M. Teaford - Academia.edu (original) (raw)
Papers by M. Teaford
Journal of Human Evolution, 2004
Journal of Human Evolution, 2006
Conventional wisdom ties the origin and early evolution of the genus Homo to environmental change... more Conventional wisdom ties the origin and early evolution of the genus Homo to environmental changes that occurred near the end of the Pliocene. The basic idea is that changing habitats led to new diets emphasizing savanna resources, such as herd mammals or underground storage organs. Fossil teeth provide the most direct evidence available for evaluating this theory. In this paper, we present a comprehensive study of dental microwear in Plio-Pleistocene Homo from Africa. We examined all available cheek teeth from Ethiopia, Kenya, Tanzania, Malawi, and South Africa and found 18 that preserved antemortem microwear. Microwear features were measured and compared for these specimens and a baseline series of five extant primate species (Cebus apella, Gorilla gorilla, Lophocebus albigena, Pan troglodytes, and Papio ursinus) and two protohistoric human foraging groups (Aleut and Arikara) with documented differences in diet and subsistence strategies. Results confirmed that dental microwear reflects diet, such that hard-object specialists tend to have more large microwear pits, whereas tough food eaters usually have more striations and smaller microwear features. Early Homo specimens clustered with baseline groups that do not prefer fracture resistant foods. Still, Homo erectus and individuals from Swartkrans Member 1 had more small pits than Homo habilis and specimens from Sterkfontein Member 5C. These results suggest that none of the early Homo groups specialized on very hard or tough foods, but that H. erectus and Swartkrans Member 1 individuals ate, at least occasionally, more brittle or tough items than other fossil hominins studied.
Vertebrate Paleobiology and Paleoanthropology, 2007
Fifty years ago, investigators realized they could gain insights into jaw movement and tooth-use ... more Fifty years ago, investigators realized they could gain insights into jaw movement and tooth-use through lightmicroscope analyses of wear patterns on teeth. Since then, numerous analyses of modern and fossil material have yielded insights into the evolution of tooth use and diet in a wide variety of animals. However, analyses of fossils and archeological material are ultimately dependent on data from three sources, museum samples of modern animals, living animals (in the wild or in the lab), and in vitro studies of microwear formation. These analyses are not without their problems. Thus, we are only beginning to get a clearer picture of the dental microwear of the early hominins. Initial work suggested qualitative differences in dental microwear between early hominids, but it wasn't until Grine's analyses of the South African australopithecines that we began to see quantitative, statistical evidence of such differences. Recent analyses have (1) reaffirmed earlier suggestions that Australopithecus afarensis shows microwear patterns indistinguishable from those of the modern gorilla, and (2) shown that the earliest members of our genus may also be distinguishable from each other on the basis of their molar microwear patterns. While this work hints at the possibilities of moving beyond standard evolutionary-morphological inferences, into inferences of actual differences in tooth use, we still know far too little about the causes of specific microwear patterns, and we know surprisingly little about variations in dental microwear patterns (e.g., between sexes, populations, and species). In the face of such challenges, SEM-analyses may be reaching the limits of their usefulness. Thus, two methods are beginning to catch attention as possible "next steps" in the evolution of dental microwear analyses. One technique involves a return to lower magnification analyses, using qualitative assessments of microwear patterns viewed under a light microscope. The advantages of these analyses are that they are cheap and fast, and may easily distinguish animals with extremely different diets. The disadvantages are that they are still subjective and may not be able to detect subtle dietary differences or artifacts on tooth surfaces. Another technique involves the use of scale-sensitive fractal analyses of data from a confocal microscope. Advantages include the ability to quickly and objectively characterize wear surfaces in 3D over entire wear facets. The main disadvantage lies in the newness of the technique and challenges imposed by developing such cutting edge technology. With the development of new approaches, we may be able to take dental microwear analyses to a new level of inference.
