bluuebunny/crossref_metadata_2025 huggingface dataset:
Dental development in South African australopithecines. Part I: Problems of pattern and chronology
Authors: Conroy Glenn C. , Vannier Michael W.
Published: February 2006

It is well known that humans take about twice as long as apes to mature. The traditional view that such delayed maturation was already present in australopithecines has been called into question during the past several years. We have approached this problem by looking at patterns of dental development in gracile and robust australopithecines from South Africa and comparing them to patterns found in extant humans and apes. We have employed both 2 and 3 dimensional computed tomography in our research. The dental growth patterns in these two australopithecine morphs differ, particularly in M1/I1 development. The robust australopithecines are more humanlike and the gracile australopithecines more apelike in this feature (“humanlike” and “apelike” are not used in any taxonomic sense). Pattern and chronology of dental development must be considered separately. Several major problem areas for future research are identified, most of which revolve around the issue of intra‐ versus interspecific variation.
Mixed longitudinal study of dental emergence in the chimpanzee, Pan troglodytes (primates, pongidae)
Authors: Conroy Glenn C. , Mahoney C. James
Published: February 2006

Dental emergence ages are examined for a mixed longitudinal sample of 58 chimpanzees of known age and sex (22 males, 36 females) followed over the past 10 years. This study provides the most complete data set currently available on dental emergence in chimpanzees of known age and sex. Summary statistics and cumulative frequency percentiles of emergence ages are presented for both the permanent and the primary teeth. Male and female percentiles are also compared and reveal a number of cases of sexual dimorphism in emergence ages. Comparisons of emergence means reveal some statistically significant differences between upper and lower teeth but not between antimeres in the upper or lower dentition. Kendall's rank correlation coefficient (tau) suggests a correlation in timing between first molar and incisor emergence within individuals. In addition, a significant time lag was observed between first molar and central incisor emergence. A number of emergence sequence polymorphisms are presented as well. These findings provide important baseline information for future studies of chimpanzee growth, development, and demography and also contribute to several current issues in paleoanthropology relating to dental maturation patterns in early hominids.
Aspects of dental development in the orangutan prior to eruption of the permanent dentition
Authors: Winkler L. A. , Schwartz J. H. , Swindler D. R.
Published: February 2006

In spite of a resurgence of interest in the interpretation of the sequences of dental development and eruption in various Plio‐Pleistocene hominoids as being either “modern human” or “ape‐like,” the body of comparative material on the extant hominoids remains deficient in critical areas. In concert with recent attempts to rectify this situation, we present the results of our studies on dental morphogenesis in the orangutan. We have focused on the growth and eruption of the deciduous dentition as well as early stages of permanent tooth formation and have found that 1) many permanent teeth develop earlier than was thought, 2) differences exist between development in the upper and in the lower jaw, and 3) states of tooth formation can vary significantly among individuals of similar chronological age or tooth eruption status.
Euclidean distance matrix analysis: A coordinate‐free approach for comparing biological shapes using landmark data
Authors: Lele Subhash , Richtsmeier Joan T.
Published: February 2006

For problems of classification and comparison in biological research, the primary focus is on the similarity of forms. A biological form can be conveniently defined as consisting of size and shape. Several approaches for comparing biological shapes using landmark data are available. Lele (1991a) critically discusses these approaches and proposes a new method based on the Euclidean distance matrix representation of the form of an object. The purpose of this paper is to extend this new methodology to the comparison of groups of objects. We develop the statistical versions of various concepts introduced by Lele (1991a) and use them for developing statistical procedures for testing the hypothesis of shape difference between biological forms. We illustrate the use of this method by studying morphological differences between normal children and those affected with Crouzon and Apert syndromes and craniofacial sexual dimorphism in Cebus apella.
Genetic variation of the mitochondrial DNA genome in American Indians is at mutation‐drift equilibrium
Authors: Chakraborty Ranajit , Weiss Kenneth M.
Published: February 2006

Several surveys have found evidence for founder effects in Amerindian mitochondrial DNA because of the existence of rare Asian morphs in high frequencies in some Amerindian populations and the occurrence of several new morphs not seen elsewhere in the world. These reports, however, do not address whether or not the present genetic variation in the mtDNA genome in Amerindians has reached the steady‐state distribution predicted by the mutation‐drift theory of population genetics. The present work suggests that in three Amerindian populations (Pima, Maya, and Ticuna) a steady state has apparently been reached, and hence the initial founder effect has probably dissipated during the evolution of Amerindians in the New World. This result is consistent with the genetic variation in nuclear genes in similar populations, shown through surveys of protein variation in earlier work and, more recently, in studies of restriction fragment length polymorphisms.
Sexual dimorphism in the human bony pelvis, with a consideration of the Neandertal pelvis from Kebara cave, Israel
Authors: Tague Robert G.
Published: February 2006

Sexual dimorphism of the human pelvis is inferentially related to obstetrics. However, researchers disagree in the identification and obstetric significance of pelvic dimorphisms. This study addresses three issues. First, common patterns in dimorphism are identified by analysis of pelvimetrics from six independent samples (Whites and Blacks of known sex and four Amerindian samples of unknown sex). Second, an hypothesis is tested that the index of pelvic dimorphism (female mean × 100/male mean) is inversely related to pelvic variability. Third, the pelvic dimensions of the Neandertal male from Kebara cave, Israel are compared with those of the males in this study.

