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Caroline Polet & Frank L'Engle Williams : article on a mandibular condyle

Dr. Caroline Polet is a physical anthropologist working at the Royal Belgian Institute of Natural Sciences. She regularly studies human skeletons excavated by fellow archaeologists in Belgium and abroad.

Dr. Frank L’Engle Williams is a professor in palaeoanthropology at Georgia State University (Atlanta). He’s also specialized in primates, hominids and dental microwear.

They recently worked on a Late Neolithic mandible together, in order to understand its asymmetrical morphology, including the aetiology and biomechanical implications for the deceased.

 

Published article: A secondary mandibular condylar articulation and collateral effects on a Late Neolithic mandible from Bois Madame rockshelter in Arbre, Belgium, International Journal of Paleopathology 16 (2017): 44-49.

 

Bois Madame rockshelter, situated in Arbre (Belgium), hosted a Late Neolithic collective burial excavated in the 20th century. At least 57 individuals were identified: 38 adults and 19 immature individuals. It is dated back to the end of the fourth millennium BP (circa 4000 years BP) just prior to the Bronze Age. The most complete mandible, noticed amongst the human remains, presents a dysplasia of its right condylar head. It belonged to an adult (probably a man).

Polet and Williams studied the mandible at the Laboratory of Anthropology of the Royal Belgian Institute of Natural Sciences in Brussels. The analysis was carried out by macroscopical examination and by radiological observation of the bone in order to identify differences in mineral density.

The dysplasia exhibits antemortem modifications of bones and muscle attachments. Indeed, it consists in a secondary articulation of the condylar head, an enlarged gonial eversion, extensive masseter rugosities, exaggerated medial pterygoid insertions, pronounced exostosis of the mylohyoid ridge as well as deformation of the incisal alveolus curvature. It only affected the right side of the mandible. Unfortunately, the matching joint of the temporal bone was not recovered. Dental attrition is bilateral, almost symmetrical.

Several factors could have contributed to the asymmetry of this individual’s mandible. First, it could be a congenital condition such as a condylar deformity or the result of prenatal craniofacial anomalies. It could also be a result of different acquired conditions, such as a multilocular cyst or age-related osteoarthritis. Injuries were also taken under consideration, including parturition injuries and falls or accidents during childhood/adolescence.

The most probable conclusion is that the morphology of this mandible resulted from an early adolescence injury to the mental region. This fall or blow would have partially dislocated the right mandibular condyle. The subsequent stress would have lead to the formation of a secondary condylar articulation, as well as pronounced unilateral muscular involvement for the right side of the face. All these changes ultimately resulted in a visible asymmetry of the mandible. This find indicates that the Neolithic food producers coped with adverse conditions involving the masticatory system.

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Michel Toussaint & colleagues: article on a Neandertal tooth

Michel Toussaint is a retired lecturer in palaeoanthropology as well as an expert in prehistoric bones and teeth. Here is one of his many works on Palaeolithic hominid remains from the Meuse River Basin.

 

Published article: The Late Neandertal permanent lower left third premolar from Walou Cave (Trooz, Belgium) and its context, American Journal of Physical Anthropology 164/1 , 2017: 193-202 (doi: 10.1002/ajpa.23252).

Toussaint and colleagues discuss the particularities of a hominin premolar (P3L) found in the Walou Cave in the Meuse River Basin (Belgium) in 1997.  The find was associated to Mousterian lithic materials in a layer dated to 40 000 - 38 000 years BP.

The research framework consists in the debate on the replacement and possible chronological overlap for Neandertals and Homo sapiens between 40 000 and 35 000 years BP (Middle-Upper Paleolithic transition). Recent studies, reassessing anthropological remains from Spy and Goyet, yielded interesting results, which suggest a late survival of Neandertals in the Meuse Basin (Semal et al. 2009) [By the way, this research's authors are presented in a recent post by Palaeochron]. The Late Pleistocene datation of archaeological layers, at Walou Cave, thus can bring great insights into the knowledge of prehistoric populations, especially in the Meuse River Basin.

The tooth is a well preserved permanent lower left third premolar, which probably belonged to an adult. The crown was complete but one root was damaged postmortem.

The aims of this study consisted in the taxonomical attribution of the tooth and determination of the individual’s diet. Methods used for these matters were respectively comparative morphometric analyses and stable isotope analyses. Indeed, seven morphological features were scored occlusally.  Crown diameters were recorded and root lengths were estimated. To complement this, a 2-dimensional morphometric approach was used to further observe the occlusal surface. Comparative dataset consisted in Neandertals, Middle Paleolithic, Upper Paleolithic as well as recent historical human remains. Also, collagen was extracted from a dentine sample of the tooth to identify the main protein sources in this individual’s diet.

Results show that the Walou premolar is significantly different from modern human dentition. Dental metrics place the premolar within the Neandertal range of variation. Most scored traits for the occlusal morphology correspond to what one would find in Neandertals and early modern humans (from Pleistocene). Two particularly significant features, i.e. a small lingually displaced occlusal polygon and an asymmetric lingual outline (94% prevalence), are typically not observed in modern human third premolars, but is common in Neandertal lineage.  

Carbon and nitrogen isotope analyses indicate that the Walou individual, just like other Neandertals, essentially consumed proteins from terrestrial food sources.

These finds confirm the presence of Neandertals in the Meuse River Basin after 40 000 BP and producing Mousterian lithic artifacts.

trauma proteins assymetry dysplasia isotopes radiography collective burial rockshelters caves Meuse River Basin Meuse Neolithic premolar mandible Neandertal Michel Toussaint Frank L'Engle Williams Caroline Polet physical anthropology Prehistory