Pour La Science, 1989
Res. d'A. Soixante ans apres sa decouverte, Proconsul semble le dernier ancetre commun aux Gr... more Res. d'A. Soixante ans apres sa decouverte, Proconsul semble le dernier ancetre commun aux Grands Singes et a l'Homme
Scientific American, 1989
Sixty years after its discovery, Proconsul is now known to be the last common ancestor of great a... more Sixty years after its discovery, Proconsul is now known to be the last common ancestor of great apes and human beings rather than an extinct ancestor of the chimpanzee and the gorilla
Journal of Zoology, 1990
With 3 plates and 4 figures in the text) Patterns of dental microwear provide some of the best in... more With 3 plates and 4 figures in the text) Patterns of dental microwear provide some of the best indirect evidence of tooth use and diet in living and extinct species, and thus can supplement inferences based on gross morphology. In this paper, dental microwear features are examined in the extinct sabretooth cat Smilodon fatalis and among eight species of extant large carnivores, including felids, canids, hyaenids and a mustelid. Although all the living species are primarily carnivorous, some differ in the relative quantities of large bones consumed; hyaenas are the most frequent bone-crushers and cheetahs the least. Because bone is harder than meat, interspecific differences in bone consumption are expected to be reflected by differences in microwear pattern. Scanning electron micrographs of the wear facet of the lower first molar (carnassial) were used to estimate the average density, size, shape and orientation of microwear features for each species. Results indicate that dietary differences are highlighted when features shorter than 30 pm in length are excluded from the analysis. When this is done, hyaenas are distinguished from other species by a combination of relatively few long features and a high proportion of pits to scratches. By contrast, the cheetah is characterized by a predominance of narrow features, relatively few of which are pits. Species of intermediate diet, such as the wolf, leopard, wild dog and wolverine, tend to be intermediate in pit density and feature shape. Comparisons of the carnivore microwear data with that published for primates reveal that the eight carnivores are most similar to frugivorous primates that specialize on relatively hard fruits. In addition, the orientation of microwear features is significantly more variable in carnivores than in the only comparably studied primate, the chimpanzee. This suggests that many of the microwear features on the carnassial are produced by food moving in directions other than occlusal pathways. The pattern of microwear features in the sabretooth cat is distinct from all of the sampled extant carnivores. Smilodon has relatively narrow, long features and an extremely low pit frequency. Thus Smilodon probably consumed less bone than does the cheetah and may have left behind significant amounts of bone and meat for scavengers. The sabretooth cat may have avoided bone in order to protect its long canines from breakage.
The Journal of Prosthetic Dentistry, 1988
Journal of Human Evolution, 1988
In 1984 a joint National Museums of Kenya-Johns Hopkins University party began studies on the iso... more In 1984 a joint National Museums of Kenya-Johns Hopkins University party began studies on the isolated and unusual site known as R114 or "Whitworth's Pot-hole" at the northwest extremity of Rusinga Island, western Kenya, from which the partial skeleton of Proconsul africanus, KNM-RU 2036 was recovered in 195 1 (Napier & Davis, 1959; Walker & Pickford, 1983). We have published a brief note on the geology and taphonomy of the site and the recovery of additional bones from the skeleton (Walker et al., 1986). Here, we give a preliminary account of remarkably complete remains from several Proconsul individuals found together at site R5 on Kaswanga Point, 3 km east of R114.
Journal of Human Evolution, 1988
A hominoid proximal humerus from the Early Miocene of Rusinga Island, Kenya Recently, an isolated... more A hominoid proximal humerus from the Early Miocene of Rusinga Island, Kenya Recently, an isolated proximal humerus of an early Miocene hominoid was discovered at Rusinga Island, Kenya. The precise tasonomic allocation of this specimen is currently problematic. but the fossil almost certainly belongs to either Dendropithecus macinne~i or Proconsul aj%canus. The humeral head 1s expanded above the greater tuberosity in the new fossil suggesting that this early Miocene hominoid possessed a relatively mobile shoulder joint for climbing as well as for postural and feeding activities, and that rapid protraction at the shoulder joint was not important. This proximal humeral morphology contrasts with that of Aegyptopithecus, but is quite similar to that of Pliopithecus. Among extant primates, a similar proximal humeral morphology occurs in several platyrrhines such as Alouatta, but living apes share several apparently derived features of the proximal humerus which are lacking in the Rusinga Island specimen.
