Debbie Guatelli-Steinberg

The Ohio State University | OSU · Department of Anthropology

Linear enamel hypoplasias (LEHs) are development defects appearing as lines or grooves on enamel surfaces. Forming when physiological stressors disrupt developing teeth, LEHs provide retrospective insight into stress experienced in early development. Here, LEHs in Cayo Santiago rhesus macaques ( Macaca mulatta ) were observed with respect to decade...

Understanding how epigenetic factors impact dental phenotypes can help refine the use of teeth for elucidating biological relationships among human populations. We explored relationships among crown size, principal cusp spacing, and accessory cusp expression in maxillary dental casts of nutritionally supplemented (n = 34) and non-supplemented (n =...

Background Components of diet known as fallback foods are argued to be critical in shaping primate dental anatomy. Such foods of low(er) nutritional quality are often non-preferred, mechanically challenging resources that species resort to during ecological crunch periods. An oft-cited example of the importance of dietary fallbacks in shaping prima...

Objectives This brief communication documents the prevalence of maxillary central incisor talon cusps in Cayo Santiago rhesus monkeys ( Macaca mulatta ) and assesses whether talon cusp presence occurs at equivalent frequencies across matrilines. Materials and Methods The data on cusp presence vs. absence were analyzed by logistic regression in 170...

Physiological stress disrupts normal growth creating visible grooves on the enamel surface (i.e., linear enamel hypoplasia or LEH). Hypoplastic defects often, but not always, co-occur with internal accentuated lines (AL). Monkeys reportedly exhibit fewer enamel defects than hominoids as their presumably faster-growing teeth produce shallower LEH de...

This study investigates aspects of molar form in three African colobine species: Colobus polykomos, Colobus angolensis, and Piliocolobus badius. Our samples of C. polykomos and P. badius are from the Taï Forest, Ivory Coast; our sample of C. angolensis is from Diani, Kenya. To the extent that protective layers surrounding seeds are hard, we predict...

Linear enamel hypoplasias (LEHs) are grooves on tooth crowns that form in response to developmental stressors such as malnutrition and disease. We studied LEH in the anterior teeth of two baboon species (Papio ursinus N=30; P. anubis N=15) hypothesized to be subjected to different stress levels. Using macrophotography, we scored LEH severity as mil...

Objective: This study uses longitudinal data from school children in Dunedin, New Zealand, to evaluate impacts of COVID-19 lockdown measures on changes in body mass (BMI, kg/m2 ). Impacts are assessed using two non-mutually exclusive hypotheses. The "structured days" hypothesis holds that children tend to alter sleep patterns, reduce activity and...

Objectives Developmental defects of tooth enamel are associated with systemic physiological stress and have been linked to seasonal environmental factors such as rainfall, temperature, and fruit availability. Here, we evaluate whether linear enamel hypoplasia and accentuated perikymata occur with any cyclicity on lower canines and then whether cycl...

The hardest component of teeth is enamel, the outer covering of dental crowns, where 96 percent of mature enamel is mineral, composed of hydroxyapatite – a crystalline calcium phosphate. No cells are contained in mature enamel, so that, once it is formed, enamel cannot regrow in the way bone can. This chapter describes the basic biology of enamel g...

Background Evidence of a long-period biological rhythm present in mammalian hard tissue relates to species average body mass. Studies have just begun to investigate the role of this biorhythm in human physiology. Methods The biorhythm is calculated from naturally exfoliated primary molars for 61 adolescents. We determine if the timing relates to l...

Objectives To test the hypothesis that differences in crown structure, enamel growth, and crown geometry in Cercocebus and Lophocebus molars covary with differences in the feeding strategies (habitual vs. fallback durophagy, respectively) of these two genera. Relative to Lophocebus molars, Cercocebus molars are predicted to possess features associa...

Abstract: Stress events such as malnutrition and illness disrupt normal tooth growth creating grooves that are visible on the tooth surface (i.e., linear enamel hypoplasia or LEH). External LEH defects often co-occur with internal manifestations of stress called accentuated lines. However, it is unclear whether the two defect types always co-occur....

