Mandibular morphology and the Mesolithic-Neolithic transition in Westernmost Iberia

Neolithic farming and animal husbandry were first developed in the Near East ~ 10,000 BCE and expanded westwards, reaching westernmost Iberia no later than 5500 BCE. It resulted in major social, cultural, economic and dietary changes. Yet, the impact of this change on human mandibular morphology in Iberia is yet to be assessed, which is regrettable because mandible form is impacted by population history and diet. In this study we used Mesolithic to Chalcolithic Iberian samples to examine the impact of this transition on mandibular morphology. We also compared these samples with a Southern Levantine Chalcolithic population to assess their relationship. Lastly, we assessed dental wear to determine if the morphological differences identified were related to the material properties of the diet. We found differences between samples in mandibular shape but not size, which we attribute to contrasting population histories between Mesolithic and later populations. Some differences in the severity of dental wear were also found between Mesolithic and later Iberian samples, and smaller between the Mesolithic Iberians and southern Levantines. Little relationship was found between wear magnitude and mandibular shape. Altogether, our results show that the Mesolithic-Neolithic Iberian transition resulted in a meaningful change in mandibular morphology, which was likely driven more by population history than by dietary change.

A lunate-triquetral coalition from a commingled funerary context from the Chalcolithic Perdigões ditched enclosures of Portugal

Carpal coalitions, resulting from a failure of separation of the cartilaginous precursors of the carpal bones during gestation, may be osseous or non-osseous. Even though lunate-triquetral coalitions are the most common of all carpal coalitions there is only one previous palaeopathological report of such a coalition. This study presents a non-osseous lunate-triquetral coalition found amongst the mostly cremated commingled bones from a Chalcolithic pit at Perdigões (Portugal). The cremated bones show evidence of burning at varying but mostly at generally high temperatures. The perfect articulation between these right bones and pinpoint pitting in the lunate-triquetral joint were crucial for the identification of this congenital condition. Carpal coalitions are more frequent in African than European populations. Artifacts produced from ivory of African origin were found in Perdigões, however it is not possible to establish the ancestry of this individual.

Unilateral absence of mandibular condyle in a Bronze Age male skeleton from Portugal

In 2009, a pit burial dated to the Bronze Age was excavated in Monte do Gato de Cima 3 (Portugal). The purpose of this paper is to describe the pathological absence of the left mandibular condyle noted in an adult male skeleton and to discuss possible diagnoses, including subcondylar fracture, cystic defect, congenital absence, condylar aplasia and mandibular condylysis. The most likely explanation for the pathological alteration is subcondylar fracture with non-union. Although the occurrence of non-union and slight osteoarthritic alterations in the left glenoid fossa were evident, this mandible was likely functional, as can be inferred from dental wear and muscle attachment sites. This trauma probably occurred before adult age when remodelling capacity is still high. Thus, bones and muscles adequately compensated for the trauma and only minor asymmetry developed. Consequently, this injury seems not to have greatly influenced masticatory functions. This is in accordance with clinical data, which demonstrate that, in growing patients, conservative treatment (non-surgical) results in good remodelling and patient recovery. In addition, in the few paleopathological cases published, the healing capacity of these types of mandibular fractures seems to be good, as can be inferred by evidence from the bone.

Chronic mercury exposure in Late Neolithic/Chalcolithic populations in Portugal from the cultural use of cinnabar

Cinnabar is a natural mercury sulfide (HgS) mineral of volcanic or hydrothermal origin that is found worldwide. It has been mined prehistorically and historically in China, Japan, Europe, and the Americas to extract metallic mercury (Hg⁰) for use in metallurgy, as a medicinal, a preservative, and as a red pigment for body paint and ceramics. Processing cinnabar via combustion releases Hg⁰ vapor that can be toxic if inhaled. Mercury from cinnabar can also be absorbed through the gut and skin, where it can accumulate in organs and bone. Here, we report moderate to high levels of total mercury (THg) in human bone from three Late Neolithic/Chalcolithic (5400–4100 B.P.) sites in southern Portugal that were likely caused by cultural use of cinnabar. We use light stable isotope and Hg stable isotope tracking to test three hypotheses on the origin of mercury in this prehistoric human bone. We traced Hg in two individuals to cinnabar deposits near Almadén, Spain, and conclude that use of this mineral likely caused mild to severe mercury poisoning in the prehistoric population. Our methods have applications to bioarchaeological investigations worldwide, and for tracking trade routes and mobility of prehistoric populations where cinnabar use is documented.