Journal of Human Evolution, 1991
Journal of Human Evolution, 1991
Journal of Human Evolution, 1989
The criteria traditionally used to distinguish between species of Proconsul have been largely siz... more The criteria traditionally used to distinguish between species of Proconsul have been largely size-related and based primarily on the dentition. Wt. present here new estimates of body mass for seven Proconml from earl\ Miocene (17.8 mybp) sites on Rusinga and Mfangano Islands. Kenya, derived from cross-sectional diaphyseal and articular dimensions of the femur, structural features that bear a close functional relationship to body mass in living species. The fossil specimens cluster into two major groups: one at just over 9 kg (including the well-known KNM-RU 2036), and the other between about 26 and 38 kg. Since a 3: 1 to 4: I body mass ratio between males and females of the same species is unknown among living primates or indeed land mammals, it seems most probable, contrary to some recent hypotheses, that at least two species ofProcomu1 are represented at these sites-the larger P. nyanza~ and the smaller a new species formerly identified as P. africanus. The P. nyanzne specimens can be further divided into subgroups ofabout 35-38 kg and 2628 kg, which may represent males and females of this species. In terms of size and general proportions, the f. nyanrae femora are most similar to those of pygmy chimpanzees, while the smaller Procoltstil femora are similar to those ofsome living cercopithecines. The P. nynn~ne femora also show evidence of a relatively mobile (ape-like) hip joint. However, in certain respects the general hindlimh bone proportions of the largest living cercopithecines and smallest great apes arc similar, overlapping within the body size range ofP. nyanrae, i.e., near 30 kg. The relatively shorter and thus more robust appearing femora of the larger living African apes may be a result of mechanical constraints associated with climbing in an anthropoid with a body mass significantly above this size range. which nevertheless remains the most commonly used characteristic for estimating body 0047-2484/89/0605
Journal of Dental Research, 1991
Human tooth wear occurs so slowly that traditionally it has needed months or years to be measurab... more Human tooth wear occurs so slowly that traditionally it has needed months or years to be measurable. This study showed that microscopic changes in wear patterns on human teeth could be detected in a matter of days and could be used as indicators of rates of wear. Thus, daily or weekly changes in rates of wear can be documented for specific locations on teeth. For instance, through this new approach, rates of wear of human teeth were shown to be significantly slower than rates of wear of the teeth of laboratory monkeys raised on hard or soft diets. Similar techniques may ultimately be used to monitor subtle changes in tooth use-including those associated with growth and development and those occurring in response to various dental clinical procedures.
Folia Primatologica, 1995
Leaves of two plant species eaten by Macaca fascicularis in Bukit Timah Nature Reserve, Singapore... more Leaves of two plant species eaten by Macaca fascicularis in Bukit Timah Nature Reserve, Singapore, were collected and colour-tested. Leaves matching those eaten by M. fascicularis were examined by energy-dispersive X-ray micro-analysis. The leaves of Streblus elongatus (Moraceae) and Gluta wallichii (Anacardiaceae), together forming 19.6% of the leaf diet of the macaques, contained silica. In G. wallichii, this is in the base of hairs that project from the underside of the leaf, whereas S. elongatus leaves have short sharp siliceous trichomes which are densely packed on the undersurface of leaf veins. We predict from an indentation analysis that chewing on the latter species could cause dental microwear at low occlusal forces. The leaves are reportedly common in the diet of three other primate species in peninsular Malaysia and the finding could have general significance for studies of dental wear.
Folia Primatologica, 1989
Tooth microwear studies have been carried out for several reasons in the last decade. Most effort... more Tooth microwear studies have been carried out for several reasons in the last decade. Most effort has been put into categorizing wear types that reflect dietary preferences in order to reconstruct the diet of extinct species. Several studies have shown that, for primates, carnivores and ruminants, it is possible to differentiate statistically the microwear associated with the major dietary adaptations in the group. It has further been found that more subtle dietary changes, such as seasonal ones, can be picked up if the sampling is good enough. It is important to recognize that, although it may be a valuable and legitimate concern to study the specific causes of different microwear patterns, that information is not essential for dietary reconstruction, if different microwear states can be shown empirically to correspond to different dietary regimes. Image enhancement and optical diffraction methods offer hope of automated scanning of large samples. This will be a major benefit as th...
