Comparative analysis of dentognathic pathologies in the Dmanisi mandibles

Abstract

Objectives: Due to the scarcity of the fossil record, in-vivo changes in the dentognathic system of early Homo are typically documented at the level of individual fossil specimens, and it remains difficult to draw population-level inferences about dietary habits, diet-related activities and lifestyle from individual patterns of dentognathic alterations. The Plio-Pleistocene hominin sample from Dmanisi (Georgia), dated to 1.77 million years ago, offers a unique opportunity to study in-vivo changes in the dentognathic system of individuals belonging to a single paleodeme of early Homo. Materials and Methods: We analyze dentognathic pathologies in the Dmanisi sample, and in comparative samples of modern Australian and Greenlander hunter-gatherer populations, applying clinical protocols of dentognathic diagnostics. Results: The Dmanisi hominins exhibit a similarly wide diversity and similar incidence of dentognathic pathologies as the modern human hunter-gatherer population samples investigated here. Dmanisi differs from the modern population samples in several respects: At young age tooth wear is already advanced, and pathologies are more prevalent. At old age, hypercementosis is substantial. Discussion: Results indicate that dentognathic pathologies and disease trajectories are largely similar in early Homo and modern humans, but that the disease load was higher in early Homo, probably as an effect of higher overall stress on the dentognathic system. Key words: aging, tooth wear, caries, periodontitisThe Plio-Pleistocene site of Dmanisi has yielded a large sample of hominin fossils associated with abundant and diverse faunal remains and Mode I stone artifacts (Gabunia et al. 2001;Ferring et al. 2011;Mgeladze et al. 2011). Occupation of the site began shortly after 1.85 Ma. The fossil hominin finds are dated to 1.77 Ma (Ferring et al. 2011). Dmanisi thus represents the earliest evidence of Homo outside of Africa. The well-preserved cranial, mandibular and postcranial remains of five individuals are unique in offering detailed insights into patterns of morphological variation within a paleodeme of early Homo, and into patterns of growth and aging Margvelashvili et al. 2013;Zollikofer et al. 2014). The craniomandibular morphology of the Dmanisi paleodeme has been described previously (Gabunia and Vekua 1995;Gabunia et al. 2000;Gabunia et al. 2001;Gabounia et al. 2002;Lordkipanidze et al. 2005;Lordkipanidze et al. 2006;Rightmire et al. 2006;Rightmire and Lordkipanidze 2010;Lordkipanidze et al. 2013;Margvelashvili et al. 2013). Cranial and mandibular morphological variation within the Dmanisi paleodeme is wide, but well within the range of variation seen in modern humans populations, and in populations of chimpanzee subspecies (Skinner et al. 2006;Lordkipanidze et al. 2013;Margvelashvili et al. 2013;Zollikofer et al. 2014). Variation in size, shape and dentognathic features among the Dmanisi mandibles has received special attention and has been studied to address questions of phylogeny, taxonomy, sexual dimorphism, die...

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

“…That said, all carious lesions ultimately share an etiology that is based on the presence of certain cariogenic bacteria and fermentable carbohydrates (Clarkson et al, 1987). Clearly, therefore, given the results of this and other recent studies (Grine et al, 1990;Trinkaus et al, 2000;Lanfranco & Eggers, 2012;Lacy et al, 2012;Humphrey et al, 2014;Lacy, 2014;Liu et al, 2015;Arnaud et al, 2016;Margvelashvili et al, 2016;Towle, 2019), cariogenic bacteria were prevalent in many, if not all, hominin species.…”

“…In the hominin lineage it is often suggested that caries is a modern disease and is scarce or absent in past hominin groups, usually justified by inferring dietary or oral bacterial differences between present day and ancient hominin populations (Brothwell, 1963;Armelagos & Cohen, 1984;Hildebolt & Molnar, 1991;Tillier et al, 1995;Lanfranco & Eggers, 2012;Guatelli-Steinberg, 2016;Adler et al, 2017). However, evidence for the presence of carious lesions in a variety of non-agricultural hominin groups is growing (e.g., Grine et al, 1990;Trinkaus et al, 2000;Lanfranco & Eggers, 2012;Lacy et al, 2012;Humphrey et al, 2014;Lacy, 2014;Liu et al, 2015;Arnaud et al, 2016;Margvelashvili et al, 2016).…”

Root caries on aParanthropus robustusthird molar from Drimolen

“…The lesion described here adds to the total number, as well as types of caries reported so far in fossil hominins-in this case 12 in P. robustus alone (Clement, 1956;Grine et al, 1990;Robinson, 1952;Towle, 2017). Because caries formation requires fermentable carbohydrates and cariogenic intra-oral bacteria (Clarkson et al, 1987), it is evident that both were present for at least the past 2.0-1.5 million years (Arnaud et al, 2016;Lacy, 2014;Trinkaus et al, 2000;Towle, 2017;Margvelashvili et al, 2016).…”

“…This is the case for many agricultural and huntergatherer diets, with specific cariogenic foods or tough non-cariogenic vegetation/meat (e.g., Novak, 2015;Vodanović et al, 2005;Slaus et al, 2011;Srejic, 2001;Varrela, 1991;Humphrey et al, 2014;Kelley et al, 1991;Lacy, 2014;Larsen et al, 1991). There is growing evidence that this relatively high caries rate is particularly characteristic of the Homo genus (e.g., Arnaud et al, 2016;Lacy, 2014;Lanfranco & Eggers, 2012;Lacy et al, 2012;Liu et al, 2015;Margvelashvili et al, 2016). Given that 12 caries have been described in P. robustus, it is likely that their diet was more similar to earlier Homo than once thought, at least to the extent that both consumed cariogenic foods.…”

“…Caries is often misconceived as a disease unique to recent humans (Guatelli-Steinberg, 2016;Tillier et al, 1995). However, carious lesions are well known in the archaeological record, particularly among agricultural groups, and have been recorded in various fossil hominin and non-human species (e.g., Lacy, 2014;Towle, 2017;Arnaud et al, 2016;Trinkaus et al, 2000;Margvelashvili et al, 2016). In this study we describe a root lesion in a tooth assigned to Paranthropus robustus from Drimolen (Gauteng, South Africa) (Moggi-Cecchi et al, 2010).…”