Mark Teaford
Touro University California, Basic Science, Faculty Member
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Recent work with modern mammalian teeth has shown that, during an animal's lifetime, microscopic wear patterns are generally laid down in a regular fashion at specific locations on the teeth. These regularities make it possible to... more
Recent work with modern mammalian teeth has shown that, during an animal's lifetime, microscopic wear patterns are generally laid down in a regular fashion at specific locations on the teeth. These regularities make it possible to distinguish real dental microwear (resulting from behaviors during life) from artifacts of preservation and preparation (postmortem wear) on fossil teeth. The size, shape, location, and orientation of microscopic wear features can all aid in making such distinctions. Several types of postmortem wear are identifiable on fossil teeth. Since some of these effects are intimately tied to the taphonomic history of the fossil, some postmortem wear will vary significantly within and between paleontological sites. Moreover, certain forms of postmortem wear will undoubtedly pose problems for microwear interpretations involving fragments of teeth. Still, it is usually possible to distinguish postmortem wear from real dental microwear in complete specimens. If the...
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A diverse assemblage of large mammals is spatially and stratigraphically associated with Ardipithecus ramidus at Aramis. The most common species are tragelaphine antelope and colobine monkeys. Analyses of their postcranial remains situate... more
A diverse assemblage of large mammals is spatially and stratigraphically associated with Ardipithecus ramidus at Aramis. The most common species are tragelaphine antelope and colobine monkeys. Analyses of their postcranial remains situate them in a closed habitat. Assessment of dental mesowear, microwear, and stable isotopes from these and a wider range of abundant associated larger mammals indicates that the local habitat at Aramis was predominantly woodland. The Ar. ramidus enamel isotope values indicate a minimal C 4 vegetation component in its diet (plants using the C 4 photosynthetic pathway), which is consistent with predominantly forest/woodland feeding. Although the Early Pliocene Afar included a range of environments, and the local environment at Aramis and its vicinity ranged from forests to wooded grasslands, the integration of available physical and biological evidence establishes Ar. ramidus as a denizen of the closed habitats along this continuum.
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There is a degree of correlation between dietary habits and dental microwear in extant primates, and this has enabled inferences to be made about prehistoric diets. Several techniques have been used to quantify microwear, but the... more
There is a degree of correlation between dietary habits and dental microwear in extant primates, and this has enabled inferences to be made about prehistoric diets. Several techniques have been used to quantify microwear, but the comparability of results derived from each has not been demonstrated. Moreover, neither intra‐ nor interobserver error rates in microwear quantification have been documented to date. We here assess intra‐ and interobserver error using Microware 4.0, and evaluate intertechnique comparability using the three methods that have been most widely employed in the field. This study documents an overall intraobserver error rate of about 7%, and an overall interobserver error rate of some 9%. Both intra‐and interobserver error appears to be influenced substantially by the nature of the micrograph being measured. In no instance did the results obtained by different observers using Microware 4.0 differ significantly, and there was a reasonable degree of interobserver c...
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Over the past decade, discussions of the evolution of the earliest human ancestors have focused on the locomotion of the australopithecines. Recent discoveries in a broad range of disciplines have raised important questions about the... more
Over the past decade, discussions of the evolution of the earliest human ancestors have focused on the locomotion of the australopithecines. Recent discoveries in a broad range of disciplines have raised important questions about the influence of ecological factors in early human evolution. Here we trace the cranial and dental traits of the early australopithecines through time, to show that between 4.4 million and 2.3 million years ago, the dietary capabilities of the earliest hominids changed dramatically, leaving them well suited for life in a variety of habitats and able to cope with significant changes in resource availability associated with long-term and short-term climatic fluctuations.
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Many researchers have suggested that Australopithecus anamensis and Australopithecus afarensis were among the earliest hominins to have diets that included hard, brittle items. Here we examine dental microwear textures of these hominins... more
Many researchers have suggested that Australopithecus anamensis and Australopithecus afarensis were among the earliest hominins to have diets that included hard, brittle items. Here we examine dental microwear textures of these hominins for evidence of this. The molars of three Au. anamensis and 19 Au. afarensis specimens examined preserve unobscured antemortem microwear. Microwear textures of these individuals closely resemble those of Paranthropus boisei , having lower complexity values than Australopithecus africanus and especially Paranthropus robustus . The microwear texture complexity values for Au. anamensis and Au. afarensis are similar to those of the grass-eating Theropithecus gelada and folivorous Alouatta palliata and Trachypithecus cristatus . This implies that these Au. anamensis and Au. afarensis individuals did not have diets dominated by hard, brittle foods shortly before their deaths. On the other hand, microwear texture anisotropy values for these taxa are lower o...