Abstract: Linear enamel hypoplasia (LEH) appears as horizontal grooves around the tooth crown, forming in response to stressors like malnutrition and disease. While LEH defects are very common and conspicuous in hominoids, they are less so in monkeys due to their faster tooth growth, creating often overlooked shallower defects. Here, we analyze the...

Objectives: (1) To investigate sex differences in molar wear in known-age Cayo Santiago rhesus macaques (Macaca mulatta) and, (2) To explore sex differences in body weight and molar eruption timing as factors influencing sex differences in molar wear. Materials and methods: Data set I comprises wear scores, ages and body weights of 212 living mo...

Two similarly-sized colobine species living sympatrically in the Ivory Coast's Taï Forest that differ in both diet and oral processing behavior provide an opportunity to explore the strength of associations between feeding behavior and dental wear patterns. Here we test the hypothesis that vigorous processing of tough, hard Pentaclethra macrophylla...

Objective To investigate and describe the variation in enamel daily secretion rates (DSRs) of naturally exfoliated deciduous molars (n = 345) from five modern-day populations (Aotearoa New Zealand, Britain, Canada, France, and Sweden). Design Each tooth was thin sectioned and examined using a high-powered Olympus BX51 microscope and DP25 digital m...

Studies of enamel growth and thickness, whether in paleoanthropology, bioarchaeology, or primatology, require measurements of crown height (CH), cuspal enamel thickness (CET), average (AET), and/or regional enamel thickness (RegAET) on complete, unworn crowns. Yet because fully unworn crowns are uncommon, three methods to bolster sample sizes by re...

Objectives: Linear enamel hypoplasia (LEH) is a common skeletal marker of physiological stress (e.g., malnutrition or illness) that is studied within and across populations, without reference to familial risk. We examine LEH prevalence in a population with known genealogical relationships to determine the potential influence of genetic heritabilit...

ranging from a minor to a major groove in tooth enamel. • Environmental stressors, including lack of food and infectious diseases during critical periods of development are known to induce LEH in human and non-human primates. • Sociobehavioralcorrelates of LEH occurrence have thus far not received adequate attention. To address this gap in our know...

Early life stress disrupts growth and creates horizontal grooves on the tooth surface in humans and other mammals, yet there is no consensus for their quantitative analysis. Linear defects are considered to be nonspecific stress indicators, but evidence suggests that intermittent, severe stressors create deeper defects than chronic, low-level stres...

Primate models are important for understanding human conditions, especially in studies of ageing, pathology, adaptation, and evolution. However, how to integrate data from multiple disciplines and render them compatible with each other for datamining and in-depth study is always challenging. In a long-term project, we have started a collaborative r...

Objectives: Human tooth enamel retains evidence of growth in the form of Retzius lines. The number of daily growth increments between the regularly occurring lines defines their repeat interval, or periodicity. Retzius periodicity is often incorporated into enamel formation times, age-at-death reconstructions, or used to provide a basis from which...

Life on earth is regulated by biological rhythms, some of which oscillate with a circadian, monthly or lunar cycle. Recent research suggests that there is a near weekly biorhythm that may exert an influence on human skeletal growth. Evidence for the timing of this biorhythm is retained in tooth enamel as the periodicity of Retzius lines. Studies re...

Linear enamel hypoplasias (LEH) have been used in physical anthropology as stress indicators. While circumstances such as malnutrition and illness certainly disrupt enamel formation, intrinsic features of enamel growth may affect defect expression as well. Variation in enamel growth factors, particularly lateral enamel formation time and the angle...

Folivorous primates are hypothesized to have relatively larger premolars than frugivores due to the mechanical and energetic challenges of leaf consumption. More specifically, it is reasoned that as folivory increases, so do the mechanical demands of mastication, resulting in more frequent premolar loading. Because interspecific variation in folivo...

Deeper or more 'severe' linear enamel hypoplasia (LEH) defects are hypothesized to reflect more severe stress during development, but it is not yet clear how depth is influenced by intrinsic enamel growth patterns. Recent work documented inter- and intraspecific differences in LEH defect depth in extant great apes, with mountain gorillas having sha...

