About

Debbie Guatelli-Steinberg is a Professor in the Department of Anthropology at The Ohio State University. Her research focuses on using teeth to answer questions about life history profiles, growth, and biological relationships in primates and fossil hominins. She emphasizes the importance of teeth as they preserve a record of their growth in hard tissues, reflect the overall growth of the organisms during their lifetime, and are the most often preserved skeletal elements in fossil and archaeological assemblages. Her work has involved non-human primates, Plio-Pleistocene hominins, Neandertals, and modern humans. In addition to her primary research interests, she is also interested in dental sexual dimorphism, fluctuating asymmetry, and dental morphology.

Selected publications

• How wear, age, and sex relate to enamel chipping in Cayo Santiago rhesus macaques (Macaca mulatta)

  PLoS ONE · 2025-12-05 · 1 citations

  articleOpen access1st authorCorresponding

  In living primates, bite forces required to fracture hard-object foods can result in high frequencies of chipped teeth, providing a comparative basis for inferring hard-object feeding in the fossil record. Yet, inferring hard-object feeding from chipping frequencies is complicated by factors such as dental wear, age, and sex that might also affect them. Using dental remains of rhesus macaques (Macaca mulatta) from Cayo Santiago, Puerto Rico, we investigated whether these factors covaried with molar chipping frequencies. We hypothesized that dental wear, because it has a direct relationship to chip formation, would be a stronger predictor of chipping frequencies than age. We also hypothesized that if a sex difference were found, males would have higher frequencies of chipping than females, which is the most common sex difference in chipping found in humans. Samples consisted of 36-38 molars from females and 60-63 molars from males per molar type. Dental wear was measured and chips were identified on consistently oriented occlusal surface photographs. We performed a logistic General Linear Mixed Model (GLMM) of chipping with data on wear and chipping for the six different molar types treated as repeated measures for individuals. The GLMM revealed statistically significant effects for wear and sex, but not for age, on chipping. Our results suggest that wear has a greater effect on chipping frequencies than age, and that sex, at least in this sample, can also affect chipping frequencies. Sex differences in chipping frequencies of the magnitude found here could potentially obscure dietary signals inferred from chipping in studies of fossil primates. These findings suggest that analyzing chipping frequencies with respect to wear and sex could help improve the accuracy of dietary reconstruction of fossil primate diets based on chipping.

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• Dental Fluctuating Asymmetry: Environmental Factors Influencing Cayo Santiago Rhesus Macaque ( <i>Macaca mulatta</i> ) Dental Development

  American Journal of Primatology · 2025-11-01 · 1 citations

  articleOpen access

  ABSTRACT Increased fluctuating asymmetry, or random differences between right and left sides, has been associated with developmental stress or developmental instability. This study examines fluctuating asymmetry (FA) of mesio‐distal and bucco‐lingual dimensions of deciduous maxillary molars (m 1 , m 2 ), and permanent maxillary premolars and molars (P 3 , P 4 , M 1 , M 2 ) of 466 rhesus macaques ( Macaca mulatta ) born between 1950 and 2018 from Cayo Santiago (CS), Puerto Rico. All included individuals were of known age, sex, birth year, and matriline. We assess whether a secular trend occurs in FA over a 68‐year period, sex differences in FA, and whether environmental or management factors in the colony history resulted in decreased FA. Regression of FA on birth year tested for a secular trend in FA. A mixed‐model two‐way analysis of variance was used to test for the influence of food supplementation, tetanus vaccination and hurricane experience during dental development on FA. Differences across matrilines in response to the management or environmental factors were tested by ANOVA. There was no significant secular trend in FA. There was limited reduction of FA with implementation of the high protein diet, and limited support for the decreased FA associated with the implementation of tetanus vaccination. There is also limited difference in dental FA associated with exposure to a hurricane during dental development. Matrilineal differences in FA were observed for several teeth. The free‐ranging environment of Cayo Santiago is a complex environment, with many factors influencing the development of young rhesus macaques. While the introduction of a high protein diet or the implementation of a tetanus vaccination program may have improved individual health overall, there are likely other factors that may cause developmental stress and result in dental FA.