The results show that the pelvic inlet is the plane of least dimorphism in humans. The reason that reports often differ in the identification of dimorphisms for this pelvic plane is that both the length of the pubis and the shape of the inlet are related to nutrition. The dimensions of the pelvis that are most dimorphic (that is, female larger than male) are the measures of posterior space, angulation of sacrum, biischial breadth, and subpubic angle. Interestingly, these dimensions are also the most variable. The hypothesis that variability and dimorphism are inversely related fails to be supported. The factors that influence pelvic variability are discussed.

The Kebara 2 pelvis has a spacious inlet and a confined outlet relative to modern males, though the circumferences of both planes in the Neandertal are within the range of variation of modern males. The inference is that outlet circumference in Neandertal females is also small in size, but within the range of variation of modern females. Arguments that Neandertal newborns were larger in size than those of modern humans necessarily imply that birth was more difficult in Neandertals. © 1992 Wiley‐Liss, Inc.
Maxillary canine/third premolar transposition in a prehistoric population from Santa Cruz Island, California
Authors: Nelson Greg C.
Published: February 2006

Canine/premolar transposition is rare in both historic and prehistoric Homo sapiens with a known occurrence of less than 0.10%. This report describes a prehistoric population sample from one site (SCrI‐3) on Santa Cruz Island, California in which the rate of C/P3 transposition is greater than eight percent, based on nine of 106 adult crania which exhibit the anomaly either uni‐ or bilaterally. As a means of investigating the etiology of this anomaly, the location of the canine root in adult crania was studied. Root location should indicate tooth bud origin, a factor likely to be under genetic control. In crania with normally erupted canines, the superior portion of the root averages 4.43 mm from alare, while this distance is 8.96 mm for anomalous roots. This difference suggests that during ontogeny the tooth buds for the canine and premolar arose in the wrong (or reversed) places, causing the teeth to erupt anomalously. It is suggested that inbreeding in a small island community resulted in a short‐lived appearance of this anomaly at a high frequency. © 1992 Wiley‐Liss, Inc.
Bantu βs cluster haplotype predominates among Brazilian Blacks
Authors: Zago Marco A. , Figueiredo Mauro S. , Ogo Satie H.
Published: February 2006

We describe the combination of polymorphic restriction‐enzyme sites in the β globin gene cluster (haplotypes) for 74 chromosomes from Brazilian Blacks bearing the sickle hemoglobin gene (βs). The three most common African βs haplotypes account for 67 chromosomes: 49/74 (66.2%) were identified as Central African Republic (CAR or Bantu) type, 17 (23.0%) as Benin, and one as Senegal; seven chromosomes (9.5%) had minor atypical haplotypes. This distribution is different from that observed in the United States or Jamaica, where the Benin haplotype predominates, and results from different patterns of slave trades to North and South Americas. Since the βs gene cluster polymorphisms modulate the severity of sickle cell anemia, this heterogeneity may explain differences of the clinical behavior of the disease in the United States and South America, and should also be considered in relation to other features and diseases. © 1992 Wiley‐Liss, Inc.
Dental microwear and diet in Venezuelan primates
Authors: Teaford Mark F. , Runestad Jacqueline A.
Published: February 2006

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 includeSaimiri,Cebus,Chiropotes,Ateles,Aotus,Pithecia, andAlouatta.

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 analyses were the same as described by Teaford and Robinson (1989).

Results reaffirm previously documented differences in dental microwear between primates that feed on hard objects versus those that do not—withPitheciaandAlouattaat the extremes of a range of microwear patterns including more subtle differences between species with intermediate diets. The subtle microwear differences are by no means easy to document in museum samples. However, additional results suggest that 1) the width of microscopic scratches may be a poor indicator of dietary differences, 2) large and small pits may be formed differently, and 3) there are very few seasonal differences in dental microwear in the primates at these humid tropical forest sites. © Wiley‐Liss, Inc.
Sex differences in adult chimpanzee positional behavior: The influence of body size on locomotion and posture
Authors: Doran Diane M.
Published: February 2006