Linear enamel hypoplasias are developmental defects ranging in appearance from microscopic to macroscopic furrows in enamel that encircle the tooth crown. Environmental stressors, including lack of food and infectious diseases during early periods of development, are known to induce hypoplasias in human and nonhuman primates. Social correlates of h...

Tooth enamel records evidence of dietary behavior in numerous ways, one of which is edge chipping. Prior research has shown that hard-object foods such as seeds and nuts are capable of chipping and/or fracturing enamel. The presence of chipped enamel has been used as evidence of hard-object feeding in paleoanthropological contexts; however, few stu...

Linear enamel hypoplasia (LEH) appears as pronounced horizontal grooves on the outer surface of teeth. LEH defects are understood to represent episodes of nonspecific stress in early life, but little is known about their etiology in nonhuman primates. Researchers have suggested that more severe stressors result in deeper LEH defects, while others a...

Objectives This article presents estimates of narrow‐sense heritability and bivariate genetic correlation for 14 tooth crown morphological variants scored on permanent premolars, first molars, and second molars. The objective is to inform data collection and analytical practices in dental biodistance and to provide insights on the development of mo...

Several human dental traits typical of modern humans appear to be associated with the prolonged period of development that is a key human attribute. Understanding when, and in which early hominins, these dental traits first appeared is thus of strong interest. Using x-ray multiresolution synchrotron phase-contrast microtomography, we quantify denta...

Dental replicas are frequently utilized in paleoanthropological studies of perikymata and enamel hypoplasia. However, fossil teeth are often fragile and worn, causing two problems: (1) the risk of damage by removing enamel fragments when impression‐making material is separated from the fossil tooth surface, and (2) the need to reconstruct worn port...

Dental remains are often found at fossil, archaeological, and forensic sites, as they are small and hard and therefore resist damage. Two of the hard tissues of teeth, enamel and dentine, preserve incremental growth markings that reflect circadian (short‐period) and infradian (long‐period) rhythms. These markings provide paleoanthropologists, bioar...

The Patterning Cascade Model (PCM) explains variation in cusp morphology in mammalian teeth. According to the PCM, cusp development is constrained by the time and space available for morphogenesis and by signaling molecules that create inhibitory zones around enamel knots, thereby preventing the formation of new enamel knots within a circumscribed...

Abstract Objectives: This article presents estimates of narrow-sense heritability and bivariate genetic correlation for a series of morphological crown variants of the anterior dentition. These results provide insight into the value of dental phenotypes as evolutionary proxies, as well as the development of tooth crowns as integrated or modular st...

A new species of Homo, Homo naledi, was described in 2015 based on the hominin skeletal remains from the Dinaledi Chamber of the Rising Star cave system, South Africa. Subsequent craniodental comparative analyses, both phenetic and cladistic, served to support its taxonomic distinctiveness. Here we provide a new quantitative analysis, where up to 7...

Here, we analyze canine histologic sections from four great ape taxa (Gorilla beringei beringei, G. gorilla gorilla, Pan troglodytes, and Pongo sp.; N=41). We measure linear enamel thickness and the angle of internal growth increments as they meet the outer enamel surface (striae angles) in the midcrown region. If variation in canine growth pattern...

Perikymata, incremental growth lines visible on tooth enamel surfaces, differ in their distribution and number among hominin species, although with overlapping patterns. This study asks: (1) How does the distribution of perikymata along the lateral enamel surface of Homo naledi anterior teeth compare to that of other hominins? (2) When both perikym...

Objective: Linear enamel hypoplasia (LEH) is a condition marked by localized reductions in enamel thickness, resulting from growth disruptions during dental development. We use quantitative criteria to characterize the depth of LEH defects and “normal” perikymata in great apes. We test the hypothesis that mountain gorillas have shallow defects comp...

Objectives: This article provides estimates of narrow-sense heritability and genetic pleiotropy for mesiodistal tooth dimensions for a sample of 20th century African American individuals. Results inform biological distance analysis and offer insights into patterns of integration in the human dentition. Materials and methods: Maximum mesiodistal...