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• CSViewer for Analysts: I. Building an Integrative Database and Knowledge Model for the Cayo Santiago Rhesus Macaque Colony and Its Derived Skeletal Collections

  American Journal of Primatology · 2025-03-01 · 3 citations

  articleOpen access

  The Cayo Santiago rhesus colony and its derived skeletal collections provide abundant data made available since its founding in 1938. A project supported by an NSF collaborative grant has been committed to building a database that integrates the genetic and age-related information of the colony, together with social group interactions and environmental effects, aiming to provide a knowledge model to researchers with insights from this powerful non-human data repository for analyzing human conditions including growth, development, adaption, resilience, aging, and disease in a contextualized manner. This paper introduces CSViewer for Analysts, a computer application that provides user-friendly tools for researchers to access the integrated database and to generate a variety of visuals encompassing matrilineal or patrilineal family lines, social groups, time spans, phenotypic measurements, and photos recently collected through this project. Adopting Java-based technologies and third-party libraries for data analytics and visualization, CSViewer can help its users select meaningful datasets using various criteria, conduct data analytics and visualization tasks, and manage their "project artifacts" (such as selected datasets, models, and charts, etc.). Version 1.0 of the CSViewer app has been tested by collaborators and in a workshop by a limited number of researchers and science educators since 2023. Based on users' feedback, additional features have been implemented in version 1.1.0, and more features are planned for subsequent subversions with bundles for researchers to download and explore.

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• Inter‐Observer Processing and Measurement Error Are Low for <scp>2D</scp> Dental Measurements on Shared <scp>microCT</scp> Scans

  American Journal of Biological Anthropology · 2025-01-31

  articleOpen access

  OBJECTIVES: Sharing micro-computed tomographic (μCT) scans of teeth increases data accessibility and reduces the need for repeated scans of any given specimen. However, the use of the same TIFF stacks or DICOMs by multiple individuals has the potential to introduce new sources of error. Here, we explore whether use of the same μCT scans by different persons produces comparable results. MATERIALS AND METHODS: Worn (N = 11) and unworn (N = 4) Cercocebus atys upper molars (UM1 N = 8, UM2 N = 7) were μCT scanned using a Bruker Skyscan 1172 High Resolution Ex Vivo Scanner at a resolution of 22 μm. Two individuals (K.N.G. and M.C.O.) created a 2D mesial slice for each TIFF stack (tooth). Worn teeth were reconstructed by K.N.G. and M.C.O. Three researchers (M.C.O., K.N.G., and J.R.) measured tooth shape, linear enamel thickness, average enamel thickness, and relative enamel thickness (AET and RET). Inter-observer percent error was calculated for each measurement. Univariate ANOVAs were calculated to evaluate variance due to slice maker, reconstructor, tooth, and measurer when percent error averaged > 5%. RESULTS: For unworn teeth, error was generally low and largely due to the person doing the measurement. For worn teeth, wear reconstructor was a statistically significant source of variation for AET and RET. DISCUSSION: We found that (1) inter-observer error was generally low, (2) linear measurements are prone to error, (3) worn teeth did not present an additional source of error as compared to unworn teeth, and (4) different people can use the same μCT scans to reliably reconstruct, slice, and measure teeth.

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• Inter-rater reliability of stress signatures in exfoliated primary dentition - Improving scientific rigor and reproducibility in histological data collection

  PLoS ONE · 2025-03-19 · 4 citations

  articleOpen accessCorresponding

  Accentuated Lines (ALs) in tooth enamel can reflect metabolic disruptions from physiological or psychological stresses during development. They can therefore serve as a retrospective biomarker of generalized stress exposure in archaeological and clinical research. However, little consensus exists on when ALs are identified and inter-rater reliability is poorly quantified across studies. Here, we sought to address this gap by examining the reliability of accentuated (AL) markings across raters, in terms of both the presence versus absence of ALs and their intensity (HAL= Highly Accentuated, MAL= Mildly Accentuated, RL= Retzius Line). Ratings were made and compared across observers (with different levels of experience) and pairs of raters (who agreed on AL coding through consensus meetings) (N = 15 teeth, eight observers). Results indicated that more experience in AL assessment does not necessarily produce higher reliability between raters. Most disagreements in intensity ratings occurred in categories other than HAL. Furthermore, when AL assessment was performed by pairs of raters, reliability was significantly higher than individual assessments (Gwet's AC1 = 0.28 to 0.56 for line presence assessment; Gwet's AC1 = 0.48 to 0.64 for line intensity assessment). Based on these results, we recommend a workflow called IRRISS (Improving Reliability and Reporting In Scoring of Stress-markers) to increase rigor and reproducibility in histological analysis of dental collections. The introduction of IRRISS is well-timed, given the surge in studies of teeth occurring across anthropological, epidemiological, medical, forensic, and climate research fields.

