Earliest evidence of caries lesion in hominids reveal sugar-rich diet for a Middle Miocene dryopithecine from Europe

Abstract

The formation of dental caries is mainly caused by dietary habits and therefore, may contain information for dietary reconstructions of fossil hominids. This study investigates the caries lesion in the 12.5 Ma old type specimen of Dryopithecus carinthiacus Mottl 1957 (Primates, Hominidae) from St. Stefan (Austria). Potential food sources are identified on associated palynological data, which allow conclusions about food quality, sugar availability and the hominid metabolism during the Middle Miocene. Using micro computed tomography (μCT) and scanning electron microscopy (SEM) we provide a detailed analysis and characterization of the individuals’ caries type. Its lesion is compared with a dataset of 311 wild chimpanzees, indicating morphological and etiological differences in caries formation between both species. The affected molar of D. carinthiacus reveals features known from severe dental caries in humans: (1) Cavitation with steep walls and smooth surface; (2) Reparative dentine at the roof of the pulp chamber; (3) Sclerotic dentine below the cavitation; (4) Association with dental calculus and (5) Unilateral usage of the healthy right tooth row. Its advanced primary caries, initiating on the intact enamel surface, indicates a frequent intake of highly cariogenic sugar-rich fruits, which likely exceeds the frugivory of extant chimpanzees. This finding corresponds with the associated palynological record, which infers a habitat with nearly year-round supply (9–10 months/year) of high quality foods (>carbohydrates; < fibers). Our conclusions challenge the model of a step-wise increase in dietary quality during hominid evolution and support the uricase hypothesis, which discusses the hominid autapomorphy of a fructose-based fat accumulation for periods of starvation. This model receives further validation by the identification of soft-tissue preservation, interpreted as fossilized white adipose cells, in the articulated hominid skeleton of Oreopithecus bamboli from Italy.

Dental caries in wild primates: interproximal cavities on anterior teeth

“…Dietary and behavioral differences are known between male and female chimpanzees (Gilby et al, 2017; Nakamura et al, 2015; Wrangham and Smuts, 1980). Pregnancy and differences in oral pH, saliva, physiology, life history, and microbiome between the sexes may also be predisposing factors (e.g., Fuss et al, 2018; Lukacs and Largaespada, 2006; Stoner, 1995). The results of the present study support other research suggesting sex differences in caries rates among the great apes, although the present sample of gorillas did not show significant differences.…”

“…Recent literature has shown caries is not as rare as previously thought in fossil hominin and extant great apes (e.g., Arnaud et al, 2016; Lacy, 2014; Lacy et al, 2012; Lanfranco & Eggers, 2012; Liu et al, 2015; Margvelashvili et al, 2016; Miles & Grigson, 2003; Stoner, 1995; Towle et al, 2019; Trinkaus et al, 2000). There is also growing evidence that caries was common in other extinct primates (e.g., Fuss et al, 2018; Han and Zhao, 2002; Selig and Silcox, 2020). This study adds further evidence that caries has likely been relatively common in many primate lineages.…”

Dental caries in human evolution: frequency of carious lesions in South African fossil hominins

“…Honey is commonly consumed in many recent hunter-gatherer groups, and may therefore also be a potential factor involved in caries formation (Pontzer et al, 2018). More broadly, caries has also been found to be relatively prevalent in other wild great apes, and a lesion has been described in a Middle Miocene hominid (Stoner, 1995;Miles & Grigson, 2003;Fuss et al, 2018). The relatively high rate of caries may therefore be broader and be a hominid characteristic, although clearly there is much variation between species which allows dietary and behavioral inferences for fossil samples.…”

The Precarious State of Subsistence: Reevaluating Dental Pathological Lesions Associated with Agricultural and Hunter-Gatherer Lifeways

“…Variability in caries experience (and more broadly in oral pathology) is well documented by time, space, and subsistence regime. Carious lesions have been found on fossil hominins as far back as 1.77 Ma, including several individuals from Dmanisi (Margvelashvili et al 2016) or even further back to 12.5 Ma on the type specimen of Dryopithecus carinthiacus (Fuss, Uhlig, and Böhme 2018). Instead of using the presence, distribution, and severity of oral pathology lesions in individuals or across skeletal samples such as these paleontological cases illustrate, bioarchaeologists are generally obsessed with broad comparisons of pathology frequencies to make assumptions about, and link, pathology to diet and subsistence patterns in past human groups.…”