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Reconstructing the diets of extinct hominins is essential to understanding the paleobiology and evolutionary history of our lineage. Dental microwear, the study of microscopic tooth-wear resulting from use, provides direct evidence of... more
Reconstructing the diets of extinct hominins is essential to understanding the paleobiology and evolutionary history of our lineage. Dental microwear, the study of microscopic tooth-wear resulting from use, provides direct evidence of what an individual ate in the past. Unfortunately, established methods of studying microwear are plagued with low repeatability and high observer error. Here we apply an objective, repeatable approach for studying three-dimensional microwear surface texture to extinct South African hominins. Scanning confocal microscopy together with scale-sensitive fractal analysis are used to characterize the complexity and anisotropy of microwear. Results for living primates show that this approach can distinguish among diets characterized by different fracture properties. When applied to hominins, microwear texture analysis indicates that Australopithecus africanus microwear is more anisotropic, but also more variable in anisotropy than Paranthropus robustus. This ...
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New World monkeys display a wide range of masticatory apparatus morphologies related to their diverse diets and feeding strategies. While primatologists have completed many studies of the platyrrhine masticatory apparatus, particularly... more
New World monkeys display a wide range of masticatory apparatus morphologies related to their diverse diets and feeding strategies. While primatologists have completed many studies of the platyrrhine masticatory apparatus, particularly morphometric analyses, we collectively acknowledge key shortcomings in our understanding of the function and evolution of the platyrrhine feeding apparatus. Our goal in this contribution is to review several recent, and in most cases ongoing, efforts to address some of the deficits in our knowledge of how the platyrrhine skull is loaded during feeding. We specifically consider three broad research areas: (1) in vivo physiological studies documenting mandibular bone strains during feeding, (2) metric analyses assessing musculoskeletal functional morphology and performance, as well as (3) the initiation of a physiological ecology of feeding that measures in vivo masticatory mechanics in a natural environment. We draw several conclusions from these brief...
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ABSTRACTInference of feeding adaptation in extinct species is challenging, and reconstructions of the paleobiology of our ancestors have utilized an array of analytical approaches. Comparative anatomy and finite element analysis assist in... more
ABSTRACTInference of feeding adaptation in extinct species is challenging, and reconstructions of the paleobiology of our ancestors have utilized an array of analytical approaches. Comparative anatomy and finite element analysis assist in bracketing the range of capabilities in taxa, while microwear and isotopic analyses give glimpses of individual behavior in the past. These myriad approaches have limitations, but each contributes incrementally toward the recognition of adaptation in the hominin fossil record. Microwear and stable isotope analysis together suggest that australopiths are not united by a single, increasingly specialized dietary adaptation. Their traditional (i.e., morphological) characterization as “nutcrackers” may only apply to a single taxon, Paranthropus robustus. These inferences can be rejected if interpretation of microwear and isotopic data can be shown to be misguided or altogether erroneous. Alternatively, if these sources of inference are valid, it merely ...
Research Interests: Evolutionary Biology, Archaeology, Anthropology, Biology, Diet, and 15 moreInference, Dental microwear, Finite Element, Medicine, American Journal of Physical Anthropology, Finite Element Analysis, Australopithecus, Carbon Isotopes, Animals, Jaw, Biological evolution, Feeding Behavior, Hominidae, Dental Enamel, and Biomechanical Phenomena
Research Interests: Evolutionary Biology, Archaeology, Anthropology, Computed Tomography, Biology, and 15 moreDiet, Medicine, Animals, Mandible, American, Animal Experimentation, High Resolution, Cross Section, Mastication, Bending Strength, Bone Strength, Control Group, Biomechanical Phenomena, Molar, and Dental Impression Technique
San Luis de Apalachee, one of a chain of Roman Catholic missions established in Spanish Florida (modern states of Georgia and Florida) in the sixteenth and seventeenth centuries, was the principal center of missionization of native... more
San Luis de Apalachee, one of a chain of Roman Catholic missions established in Spanish Florida (modern states of Georgia and Florida) in the sixteenth and seventeenth centuries, was the principal center of missionization of native populations in the Florida panhandle. Paleoethnobotanical remains yield evidence of production of various kinds of crops at the site, typical of nearly all mission period sites in the area. Stable isotope (carbon and nitrogen) analysis and dental caries evidence suggest that maize was not as important in the diet at San Luis as in other contemporary settings in the region. Ethnohistorical research indicates a heavier reliance on meat consumption compared to other mission settings. This study examines dental microwear of occlusal surfaces of maxillary molars from San Luis and five other Native American mission period sites in Spanish Florida. Epoxy casts of molar crushing facets were photographed under 500× magnification, using a scanning electron microsco...