Focal animal instantaneous sampling of adult male and female chimpanzee positional behavior was conducted during a 7‐month study in the Tai Forest, Ivory Coast, in order to determine whether there are sex differences in the locomotion, posture, substrate use, and height preference of sexually dimorphic adult chimpanzees, and if so, whether these differences support predictions based on body size differences. Results indicate that as predicted, adult male and female chimpanzees differ in their arboreal locomotor behavior, with the larger males using less quadrupedalism and more climbing, scrambling, and aided bipedalism than females during feeding locomotion. There is a sex difference in height preference as well, with female chimpanzees consistently using more arboreal behavior than males, primarily during resting. Although it has been previously demonstrated that separate primate species of differing body size differ in locomotor and postural activities (Fleagle and Mittermeier, 1980; Crompton, 1984), this study clearly demonstrates that body size differences within a species can also be correlated with differences in locomotor behavior. These findings may influence how we interpret sex differences in body size of extinct species. © 1993 Wiley‐Liss, Inc.
Population prehistory of East Asia and the pacific as viewed from craniofacial morphology: The basic populations in East Asia, VII
Authors: Hanihara Tsunehiko
Published: February 2006

Distance analyses were applied to 11 craniofacial measurements recorded in samples from East and Southeast Asia, Australia, Melanesia, Polynesia, and Micronesia for the purpose of assessing the biological affinities and possible origins of these populations. A clear separation between Australomelanesians and other populations from East and Southeast Asia and the Pacific is evident. The craniofacial variations suggest that the generalized Asian populations (Negritos, Dayaks, Lesser Sunda Islands, etc.) represent at least part of the morphological background of not only the majority of present Southeast Asians, but also the Neolithic Jomon people and their lineage in Japan, Polynesians, and western Micronesians. The original craniofacial features of Southeast Asians may have occurred as the result of convergent microevolution due to similar environmental conditions such as tropical rain forest. This supports the local‐evolution hypothesis for modern Southeast Asian craniofacial features. © 1993 Wiley‐Liss, Inc.
Basicranial flexion, relative brain size, and facial kyphosis in nonhuman primates
Authors: Ross Callum F. , Ravosa Matthew J.
Published: February 2006

Numerous hypotheses explaining interspecific differences in the degree of basicranial flexion have been presented. Several authors have argued that an increase in relative brain size results in a spatial packing problem that is resolved by flexing the basicranium. Others attribute differences in the degree of basicranial flexion to different postural behaviors, suggesting that more orthograde animals require a ventrally flexed pre‐sella basicranium in order to maintain the eyes in a correct forward‐facing orientation. Less specific claims are made for a relationship between the degree of basicranial flexion and facial orientation. In order to evaluate these hypotheses, the degree of basicranial flexion (cranial base angle), palate orientation, and orbital axis orientation were measured from lateral radiographs of 68 primate species and combined with linear and volumetric measures as well as data on the size of the neocortex and telencephalon. Bivariate correlation and partial correlation analyses at several taxonomic levels revealed that, within haplorhines, the cranial base angle decreases with increasing neurocranial volume relative to basicranial length and is positively correlated with angles of facial kyphosis and orbital axis orientation. Strepsirhines show no significant correlations between the cranial base angle and any of the variables examined. It is argued that prior orbital approximation in the ancestral haplorhine integrated the medial orbital walls and pre‐sella basicranium into a single structural network such that changes in the orientation of one necessarily affect the other. Gould's (“Ontogeny and Phylogeny.” Cambridge: Belknap Press, 1977) hypothesis, that the highly flexed basicranium of Homo may be due to a combination of a large brain and a relatively short basicranium, is corroborated. © 1993 Wiley‐Liss, Inc.
Growth of the fetus in the abdominal cavity
Authors: Abitbol M. Maurice
Published: February 2006

The ratio pelvic/abdominal cavity is 6.9% in samples of nonhuman mammals and nonhuman primates, and rises to approximately 30% in humans. This relative reduction of the abdomen and increase of the pelvis is associated with a partial or total shift of some organs from the abdomen to the pelvis: rectosigmoid colon, bladder, and genital organs, which are mostly abdominal in quadrupeds and are mostly pelvic in humans. Pregnancy, always abdominal in nonhumans, is pelvic during the first trimester and becomes abdominal later on in humans. Near term the pregnancy expands easily in nonhumans in view of relatively small fetus and relatively large abdominal cavity. But, for the opposite reasons (large fetus, small abdomen), the human pregnancy is limited space‐wise during its abdominal expansion. Unlike that of nonhumans, human pregnancy is faced with multiple problems. These include: 1) “squeezing” between the anterior abdominal wall and the lordosis of the lumbar spine; 2) compression of the aortocaval vessels; and 3) forward expansion of the abdomen resulting in reorientation of the trunk during erect posture as the pregnant woman approaches term. All these conditions are responsible for numerous pathological entities that occur during human pregnancy and are almost unknown in nonhuman mammals. © 1993 Wiley‐Liss, Inc.
Histological reconstruction of dental development and age at death of a juvenile Paranthropus robustus specimen, SK 63, from Swartkrans, South Africa
Authors: Dean M. C. , Beynon A. D. , Thackeray J. F. , Macho G. A.
Published: February 2006