Enamel formation front (EFF) angles represent the leading edge of enamel matrix secretion at particular points in time. These angles are influenced by rates of enamel extension (the rates at which tooth crowns grow in height), rates of enamel matrix secretion and the angles that prisms make with the enamel-dentine junction. Previous research sugges...

Evidence of a periodic biorhythm is retained in tooth enamel in the form of Retzius lines. The periodicity of Retzius lines (RP) correlates with body mass and the scheduling of life history events when compared between some mammalian species. The correlation has led to the development of the inter-specific Havers-Halberg oscillation (HHO) hypothesi...

The current study aims to characterise dental scratches found on an East Asian hominin upper left central incisor (I1) and lower left lateral incisor (I2) from the Early Pleistocene (Meipu site, Yunxian County), and infer the preference for handedness of these two individuals by quantifying the orientation of dental scratches. The labial surfaces o...

Studies have suggested that great apes acquire linear enamel hypoplasia (LEH) on a regular, cyclical schedule corresponding to seasonal environmental patterns. However, these studies have been limited to averaging the amount of time between defects rather than considering the sequence of defects across an entire tooth. In addition, the possibility...

The causes of Neandertal anterior tooth wear patterns, including labial rounding, labial scratches, and differential anterior-posterior wear, have been debated for decades. The most common explanation is the “stuff-and-cut” hypothesis, which describes Neandertals clamping down on a piece of meat and slicing a portion close to their lips. “Stuff-and...

Objectives: To update histological data on crown initiation and completion ages in southern Africans. To evaluate implications of these data for studies that: (a) rely on these data to time linear enamel hypoplasias (LEHs), or, (b) use these data for comparison to fossil hominins. Materials and methods: Initiation ages were calculated on 67 hist...

The Havers-Halberg Oscillation (HHO) hypothesis links evidence for the timing of a biorhythm retained in permanent tooth enamel (Retzius periodicity) to adult body mass and life history traits across mammals. Potentially, these links provide a way to access life history of fossil species from teeth. Recently we assessed intra-specific predictions o...

Over millions of years in the fossil record, hominin teeth preserve a high-fidelity record of their own growth, development, wear, chemistry and pathology. They yield insights into human evolution that are difficult, if not impossible, to achieve through other sources of fossil or archaeological data. Integrating dental findings with current debate...

Across mammalian species, the periodicity with which enamel layers form (Retzius periodicity) in permanent teeth corresponds with average body mass and the pace of life history. According to the Havers-Halberg Oscillation hypothesis (HHO), Retzius periodicity (RP) is a manifestation of a biorhythm that is also expressed in lamellar bone. Potentiall...

Developmental defects of enamel, especially enamel hypoplasias and accentuated striae, can provide biological anthropologists with a detailed, retrospective record of the physiological stress experience during childhood. These non-specific indicators of stress provide insights relevant to diverse fields in biological (and dental) anthropology. This...

The means by which the size, shape, and number of teeth in mammals are determined in development has long been of interest to geneticists, paleontologists, and anthropologists. In the past two decades, great strides have been made to understand the action of genes in developing teeth to bring about the variation in tooth shape, size, and number tha...

The analysis of dental remains, which outlast most other tissues in the human body, provides insight into past diet, activity patterns and ancestry. The remains from Bab edh-Dhra' represent the only skeletal sample available to as-sess the impact of agricultural intensification in the Early Bronze Age of the southern Levant (ca. 3500–2000 BCE). Thi...

Dental pathologies and enamel defects in East Asian hominins have rarely been reported. Here, we systematically document and describe a suite of enamel defects in the Xujiayao juvenile maxilla, an East Asian hominin from the early Late Pleistocene that may represent an unknown hominin lineage. In addition, we determine the chronology of growth disr...

Previous studies suggest that palate shape is a useful indicator of biological ancestry in human remains. This study evaluates interobserver error in ancestry estimation using palate shape and explores palate shape variation in Gullah (descendants of West Africans) and Seminole (Indigenous American) population samples using geometric morphometric a...