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• CSViewer for Analysts: II. Analytic Tools and Visualization of Founder Lineages, Social Groups, and Reproduction Dynamics of the Cayo Santiago Rhesus Macaque Colony

  American Journal of Primatology · 2025-06-26 · 2 citations

  articleOpen access

  The Cayo Santiago (CS) rhesus macaque colony has raised a total of over 11,000 animals in a free-ranging setting very close to the natural environment. The well-kept individual and family records, as well as social group management data, have been a valuable source for anthropological research. However, the various sources of data have been stored in separation, and there was no straightforward way for researchers to access them directly. Since 2019, an ongoing effort supported through an NSF collaborative grant has been collecting morphology and imagery data from the CS-derived skeleton collection. One specific aim is to build an integrative database to combine newly collected osteology data (bone measurement) and existing genealogy and demographic information. A second aim is to develop a software application (codenamed as CSViewer for Analysts) to provide user-friendly interfaces for the research community to access and analyze the data. In this paper, we present a set of results generated by using standard data science tools and techniques, which help construct a holistic view of the CS rhesus colony along multiple dimensions. The matrilineal family lineage and pedigree can be visualized using various tree forms, as well as patrilineal lineages traced back to the mid-1970s. Social group evolution charts are generated and add new features to the original records. Reproduction patterns are studied in the context of group interaction and animal transfer logs. Cross-referencing between genealogy and osteology data can also be accomplished. Most of these charts are supported in the CSViewer app with convenient tooltip features to show details as needed. Selection based on attributes like founder line, sex, and birth season can be applied to tailor charts to a research project so that researchers can zoom into a data set that can best support their analytics goals.

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• Uniform, circular, and shallow enamel pitting in hominins: Prevalence, morphological associations, and potential taxonomic significance

  Journal of Human Evolution · 2025-06-05

  articleOpen access

  This study explores a particular form of enamel pitting originally identified in Paranthropus robustus. We call this uniform, circular, and shallow (UCS) pitting to distinguish it from more irregular and nonuniform defects often associated with enamel hypoplasia. We pose the hypothesis that UCS pitting is unique to the genus Paranthropus. We test this by investigating hominin dental remains from the ca. 3.4 Ma to ca. 1.1 Ma fossiliferous sequence at Omo, Ethiopia (n = 76) to look for evidence of UCS pitting in an assemblage that includes at least three hominin genera (Australopithecus, Paranthropus, and Homo). We also examine the correlation between UCS pitting, tooth size, enamel thickness, and cusp proportions in samples from both eastern Africa (Omo) and southern Africa (Drimolen Main Quarry ∼2.04-1.95 Ma, Swartkrans ∼1.9-1.4 Ma, and Kromdraai ∼1.95-1.78 Ma). In the Omo specimens, we found UCS pitting similar to that seen in P. robustus. While we observed this pitting on five of 24 permanent teeth and two deciduous molars from both Paranthropus aethiopicus and Paranthropus boisei, we also identified UCS pitting on five of 13 non-Paranthropus hominin permanent posterior teeth from Member B (∼3.0 Ma). Our correlation studies yielded no association between the presence of UCS pitting and variation in tooth size, enamel thickness, or cusp proportions. The consistent appearance and characteristics of UCS pitting suggest a shared etiology. Our findings also suggest that UCS pitting may result from a genetic effect related to enamel formation, potentially in association with specific environmental or dietary factors.

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• Enamel Prism Angle Variation and Hard‐Object Feeding in Cercopithecoids With Known Diets