Research Interests: Evolutionary Biology, Geography, Archaeology, Anthropology, Diet, and 15 moreNative American, Medicine, American Journal of Physical Anthropology, Humans, Maize, Stable Isotope, Dental Caries, Florida, Nitrogen, Multiple comparisons, Analysis of Variance, North American Indians, Electron Microscope, Religious missions, and Molar
Paleoprimatologists depend on relationships between form and function of teeth to reconstruct the diets of fossil species. Most of this work has been limited to studies of unworn teeth. A new approach, dental topographic analysis, allows... more
Paleoprimatologists depend on relationships between form and function of teeth to reconstruct the diets of fossil species. Most of this work has been limited to studies of unworn teeth. A new approach, dental topographic analysis, allows the characterization and comparison of worn primate teeth. Variably worn museum specimens have been used to construct species‐specific wear sequences so that measurements can be compared by wear stage among taxa with known differences in diet. This assumes that individuals in a species tend to wear their molar teeth in similar ways, a supposition that has yet to be tested. Here we evaluate this assumption with a longitudinal study of changes in tooth form over time in primates. Fourteen individual mantled howling monkeys (Alouatta palliata) were captured and then recaptured after 2, 4, and 7 years when possible at Hacienda La Pacifica in Costa Rica between 1989–1999. Dental impressions were taken each time, and molar casts were produced and analyzed...
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Dental microwear researchers consider exogenous grit or dust to be an important cause of microscopic wear on primate teeth. No study to date has examined the accumulation of such abrasives on foods eaten by primates in the forest. This... more
Dental microwear researchers consider exogenous grit or dust to be an important cause of microscopic wear on primate teeth. No study to date has examined the accumulation of such abrasives on foods eaten by primates in the forest. This investigation introduces a method to collect dust at various heights in the canopy. Results from dust collection studies conducted at the primate research stations at Ketambe in Indonesia, and Hacienda La Pacifica in Costa Rica indicate that 1) grit collects throughout the canopy in both open country and tropical rain forest environments; and 2) the sizes and concentrations of dust particles accumulated over a fixed period of time differ depending on site location and season of investigation. These results may hold important implications for the interpretation of microwear on primate teeth. © 1995 Wiley‐Liss, Inc.
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One problem with dental microwear analyses of museum material is that investigators can never be sure of the diets of the animals in question. An obvious solution to this problem is to work with live animals. Recent work with laboratory... more
One problem with dental microwear analyses of museum material is that investigators can never be sure of the diets of the animals in question. An obvious solution to this problem is to work with live animals. Recent work with laboratory primates has shown that high resolution dental impressions can be obtained from live animals. The purpose of this study was to use similar methods to begin to document rates and patterns of dental microwear for primates in the wild.Thirty‐three Alouatta palliata were captured during the wet season at Hacienda La Pacifica near Canas, Costa Rica. Dental impressions were taken and epoxy casts of the teeth were prepared using the methods of Teaford and Oyen (1989a). Scanning electron micrographs were taken of the left mandibular second molars at magnifications of 200× and 500×. Lower magnification images were used to calculate rates of wear, and higher magnification images were used to measure the size and shape of microwear features.Results indicate tha...
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Dental microwear has long been used as evidence concerning the diets of extinct species. Here, we present a comparative baseline series of dental microwear textures for a sample of 21 anthropoid primate species displaying interspecific... more
Dental microwear has long been used as evidence concerning the diets of extinct species. Here, we present a comparative baseline series of dental microwear textures for a sample of 21 anthropoid primate species displaying interspecific and intraspecific dietary variability. Four dental microwear texture variables (complexity, anisotropy, textural fill volume, and heterogeneity) were computed based on scale‐sensitive fractal analysis and high‐resolution three‐dimensional renderings of microwear surfaces collected using a white‐light confocal profiler. The purpose of this analysis was to assess the extent to which these variables reflect variation in diet. Significant contrasts between species with diets known to include foods with differing material properties are clearly evident for all four microwear texture variables. In particular, species that consume more tough foods, such as leaves, tended to have high levels of anisotropy and low texture complexity. The converse was true for ...
Research Interests: Evolutionary Biology, Archaeology, Anthropology, Dental Anthropology, Biology, and 13 moreDiet, Physical Anthropology, Medicine, Anisotropy, American Journal of Physical Anthropology, Tooth wear, Animals, Primate, Analysis of Variance, Interspecific competition, Intraspecific Competition, Food Mechanical Properties, and Haplorhini
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Several recent studies have stressed the role of dietary change in the origin and early evolution of our genus in Africa. Resulting models have been based on nutrition research and analogy to living peoples and nonhuman primates or on... more
Several recent studies have stressed the role of dietary change in the origin and early evolution of our genus in Africa. Resulting models have been based on nutrition research and analogy to living peoples and nonhuman primates or on archeological and paleoenvironmental evidence. Here we evaluate these models in the context of the hominin fossil record. Inference of diet from fossils is hampered by small samples, unclear form-function relationships, taphonomic factors, and interactions between cultural and natural selection. Nevertheless, craniodental remains of Homo habilis, H. rudolfensis, and H. erectus offer some clues. For example, there appears to be no simple transition from an australopith to a Homo grade of dietary adaptation, or from closed forest plant diets to reliance on more open-country plants or animals. Early Homo species more likely had adaptations for flexible, versatile subsistence strategies that would have served them well in the variable paleoenvironments of ...