There has been disagreement about whether the earliest hominids grew in a similar manner to great apes or modern humans. This has important biological implications, since it may have been inappropriate to apply modern human developmental standards to early hominids. The aim of the present study was to combine data from replicas of tooth surfaces, computed tomographic (CT) scans, and radiographs with data from a histological section of the canine crown, in order to provide a complete description of tooth crown and tooth root development in a single early hominid specimen (SK 63). Although partially destructive in nature, we have been able to determine the most reliable data yet for aspects of dental development in an important juvenile early hominid specimen. Appositional enamel formation time in the permanent right canine was estimated at between 305 and 418 days, imbricational enamel formation time at 819 days, and total crown formation time at between 3.18 and 3.48 years. The most likely age at death was estimated at around 4 years with a range of ages calculated between 3.18 and 4.23 years based on differences in timing of initial mineralization of the canine and differences in appositional enamel formation times. Crown formation times of the lower central and lateral incisors were estimated between 2.35–2.68 years and 2.57–2.91 years, respectively. Crown formation time of the first permanent molar was estimated at 2.4 years. Wear facets on the first permanent molars indicate that gingival emergence had occurred sometime prior to death, between 3 and 4 years of age. Estimates of root extension rates in the first permanent molars and in the permanent incisors are fast, and either within or above ranges of rates estimated for modern great apes. While we recognize that data for one individual may not be representative of data for a whole population of early hominids, the data for age at death, for age of M1 emergence, and for root extension rates presented here accord with those known for modern great apes and fall beyond the known ranges for modern humans. © 1993 Wiley‐Liss, Inc.
Ratios as a size adjustment in morphometrics
Authors: Albrecht Gene H. , Gelvin Bruce R. , Hartman Steve E.
Published: February 2006

Simple ratios in which a measurement variable is divided by a size variable are commonly used but known to be inadequate for eliminating size correlations from morphometric data. Deficiencies in the simple ratio can be alleviated by incorporating regression coefficients describing the bivariate relationship between the measurement and size variables. Recommendations have included: 1) subtracting the regression intercept to force the bivariate relationship through the origin (intercept‐adjusted ratios); 2) exponentiating either the measurement or the size variable using an allometry coefficient to achieve linearity (allometrically adjusted ratios); or 3) both subtracting the intercept and exponentiating (fully adjusted ratios). These three strategies for deriving size‐adjusted ratios imply different data models for describing the bivariate relationship between the measurement and size variables (i.e., the linear, simple allometric, and full allometric models, respectively). Algebraic rearrangement of the equation associated with each data model leads to a correctly formulated adjusted ratio whose expected value is constant (i.e., size correlation is eliminated). Alternatively, simple algebra can be used to derive an expected value function for assessing whether any proposed ratio formula is effective in eliminating size correlations. Some published ratio adjustments were incorrectly formulated as indicated by expected values that remain a function of size after ratio transformation. Regression coefficients incorporated into adjusted ratios must be estimated using least‐squares regression of the measurement variable on the size variable. Use of parameters estimated by any other regression technique (e.g., major axis or reduced major axis) results in residual correlations between size and the adjusted measurement variable. Correctly formulated adjusted ratios, whose parameters are estimated by least‐squares methods, do control for size correlations. The size‐adjusted results are similar to those based on analysis of least‐squares residuals from the regression of the measurement on the size variable. However, adjusted ratios introduce size‐related changes in distributional characteristics (variances) that differentially alter relationships among animals in different size classes. © 1993 Wiley‐Liss, Inc.
Linear measurements of cortical bone and dental enamel by computed tomography: Applications and problems
Authors: Spoor C. Fred , Zonneveld Frans W. , Macho Gabriele A.
Published: February 2006

This paper explores the potential of high‐resolution computed tomography (CT) as a morphometric tool in paleoanthropology. The accuracy of linear measurements of enamel thickness and cortical bone thickness taken from CT scans is evaluated by making comparison with measurements taken directly from physical sections. The measurements of cortical bone are taken on extant and fossil specimens with and without attached matrix, and the dental specimens studied include a sample of 12 extant human molars. Local CT numbers (representing X‐ray, attenuation) are used to determine the exact position of the boundaries of a structure. Using this technique most studied dimensions, including four of human molar enamel thickness, could be obtained from CT scans with a maximum error range of ±0.1 mm. The limitations of the method are discussed with special reference to problems associated with highly mineralized fossils. © 1993 Wiley‐Liss, Inc.
Orientation of the masseter muscle and the curve of Spee in relation to crushing forces on the molar teeth of primates
Authors: Osborn J. W.
Published: February 2006

A highly significant correlation is demonstrated between the forward inclination of the superficial masseter muscle and the forward tilt of molar teeth in the sagittal plane, conforming to the posterior end of the curve of Spee. The skulls studied included New and Old World monkeys, anthropoid apes, man, and a selection of other mammals. There was a wide variation between the angles measured in different animals (from 54° to 115°). The tilt of the curve of Spee increases the crush/shear ratio of the force produced on food between the posterior molars. The parallel tilt of superficial masseter maximizes the efficiency with which this muscle contributes to the crush component of the bite force in the sagittal plane. © 1993 Wiley‐Liss, Inc.
Taxonomic affinity of the early Homo cranium from Swartkrans, South Africa
Authors: Grine F. E. , Demes B. , Jungers W. L. , Cole T. M.
Published: February 2006