American Journal of Physical Anthropology, 1984
Studies of dental microwear have been used to relate tooth form to function in a variety of recen... more Studies of dental microwear have been used to relate tooth form to function in a variety of recent and extinct mammals. Probably the most important aspect of microwear analysis is the possibility of using it to deduce the diet of extinct animals. Such deductions must be based on comparative studies of modern species with known diets, but to date, only qualitative studies have been attempted and all have been based on small samples. Here we report quantitative differences in dental microwear between primate species that are known to have different diets. Occlusal facets with different functions have previously been shown to exhibit different microwear patterns. However, the differences between facets of one species are shown to be far less than those between homologous facets of different species. Study of seven species of extant primates shows that enamel microwear can be used to distinguish between those with a mainly frugivorous diet and those with a mainly folivorous one. Microwear can also distinguish hard-object feeders from soft-fruit eaters. The microwear of Miocene Sivapithe cus indicus cannot be distinguished statistically from that of the chimpanzee, but it is different from that of the other species. On this evidence S. indicus was not a hard-object feeder and the adaptive significance of its thick molar enamel is a t present unknown.
American Journal of Physical Anthropology, 1989
Given the potential usefulness of dental microwear analyses in interpretations of archaeological ... more Given the potential usefulness of dental microwear analyses in interpretations of archaeological and paleontological material, it is surprising how little we know about changes in individual microwear features through time. The purpose of this study was to document the turnover in primate dental microwear through in vivo dental studies of monkeys raised on different diets, and through in vitro studies of the abrasive effects of monkey chow biscuits on isolated monkey teeth. As in previous studies, epoxy replicas were prepared from dental impressions and examined under a scanning electron microscope.Results indicate that, under certain conditions, the turnover in primate dental microwear can be on the order of days, hours, or even minutes. Individual microscopic wear features can be obliterated within 24 hours on the molars of laboratory monkeys, and monkey chow biscuits can easily scratch the enamel of isolated monkey teeth. Monkeys raised on a hard diet showed more rapid turnover i...
American Journal of Physical Anthropology, 1992
Recent microwear analyses have demonstrated that wear patterns can be correlated with dietary dif... more Recent microwear analyses have demonstrated that wear patterns can be correlated with dietary differences. However, much of this work has been based on analyses of museum material where dates and locations of collection are not well known. In view of these difficulties, it would be desirable to compare microwear patterns for different genera collected from the same area at the same time.The opportunity to do this was provided by the collections of the Smithsonian Venezuelan Project (Handley, 1976), in which multiple primate genera were collected from the same humid tropical forest sites within the same month. The monkeys represent a wide range of dietary preferences, and include Saimiri, Cebus, Chiropotes, Ateles, Aotus, Pithecia, and Alouatta.As in previous microwear analyses, epoxy replicas were prepared from dental impressions, as described by Rose (1983) and Teaford and Oyen (1989). Two micrographs were taken of facet 9 on an upper second molar of each specimen. Computations and...
Journal of Human Evolution, 1988
Recent paleontological fieldwork has led to the discovery of a palate and partial face of a young... more Recent paleontological fieldwork has led to the discovery of a palate and partial face of a young adult male Proconsul on Rusinga Island, Kenya. Morphologically, it is most similar to Proconsul nyanzae. However, it is intermediate in size between Proconsul nyonzae and Proconsul a&anus. Since the distinction between these two species, not to mention the relationship between Procon& from Rusinga and other sites, is not as clear as it once was, this specimen will undoubtedly add further fuel to the fire ofdiscussions and debates concerning early Miocene hominoid taxonomy. In particular, it shows that we have relied far too heavily on limited samples of crania-dental material in making our taxonomic assignments and distinctions.