Objectives This study investigates where the Xujiayao juvenile (I1 and C1) fits into the array of perikymata distribution patterns found within the genus Homo.Materials and Methods In addition to the I1 and the C1 of the Xujiayao juvenile, this study includes samples of early Homo (H. rudolfensis and H. erectus), Neandertals, early modern humans (Q...

Pan paniscus and Pan troglodytes diverged 2-2.5mya; behavioral, morphological, and life history similarities and differences exist between the species. The species appear to have similar dental development in tooth crown and root formation timing. However, based on a single Pan paniscus upper incisor, it has been suggested that the species’ distrib...

This study investigates whether variants in dental morphology and nuclear DNA provide similar patterns of intergroup affinity among regional populations using biological distance (biodistance) estimates. Many biodistance studies of archaeological populations use skeletal variants in lieu of ancient DNA, based on the widely accepted assumption of a...

During childhood, systemic physiological stresses such as illness, disease, and malnutrition can disrupt the growth of dental enamel. These disruptions are often recorded in the form of linear enamel hypoplasia (LEH). Many researchers have analyzed the frequency and timing of LEH formation in Neanderthal populations as they relate to ideas about Ne...

This study reconstructs linear enamel hypoplasia (LEH) prevalence and stress episode duration among Jomon period foragers from Hokkaido, Japan (HKJ). Results are compared to Jomon period samples from coastal Honshu, Japan (HSJ) and Tigara Inupiat from Point Hope, Alaska (PHT) to provide a more comprehensive perspective on the manifestation of stres...

The Sunghir 2 and 3 late juvenile to early adolescent immature skeletons, from the Mid Upper Paleolithic (Eastern Gravettian) of northern Russia, exhibit several episodes of dental enamel hypoplasias. Those of the older male Sunghir 2 relate principally to a stress episode in the third year post-natal, although subse-quent minor stress episodes may...

Here we describe dental remains from a Neanderthal fossil assemblage from Moula-Guercy, France. Our report demonstrates that the Moula-Guercy hominid remains contribute important morphological, developmental, and behavioral data to understanding Neanderthal evolutionary history. We include gross comparative morphological descriptions and enamel sur...

To characterize further the Australopithecus sediba hypodigm, we describe 22 dental traits in specimens MH1 and MH2. Like other skeletal elements, the teeth present a mosaic of primitive and derived features. The new nonmetric data are then qualitatively and phenetically compared with those in eight other African hominin samples, before cladistic a...

The patterning cascade model of tooth morphogenesis has emerged as a useful tool in explaining how tooth shape develops and how tooth evolution may occur. Enamel knots, specialized areas of dental epithelium where cusps initiate, act as signaling centers that direct the growth of surrounding tissues. For a new cusp to form, an enamel knot must form...

Researchers have long had an interest in dental morphology as a genetic proxy to reconstruct population history. Much interest was fostered by the use of standard plaques and associated descriptions that comprise the Arizona State University Dental Anthropology System, developed by Christy G. Turner, II and students. This system has served as the f...

Previous studies have suggested that Neandertals experienced greater physiological stress and/or were less capable of mitigating stress than most prehistoric modern human populations. The current study compares estimates of dental fluctuating asymmetry (DFA) for prehistoric Inupiat from Point Hope Alaska, the Late Archaic, and Protohistoric periods...

After 1–2 weeks of birth, a newborn experiences a surge in serum concentrations of gonadotropins and sex steroids. The gonadotropins follicle stimulating hormone (FSH) and luteinizing hormone (LH) attain peak levels at 2–3 months of postnatal life, stimulating an elevated output of sex steroid hormones (testosterone, estradiol, and inhibin B) from...

We describe and analyze a Neandertal postcranial skeleton and dentition, which together show unambiguous signs of right-handedness. Asymmetries between the left and right upper arm in Regourdou 1 were identified nearly 20 years ago, then confirmed by more detailed analyses of the inner bone structure for the clavicle, humerus, radius and ulna. The...