A quantitative analysis that employs randomization methods and distance statistics has been undertaken in an attempt to clarify the taxonomic affinities of the partial Homo cranium (SK 847) from Member 1 of the Swartkrans Formation. Although SK 847 has been argued to represent early H. erectus, exact randomization tests reveal that the magnitude of differences between it and two crania that have been attributed to that taxon (KNM‐ER 3733 and KNM‐WT 15000) is highly unlikely to be encountered in a modern human sample drawn from eastern and southern Africa. Some of the variables that differentiate SK 847 from the two early H. erectus crania (e. g., nasal breadth, frontal breadth, mastoid process size) have been considered to be relevant characters in the definition of that taxon. Just as the significant differences between SK 847 and the two early H. erectus crania make attribution of the Swartkrans specimen to that taxon unlikely, the linkage of SK 847 to KNM‐ER 1813, and especially Stw 53, suggests that the Swartkrans cranium may have its closest affinity with H. habilis sensu lato. Differences from KNM‐ER 1813, however, hint that the South African fossils may represent a species of early Homo that has not been sampled in the Plio‐Pleistocene of eastern Africa. The similarity of SK 847 and Stw 53 may support faunal evidence which suggests that Sterkfontein Member 5 and Swartkrans Member 1 are of similar geochronological age. © 1993 Wiley‐Liss, Inc.
Interpretation of low body mass indices: Australian aborigines
Authors: Norgan N. G.
Published: February 2006

Low body mass index (BMI kg/m2) has been proposed as a practical measure of energy undernutrition although it has some well‐known limitations. Some reports have suggested that those Australian Aborigines living a largely traditional way of life have low BMI without compromised health status and may have paradoxically high levels of subcutaneous adipose tissue.

The evidence for low BMI, in Australian Aborigines is reviewed from the mean data of 1,174 individuals in 26 groups of adults and from the individual data of 349 of these individuals, collected before 1970. Three of the nine groups of women had mean BMI less than 18.5 kg/m2 and 4% of the individual men and 14% of the individual women had values less than 16kg/m2, a value regarded as indicating severe chronic energy deficiency. Skinfold thicknesses were greater than expected from the BMI, suggesting paradoxically high subcutaneous fatness. The contribution of long‐leggedness to low BMI was estimated from the regression of BMI on the sitting height to stature ratio (SH/S). For the 26 groups, this was estimated to be 2 kg/m2, r2 = 31%. The relationship was weaker with the individual data, r2 = 15%. Body shape as evinced by low SH/S does contribute to low BMI in these Australian Aborigines. Single cut‐offs of BMI are not applicable to all population groups and allowance may have to be made for body form when using BMI to assess nutritional status. © 1994 Wiley‐Liss, Inc.
Morphological adaptation to diet in platyrrhine primates
Authors: Anapol Fred , Lee Sarah
Published: February 2006

Morphological features of the jaws and teeth are examined in eight species of platyrrhine monkeys that coexist in the Suriname rainforest. Z‐scores calculated from geometric predictions for several features of the feeding apparatus thought to have some functional significance (e. g., tooth dimensions, jaw robusticity, leverage of primary jaw elevators) are compared to a profile of the naturalistic dietary behavior of these species (i. e., proportions of fruit mesocarp, seeds, leaves, and fauna eaten).

Several features are found exclusively in those platyrrhines whose dietary preferences are the most limited. Such specializations appear to be associated with a particular protein source exploited by a species to supplement a largely frugivorous diet. Ateles paniscus, which feeds primarily on the mesocarp of ripe fruit, has an adaptive morphology that emphasizes broad incisors. Chiropotes satanas (and to a slightly lesser extent, Pithecia pithecia) is a frugivore/seed predator with large upper and lower canines and a robust mandible. The frugivore/folivore Alouatta seniculus has a relatively large total molar area and effective mandibular condyle height. In all four of these strictly vegetarian species, the leverage of the masseter muscle is greater than that of temporalis.

Of the omnivorous species, Cebus apella and C. nigrivittatus exploit both fauna and seeds for protein and exhibit an array of many of the above features, such as large teeth and thick mandibles. Saimiri sciureus, not particularly known for seed predation, departs from Cebus in having less robust canines and a more gracile mandible. All three cebid omnivores have a temporalis with greater leverage than the masseter, indicating a requirement for resisting anteriorly directed forces, for example, using the jaws for vigorous foraging. The lack of any enlarged features, other than incisors, in the omnivorous Saguinus midas may be attributable to the functional constraints of small body size. Because the small size of the gape limits the size of the food parcel ingested, a requirement to enlarge other dentomandibular structures for trituration is alleviated.
The skull attributed to Mozart—craniosynostosis or not?
Authors: Hauser Gertrud , Kritscher Herbert
Published: February 2006