Journal of Human Evolution, 2004
Journal of Human Evolution, 2006
Conventional wisdom ties the origin and early evolution of the genus Homo to environmental change... more Conventional wisdom ties the origin and early evolution of the genus Homo to environmental changes that occurred near the end of the Pliocene. The basic idea is that changing habitats led to new diets emphasizing savanna resources, such as herd mammals or underground storage organs. Fossil teeth provide the most direct evidence available for evaluating this theory. In this paper, we present a comprehensive study of dental microwear in Plio-Pleistocene Homo from Africa. We examined all available cheek teeth from Ethiopia, Kenya, Tanzania, Malawi, and South Africa and found 18 that preserved antemortem microwear. Microwear features were measured and compared for these specimens and a baseline series of five extant primate species (Cebus apella, Gorilla gorilla, Lophocebus albigena, Pan troglodytes, and Papio ursinus) and two protohistoric human foraging groups (Aleut and Arikara) with documented differences in diet and subsistence strategies. Results confirmed that dental microwear reflects diet, such that hard-object specialists tend to have more large microwear pits, whereas tough food eaters usually have more striations and smaller microwear features. Early Homo specimens clustered with baseline groups that do not prefer fracture resistant foods. Still, Homo erectus and individuals from Swartkrans Member 1 had more small pits than Homo habilis and specimens from Sterkfontein Member 5C. These results suggest that none of the early Homo groups specialized on very hard or tough foods, but that H. erectus and Swartkrans Member 1 individuals ate, at least occasionally, more brittle or tough items than other fossil hominins studied.
Vertebrate Paleobiology and Paleoanthropology, 2007
Fifty years ago, investigators realized they could gain insights into jaw movement and tooth-use ... more Fifty years ago, investigators realized they could gain insights into jaw movement and tooth-use through lightmicroscope analyses of wear patterns on teeth. Since then, numerous analyses of modern and fossil material have yielded insights into the evolution of tooth use and diet in a wide variety of animals. However, analyses of fossils and archeological material are ultimately dependent on data from three sources, museum samples of modern animals, living animals (in the wild or in the lab), and in vitro studies of microwear formation. These analyses are not without their problems. Thus, we are only beginning to get a clearer picture of the dental microwear of the early hominins. Initial work suggested qualitative differences in dental microwear between early hominids, but it wasn't until Grine's analyses of the South African australopithecines that we began to see quantitative, statistical evidence of such differences. Recent analyses have (1) reaffirmed earlier suggestions that Australopithecus afarensis shows microwear patterns indistinguishable from those of the modern gorilla, and (2) shown that the earliest members of our genus may also be distinguishable from each other on the basis of their molar microwear patterns. While this work hints at the possibilities of moving beyond standard evolutionary-morphological inferences, into inferences of actual differences in tooth use, we still know far too little about the causes of specific microwear patterns, and we know surprisingly little about variations in dental microwear patterns (e.g., between sexes, populations, and species). In the face of such challenges, SEM-analyses may be reaching the limits of their usefulness. Thus, two methods are beginning to catch attention as possible "next steps" in the evolution of dental microwear analyses. One technique involves a return to lower magnification analyses, using qualitative assessments of microwear patterns viewed under a light microscope. The advantages of these analyses are that they are cheap and fast, and may easily distinguish animals with extremely different diets. The disadvantages are that they are still subjective and may not be able to detect subtle dietary differences or artifacts on tooth surfaces. Another technique involves the use of scale-sensitive fractal analyses of data from a confocal microscope. Advantages include the ability to quickly and objectively characterize wear surfaces in 3D over entire wear facets. The main disadvantage lies in the newness of the technique and challenges imposed by developing such cutting edge technology. With the development of new approaches, we may be able to take dental microwear analyses to a new level of inference.