  American Journal of Biological Anthropology · 2025-11-01 · 1 citations

  articleOpen accessSenior authorCorresponding

  OBJECTIVES: To examine relationships between enamel prism angles relative to wear surfaces and dietary hardness in three cercopithecoid genera. We hypothesized that the hard-object feeding (durophagous) Cercocebus atys and Lophocebus albigena would have higher prism angles, making their enamel in this region stiffer and stronger in this region, than the soft-object feeding Cercopithecus. We further investigated whether the habitually durophagous Cercocebus atys and the fallback hard-object feeding Lophocebus albigena had similarly high prism angles. MATERIALS AND METHODS: Molars were sectioned using standard protocols and imaged with a Motic BA 310 Microscope with a Moticam camera. ImageJ FIJI was used to measure prism and wear angles. Measurements were made on 13 Cercocebus atys, 13 Lophocebus albigena, and 11 Cercopithecus molars, though sample sizes varied for different comparisons. RESULTS: Repeated measures regressions of upper functional and non-functional cusps were used to test for the effects of tooth, genus, tooth-genus interaction, and wear angle on prism angle. Genus and wear angle were found to be statistically significant predictors. Pairwise comparisons revealed significantly higher prism angles in Cercocebus atys vs. both Lophocebus albigena and Cercopithecus. There was no significant difference between Lophocebus albigena and Cercopithecus in prism angles. DISCUSSION: Our finding that the prism angles of a fallback hard-object feeder (Lophocebus albigena) are more similar to those of a soft-object feeder (Cercopithecus) than to a habitual hard-object feeder (Cercocebus atys) suggests that the correspondence between durophagy and enamel microstructure is not straightforward, complicating our ability to infer durophagy in the fossil record.

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• Revisiting Linear Enamel Hypoplasia in Cayo Santiago Rhesus Macaques (<i>Macaca mulatta</i>): How a Stress Marker Relates to Environment and Maternal Lineage in a Rare Rhesus Colony With Known Life History

  American Journal of Primatology · 2024-11-07 · 5 citations

  articleOpen access1st authorCorresponding

  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 of birth, whether an individual was transferred from the free-ranging colony to the captive facility during probable crown formation periods, and matriline of birth. It was hypothesized that later decades would exhibit higher prevalence than earlier decades as climatic conditions in Puerto Rico worsened over time. Transfer was expected to affect LEH formation because the process of transfer, and subsequent restriction to captivity, is thought to be stressful. Matriline membership was hypothesized to relate to LEH formation because there is some evidence of a genetic influence on susceptibility to form LEH and because offspring of matrilines of different dominance ranks are known to experience different levels of aggression. Lower third premolars with minimal enamel surface wear were scored for LEH using a digital microscope, while a follow-up analysis of the two matrilines with the most extreme differences in LEH frequency was conducted using enamel surface profiles. Results were: (1) individuals born during the 1990s had significantly greater LEH prevalence than those born in the 1960s, (2) transferred individuals exhibited weak evidence of greater LEH prevalence than nontransferred comparison groups, and (3) matrilines did not differ in LEH expression in the initial or follow-up analysis. Although sample sizes were small for some comparisons, these results suggest that not all decades saw an equal prevalence of LEH, that there might be a small effect of transfer from free-ranging to captive conditions on LEH prevalence that is difficult to detect, and that the matriline into which an individual is born is not related to LEH expression.

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• Nutritional supplementation, tooth crown size, and trait expression in individuals from Tezonteopan, Mexico

  PLoS ONE · 2024-06-06 · 5 citations

  articleOpen accessSenior authorCorresponding

  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 = 39) individuals from Tezonteopan, Mexico. We hypothesized that the non-supplemented group would exhibit smaller molar crowns and reduced intercusp spacing. Since intercusp spacing is thought to be more sensitive to epigenetic influences than crown size, we predicted that the supplemented and non-supplemented groups would differ more in the former than the latter. Previous work suggests that molar accessory cusp expression may be elevated under conditions of stress. We therefore expected evidence of greater Carabelli and Cusp 5 trait expression in the non-supplemented group. We further hypothesized that anterior teeth would be affected by nutritional stress during development, with the non-supplemented group having smaller anterior tooth crowns and therefore limited space to form the tuberculum dentale. Finally, we tested whether the presence of molar accessory traits followed predictions of the Patterning Cascade Model of tooth morphogenesis in the entire sample. Our results supported the expectation that cusp spacing would differ more than molar crown size between the two groups. Carabelli trait showed little evidence of frequency differences between groups, but some evidence of greater trait scores in the non-supplemented group. The non-supplemented group also showed evidence of greater Cusp 5 frequency and expression. In the central incisors and canines, there was strong evidence for smaller crown sizes and reduced tuberculum dentale frequency in the non-supplemented group. With both groups pooled together, there was strong evidence of closer mesiodistal distances among principal cusps in molars with accessory cusps, a finding that is consistent with the PCM. Overall, our findings suggest that nutritional stress may affect accessory cusp expression.

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