The results of a detailed morphological analysis of the skull attributed to Mozart are presented which refute a recent claim that the skull as well as several of Mozart's portraits show indications of uncomplicated trigonocephaly. These indications according to the present analysis are within the limits of normal variation and derive from retention of part of the long arm of the anterior fontanelle.
Locomotion in captive Leontopithecus and Callimico: A multimedia study
Authors: Rosenberger Alfred L. , Stafford Brian J.
Published: February 2006

Video studies, gait analysis, footprint tracks, and observational scan sampling show that, in comparably furnished enclosures, Leontopithecus rosalia and Callimico goeldii are superficially similar in their use of predefined locomotor patterns but differ profoundly in many underlying details which reflect differences in postcranial morphology. Each uses pronograde arboreal quadrupedal walking, quadrupedal bounding, and vertical climbing with comparable frequency, and both shift to bounding while moving quadrupedally at high speeds. In walking, both species use a diagonal sequence gait. However, in Callimico the distance per bout traveled while walking or running is shorter than in L. rosalia and there is an emphasis on leaping (from a stationary position) and bounding‐leaps (saltational extensions of pronograde quadrupedalism), in contrast with the basically quadrupedal style of L. rosalia. This dichotomy is consistent with anatomical specializations, such as forelimb elongation in Leontopithecus and hindlimb elongation in Callimico. In vivo hand‐ and footprint studies demonstrate grasping halluces in both species while walking. Limb stances in L. rosalia during “transaxial bounding” involve an overstriding hindlimb, a predominance of oblique rather than in‐line travel, and unique hand and foot positions. Anatomically, this locomotor style may be associated with reduced dexterity of the elongate hands and a relatively short hallux. The captive locomotor profiles for both species probably reflect biased samples of the locomotor repertoire of their wild counterparts. Nevertheless, these data reflect species‐specific integrations of locomotor behavior and morphology, and corroborate expectations of locomotor diversity among callitrichine primates, even those of similar body size. It is suggested, however, that conventional quantitative studies of locomotor profiles may prove inadequate for resolving subtle aspects of locomotor morphology and behavior. © 1994 Wiley‐Liss, Inc.
Articular structure and function in Hylobates, Colobus, and Papio
Authors: Rafferty Katherine L. , Ruff Christopher B.
Published: February 2006

It has been demonstrated in clinical and experimental studies that subarticular trabecular bone responds to mechanical loads transmitted across joints through changes in mass and structural organization. We investigated differences in mass, volume, and density of subarticular trabecular bone of the humeral and femoral head in Hylobates syndactylus, Colobus guereza, and Papio cynocephalus. Our hypothesis was that variations in trabecular properties between taxa may reflect differences in mechanical loading associated with different locomotor repertoires. A nondestructive method for measuring trabecular properties using optical luminance data measured from radiographs was developed. We also examined the relationship between internal trabecular properties and the external size and surface area of the humeral and femoral heads in these taxa. Our results suggest that internal and external articular structure are relatively independent of each other and may be adapted to different aspects of the mechanical environment. Differences in trabecular mass between taxa appear to correspond to differences in the magnitudes of mechanical loads borne by the joint, whereas aritcular volume and surface area are related primarily to differences in joint mobility. Because of the apparent physiological “de‐coupling” of articular mass and volume, variations in articular density (mass/volume) are difficult to interpret in isolation. Comparisons of internal and external articular structure may provide new ways to reconstruct the locomotor/positional behavior of extinct taxa. © 1994 Wiley‐Liss, Inc.
Human dento‐gnathic metric variation in mesolithic/neolithic Ukraine: Possible evidence of demic diffusion in the Dnieper Rapids region
Authors: Jacobs Kenneth
Published: February 2006

Dental and gnathic metrics from a series of Mesolithic and Neolithic cemetery samples in the Dnieper River valley (Ukraine) are compared. Both male and female Neolithic samples have larger dental dimensions, wider dental arcades, and a more robust mandibular corpus than do the Mesolithic samples. In addition, the relative variances (RVs) of bucco‐lingual dental breadths (as measured by modified Levene's Tests) show an intriguing pattern of change from the Mesolithic into and through the Neolithic. Female RVs show a clear tenency to increase through time, while male RVs show more mixed tendencies. Such a pattern indicates that the increases in Ukrainian Neolithic dento‐gnathic dimensions are plausibly attributable to low intensity gene flow (demic diffusion). Seen in the light of new chronometric, paleodietary, and paleolinguistic information, as well as in the context of recent archaeological models for agro‐pastoralist origins in the North Pontic, these data suggest that gene flow via population interactions originating in or transient through the circum‐Caucasus may have played an important role in producing the Ukrainian Neolithic dental increase. © 1994 Wiley‐Liss, Inc.
Maternal mortality or prolonged growth: Age at death and pelvic size in three prehistoric Amerindian populations
Authors: Tague Robert G.
Published: February 2006