Pour La Science, 1989
Res. d'A. Soixante ans apres sa decouverte, Proconsul semble le dernier ancetre commun aux Gr... more Res. d'A. Soixante ans apres sa decouverte, Proconsul semble le dernier ancetre commun aux Grands Singes et a l'Homme
Scientific American, 1989
Sixty years after its discovery, Proconsul is now known to be the last common ancestor of great a... more Sixty years after its discovery, Proconsul is now known to be the last common ancestor of great apes and human beings rather than an extinct ancestor of the chimpanzee and the gorilla
Journal of Zoology, 1990
With 3 plates and 4 figures in the text) Patterns of dental microwear provide some of the best in... more With 3 plates and 4 figures in the text) Patterns of dental microwear provide some of the best indirect evidence of tooth use and diet in living and extinct species, and thus can supplement inferences based on gross morphology. In this paper, dental microwear features are examined in the extinct sabretooth cat Smilodon fatalis and among eight species of extant large carnivores, including felids, canids, hyaenids and a mustelid. Although all the living species are primarily carnivorous, some differ in the relative quantities of large bones consumed; hyaenas are the most frequent bone-crushers and cheetahs the least. Because bone is harder than meat, interspecific differences in bone consumption are expected to be reflected by differences in microwear pattern. Scanning electron micrographs of the wear facet of the lower first molar (carnassial) were used to estimate the average density, size, shape and orientation of microwear features for each species. Results indicate that dietary differences are highlighted when features shorter than 30 pm in length are excluded from the analysis. When this is done, hyaenas are distinguished from other species by a combination of relatively few long features and a high proportion of pits to scratches. By contrast, the cheetah is characterized by a predominance of narrow features, relatively few of which are pits. Species of intermediate diet, such as the wolf, leopard, wild dog and wolverine, tend to be intermediate in pit density and feature shape. Comparisons of the carnivore microwear data with that published for primates reveal that the eight carnivores are most similar to frugivorous primates that specialize on relatively hard fruits. In addition, the orientation of microwear features is significantly more variable in carnivores than in the only comparably studied primate, the chimpanzee. This suggests that many of the microwear features on the carnassial are produced by food moving in directions other than occlusal pathways. The pattern of microwear features in the sabretooth cat is distinct from all of the sampled extant carnivores. Smilodon has relatively narrow, long features and an extremely low pit frequency. Thus Smilodon probably consumed less bone than does the cheetah and may have left behind significant amounts of bone and meat for scavengers. The sabretooth cat may have avoided bone in order to protect its long canines from breakage.
The Journal of Prosthetic Dentistry, 1988
Journal of Human Evolution, 1988
In 1984 a joint National Museums of Kenya-Johns Hopkins University party began studies on the iso... more In 1984 a joint National Museums of Kenya-Johns Hopkins University party began studies on the isolated and unusual site known as R114 or "Whitworth's Pot-hole" at the northwest extremity of Rusinga Island, western Kenya, from which the partial skeleton of Proconsul africanus, KNM-RU 2036 was recovered in 195 1 (Napier & Davis, 1959; Walker & Pickford, 1983). We have published a brief note on the geology and taphonomy of the site and the recovery of additional bones from the skeleton (Walker et al., 1986). Here, we give a preliminary account of remarkably complete remains from several Proconsul individuals found together at site R5 on Kaswanga Point, 3 km east of R114.
Journal of Human Evolution, 1988
A hominoid proximal humerus from the Early Miocene of Rusinga Island, Kenya Recently, an isolated... more A hominoid proximal humerus from the Early Miocene of Rusinga Island, Kenya Recently, an isolated proximal humerus of an early Miocene hominoid was discovered at Rusinga Island, Kenya. The precise tasonomic allocation of this specimen is currently problematic. but the fossil almost certainly belongs to either Dendropithecus macinne~i or Proconsul aj%canus. The humeral head 1s expanded above the greater tuberosity in the new fossil suggesting that this early Miocene hominoid possessed a relatively mobile shoulder joint for climbing as well as for postural and feeding activities, and that rapid protraction at the shoulder joint was not important. This proximal humeral morphology contrasts with that of Aegyptopithecus, but is quite similar to that of Pliopithecus. Among extant primates, a similar proximal humeral morphology occurs in several platyrrhines such as Alouatta, but living apes share several apparently derived features of the proximal humerus which are lacking in the Rusinga Island specimen.