This study evaluates the relationship between age at death and pelvic size among adults in three prehistoric Amerindian populations. The issue is to identify if the pelvis continues to grow and remodel in adulthood, or if there is differential survivorship among adults, particularly among females, based on pelvic size. The samples used in this study are Indian Knoll, Pecos Pueblo, and Libben. Twenty‐one measures of the pelvis are analyzed. A correlational analysis among individuals 18 years of age and older shows that the subpubic angle narrows with advancing age in both sexes. The suggested etiology is osteophytic growth on the ischiopubic ramus among older adults. A two‐sample test comparing younger (ages 18–24) and older (25 years of age and older) adults shows that the linea terminalis (which represents the pubic and iliac components of the pelvic inlet) is significantly shorter in the younger age group, but this pattern is seen only in females. Two interpretations are consistent with this result. First, a female with a short linea terminalis (i. e., small pelvic inlet) may have died at a young age due to childbirth‐related complications. In prehistory, maternal mortality may have been a leading cause of death, with pelvic inlet capacity being a determinant of survivorship among parturients. Second, the linea terminalis may be unique by continuing to grow in early adulthood in females but not in males; the growth occurs at the medial border of the pubis. Longitudinal growth studies of modern humans provide support for the second interpretation. The selective advantage of a later age at maturation of the pubis in females than males is that the period of growth is prolonged, thereby contributing to sexual dimorphism in pubic length and, correspondingly, linea terminalis length and pelvic inlet circumference. © 1994 Wiley‐Liss, Inc.
Craniometric variation among modern human populations
Authors: Relethford John H.
Published: February 2006

Previous studies of genetic markers and mitochondrial DNA have found that the amount of variation among major geographic groupings of Homo sapiens is relatively low, accounting for roughly 10% of total variation. This conclusion has had implications for the study of human variation and consideration of alternative models for the origin of modern humans. By contrast, it has often been assumed that the level of among‐group variation for morphological traits is much higher. This study examines the level of among‐group variation based on Craniometric data from a large sample of modern humans originally collected by W. W. Howells. A multivariate method based on quantitative genetics theory was used to provide an estimate of FST — a measure of among‐group variation that can be compared with results from studies of genetic markers. Data for 57 Craniometric variables on 1,734 crania were analyzed. These data represent six core areas: Europe, Sub‐Saharan Africa, Australasia, Polynesia, the Americas, and the Far East. An additional set of analyses was performed using a three‐region subset (Europe, Sub‐Saharan Africa, and the Far East) to provide comparability with several genetic studies.

The minimum FST (assuming complete heritability) for the three‐region analysis is 0.065, and the minimum FST for the six‐region analysis is 0.085. Both of these are less than the average FST from genetic studies (average estimates of 0.10–0.11). The smaller value of the minimum FST estimates is expected since it provides an estimate of FST expected under complete heritability. Using an estimate of average craniometric heritability from the literature provides an estimate of FST of 0.112 for the three‐region analysis and 0.144 for the six‐region analysis. These results show that genetic and craniometric data are in agreement, qualitatively and quantitatively, and that there is limited variation in modern humans among major geographic regions. © 1994 Wiley‐Liss, Inc.
Altitude, language, and class I HLA allele frequencies in Papua New Guinea
Authors: Smith Tom , Bhatia Kuldeep , Prasad Madhuri , Koki George , Alpers Michael
Published: February 2006

Class I HLA gene frequencies show considerable variation over short geographical distances in Papua New Guinea. Hypotheses to account for this invoke natural selection, population structure, the pattern of population movement, or past demographic changes. To determine the role of the various factors in shaping this distribution, we have studied correlations between HLA‐based genetic distances, geographical distances, altitude, and linguistic differences in Papua New Guinea. Linguistic differences at the family or stock level within the Trans‐New Guinea Phylum generally correspond to genetic differences. However, on the basis of their HLA gene frequencies, speakers of Austronesian (AN) languages do not form a distinct group of populations. Linguistic variation and spatial autocorrelation do not fully account for the altitudinal cline differences noted in gene frequencies, particularly at the HLA‐A locus. We propose that the distribution of HLA gene frequencies in Papua New Guinea is partially under the control of selection operating differentially along the altitude gradient. © 1994 Wiley‐Liss, Inc.
Early ontogeny of the human femoral bicondylar angle
Authors: Tardieu Christine , Trinkaus Erik
Published: February 2006

The presence of a femoral bicondylar angle consistently and significantly greater than 0° has been a hallmark of hominid bipedality, but its pattern of development has not been documented. We have therefore compiled cross‐sectional data on the development of the articular bicondylar angle for a clinical sample of modern humans and of the metaphyseal bicondylar angle for two Recent human skeletal samples, one predominantly European in origin and the other Amerindian. All three samples exhibit a pattern of a bicondylar angle of 0° at birth and then a steady average increase in the angle from late in the first year postnatal, through infancy, and into the juvenile years. The two skeletal samples reach low adult values by approximately 4 years postnatal, whereas the clinical sample with a lowered activity level appears to attain consistent adult values slightly later (approximately 6 years postnatal). In addition, two modern human individuals, one nonambulatory and the other minimally ambulatory, show no and little development, respectively, of a bicondylar angle. These data, in conjunction with clinical and experimental observations on the potential and form of angular changes during epiphyseal growth, establish a high degree of potential for plasticity in the development of the human bicondylar angle and the direct association of a bipedal locomotion and (especially) posture with the developmental emergence of a human femoral bicondylar angle. © 1994 Wiley‐Liss, Inc.
Social implications of gummivory in marmosets
Authors: Harrison Mary L. , Tardif Suzette D.
Published: February 2006

Gummivory or exudate feeding is a major dietary specialization which has received relatively little attention in the literature. While plant exudates contribute to the diet of many primate species, we suggest that the callitrichid speciesCebuella pygmaeaandCallithrix jacchus are obligateexudate feeders under free‐ranging conditions.Callithrix jacchusprovides an excellent model for examining the effects of exudate feeding and foraging upon social behavior, since other callitrichid species of similar body size do not share this dietary specialization. We review the effects of exudate foraging on specific social behaviors observed both in field and laboratory populations ofC. jacchus. By comparing this species to closely related species, exudate foraging is seen to (1) be retained under laboratory conditions, (2) increase the frequency of territorial marking behavior while decreasing the frequency of overt aggression in males, (3) decrease the duration of infant care, and (4) increase the number of nonadults in social groups but not affect group size. The evidence presented supports the hypothesis that the consequences of exudate foraging inC. jacchusare fundamental and socially complex. © 1994 Wiley‐Liss, Inc.
Limb joint surface areas and their ratios in Malagasy lemurs and other mammals
Authors: Godfrey Laurie R. , Sutherland Michael R. , Paine Robert R. , Williams Frank L. , Boy Donald S. , Vuillaume‐Randriamanantena Martine
Published: February 2006

Surface areas of humeral and femoral heads scale largely as a function of body size. However, differences in the relative sizes of these articular surfaces are correlated with differential joint mobility and force transmission through fore‐ and hindlimbs. They can therefore assist interpretation of the positional behavior of extinct species. In this paper, we document variation in ratios of humeral head surface area to femoral head surface area among extant primates and other mammals. We then examine a group of extinct primates: the subfossil lemurs of Madagascar. Many Malagasy le murs, including some giant extinct species with very long forelimbs and short hindlimbs, have relatively small humeral heads and large femoral heads. We explore the adaptive implications of this pattern. © 1995 Wiley‐Liss, Inc.
Tigaran (Point Hope, Alaska) tooth drilling
Authors: Schwartz Jeffrey H. , Brauer Jaymie , Gordon‐larsen Penny
Published: February 2006

In a sample of 48 adult Tigarans (1300–1700 A.D.) from Point Hope, Alaska, 33 exhibited various degrees of periodontal disease, which, in 25, resulted in tooth loss (Schwartz, unpublished data). Although extreme examples of tooth wear were prevalent in the sample, carious infection was noted in only one individual, in whom the lower central incisors (I1s) had been affected. In the left I1 infection had spread through the root's apex into the alveolar bone, causing an abscess. The buccal (labial) side of the root of this tooth, just below the crown, bears a shallow, relatively flat‐bottomed depression, with a small perforation into, as well as a second hole that fully penetrates, the root canal. Both of these features appear to have been produced by an implement, and, as they are associated with a diseased tooth, and ritualistic tooth shaping or drilling of any sort was, and is, not practiced among Arctic groups, their purpose was probably therapeutic. As such, this specimen appears to represent a case of precontact New World Arctic dentistry. © 1995 Wiley‐Liss, Inc.
Statistical study of sexual dimorphism in the human fetal sciatic notch
Authors: Holcomb Susan M. C. , Konigsberg Lyle W.
Published: February 2006

Whether human fetal skeletal remains exhibit sexual dimorphism has been the subject of considerable debate. Most attention in this debate has focused on the greater sciatic notch of the ilium, since it is a gross morphological characteristic with known sex differences in the adult and is easily seen in fetal skeletal remains. Unfortunately, previous traditional morphometric analyses of the fetal sciatic notch have led to ambiguous results. The purpose of this study is to determine whether differences between the sexes can be discerned when modern morphometric techniques are applied to the fetal sciatic notch. Photographs of the ventral side of 133 fetal ilia of known age and sex from the Trotter Collection of Washington University were digitized, and the trace coordinates used for all subsequent analyses. The results of the analysis demonstrate that there is significant sexual dimorphism in the anterior to posterior location of the maximum depth of the sciatic notch, but that the depth of the notch itself is not dimorphic. While there is significant sexual dimorphism in the shape of the sciatic notch, the amount of overlap between males and females is too great for the sciatic notch to be used as a reliable indicator of sex. © 1995 Wiley‐Liss, Inc.