Journal of Human Evolution, 1991
Journal of Human Evolution, 1991
Journal of Human Evolution, 1989
The criteria traditionally used to distinguish between species of Proconsul have been largely siz... more The criteria traditionally used to distinguish between species of Proconsul have been largely size-related and based primarily on the dentition. Wt. present here new estimates of body mass for seven Proconml from earl\ Miocene (17.8 mybp) sites on Rusinga and Mfangano Islands. Kenya, derived from cross-sectional diaphyseal and articular dimensions of the femur, structural features that bear a close functional relationship to body mass in living species. The fossil specimens cluster into two major groups: one at just over 9 kg (including the well-known KNM-RU 2036), and the other between about 26 and 38 kg. Since a 3: 1 to 4: I body mass ratio between males and females of the same species is unknown among living primates or indeed land mammals, it seems most probable, contrary to some recent hypotheses, that at least two species ofProcomu1 are represented at these sites-the larger P. nyanza~ and the smaller a new species formerly identified as P. africanus. The P. nyanzne specimens can be further divided into subgroups ofabout 35-38 kg and 2628 kg, which may represent males and females of this species. In terms of size and general proportions, the f. nyanrae femora are most similar to those of pygmy chimpanzees, while the smaller Procoltstil femora are similar to those ofsome living cercopithecines. The P. nynn~ne femora also show evidence of a relatively mobile (ape-like) hip joint. However, in certain respects the general hindlimh bone proportions of the largest living cercopithecines and smallest great apes arc similar, overlapping within the body size range ofP. nyanrae, i.e., near 30 kg. The relatively shorter and thus more robust appearing femora of the larger living African apes may be a result of mechanical constraints associated with climbing in an anthropoid with a body mass significantly above this size range. which nevertheless remains the most commonly used characteristic for estimating body 0047-2484/89/0605
Journal of Dental Research, 1991
Human tooth wear occurs so slowly that traditionally it has needed months or years to be measurab... more Human tooth wear occurs so slowly that traditionally it has needed months or years to be measurable. This study showed that microscopic changes in wear patterns on human teeth could be detected in a matter of days and could be used as indicators of rates of wear. Thus, daily or weekly changes in rates of wear can be documented for specific locations on teeth. For instance, through this new approach, rates of wear of human teeth were shown to be significantly slower than rates of wear of the teeth of laboratory monkeys raised on hard or soft diets. Similar techniques may ultimately be used to monitor subtle changes in tooth use-including those associated with growth and development and those occurring in response to various dental clinical procedures.
Folia Primatologica, 1995
Leaves of two plant species eaten by Macaca fascicularis in Bukit Timah Nature Reserve, Singapore... more Leaves of two plant species eaten by Macaca fascicularis in Bukit Timah Nature Reserve, Singapore, were collected and colour-tested. Leaves matching those eaten by M. fascicularis were examined by energy-dispersive X-ray micro-analysis. The leaves of Streblus elongatus (Moraceae) and Gluta wallichii (Anacardiaceae), together forming 19.6% of the leaf diet of the macaques, contained silica. In G. wallichii, this is in the base of hairs that project from the underside of the leaf, whereas S. elongatus leaves have short sharp siliceous trichomes which are densely packed on the undersurface of leaf veins. We predict from an indentation analysis that chewing on the latter species could cause dental microwear at low occlusal forces. The leaves are reportedly common in the diet of three other primate species in peninsular Malaysia and the finding could have general significance for studies of dental wear.
Folia Primatologica, 1989
Tooth microwear studies have been carried out for several reasons in the last decade. Most effort... more Tooth microwear studies have been carried out for several reasons in the last decade. Most effort has been put into categorizing wear types that reflect dietary preferences in order to reconstruct the diet of extinct species. Several studies have shown that, for primates, carnivores and ruminants, it is possible to differentiate statistically the microwear associated with the major dietary adaptations in the group. It has further been found that more subtle dietary changes, such as seasonal ones, can be picked up if the sampling is good enough. It is important to recognize that, although it may be a valuable and legitimate concern to study the specific causes of different microwear patterns, that information is not essential for dietary reconstruction, if different microwear states can be shown empirically to correspond to different dietary regimes. Image enhancement and optical diffraction methods offer hope of automated scanning of large samples. This will be a major benefit as th...
American Journal of Physical Anthropology, 1984
Studies of dental microwear have been used to relate tooth form to function in a variety of recen... more Studies of dental microwear have been used to relate tooth form to function in a variety of recent and extinct mammals. Probably the most important aspect of microwear analysis is the possibility of using it to deduce the diet of extinct animals. Such deductions must be based on comparative studies of modern species with known diets, but to date, only qualitative studies have been attempted and all have been based on small samples. Here we report quantitative differences in dental microwear between primate species that are known to have different diets. Occlusal facets with different functions have previously been shown to exhibit different microwear patterns. However, the differences between facets of one species are shown to be far less than those between homologous facets of different species. Study of seven species of extant primates shows that enamel microwear can be used to distinguish between those with a mainly frugivorous diet and those with a mainly folivorous one. Microwear can also distinguish hard-object feeders from soft-fruit eaters. The microwear of Miocene Sivapithe cus indicus cannot be distinguished statistically from that of the chimpanzee, but it is different from that of the other species. On this evidence S. indicus was not a hard-object feeder and the adaptive significance of its thick molar enamel is a t present unknown.
American Journal of Physical Anthropology, 1989
Given the potential usefulness of dental microwear analyses in interpretations of archaeological ... more Given the potential usefulness of dental microwear analyses in interpretations of archaeological and paleontological material, it is surprising how little we know about changes in individual microwear features through time. The purpose of this study was to document the turnover in primate dental microwear through in vivo dental studies of monkeys raised on different diets, and through in vitro studies of the abrasive effects of monkey chow biscuits on isolated monkey teeth. As in previous studies, epoxy replicas were prepared from dental impressions and examined under a scanning electron microscope.Results indicate that, under certain conditions, the turnover in primate dental microwear can be on the order of days, hours, or even minutes. Individual microscopic wear features can be obliterated within 24 hours on the molars of laboratory monkeys, and monkey chow biscuits can easily scratch the enamel of isolated monkey teeth. Monkeys raised on a hard diet showed more rapid turnover i...
American Journal of Physical Anthropology, 1992
Recent microwear analyses have demonstrated that wear patterns can be correlated with dietary dif... more Recent microwear analyses have demonstrated that wear patterns can be correlated with dietary differences. However, much of this work has been based on analyses of museum material where dates and locations of collection are not well known. In view of these difficulties, it would be desirable to compare microwear patterns for different genera collected from the same area at the same time.The opportunity to do this was provided by the collections of the Smithsonian Venezuelan Project (Handley, 1976), in which multiple primate genera were collected from the same humid tropical forest sites within the same month. The monkeys represent a wide range of dietary preferences, and include Saimiri, Cebus, Chiropotes, Ateles, Aotus, Pithecia, and Alouatta.As in previous microwear analyses, epoxy replicas were prepared from dental impressions, as described by Rose (1983) and Teaford and Oyen (1989). Two micrographs were taken of facet 9 on an upper second molar of each specimen. Computations and...
Journal of Human Evolution, 1988
Recent paleontological fieldwork has led to the discovery of a palate and partial face of a young... more Recent paleontological fieldwork has led to the discovery of a palate and partial face of a young adult male Proconsul on Rusinga Island, Kenya. Morphologically, it is most similar to Proconsul nyanzae. However, it is intermediate in size between Proconsul nyonzae and Proconsul a&anus. Since the distinction between these two species, not to mention the relationship between Procon& from Rusinga and other sites, is not as clear as it once was, this specimen will undoubtedly add further fuel to the fire ofdiscussions and debates concerning early Miocene hominoid taxonomy. In particular, it shows that we have relied far too heavily on limited samples of crania-dental material in making our taxonomic assignments and distinctions.