bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kin preference in marmosets and tamarins: Saguinus oedipus and Callithrix jacchus (callitrichidae, primates)
Authors: Harrison Mary L. , Tardif Suzette D. 
Published: February 2006

AbstractField studies on callitrichid primates have suggested that some species may exhibit a communal breeding system in which two or more males mate with a single female and cooperatively participate in infant rearing. However, high levels of aggression have been observed between males under both laboratory and field conditions. In avian models for communal breeding, cooperating males are often closely related. In a laboratory test of a hypothesis of the amelioration of aggression based on kinship, four mated pairs of both Saguinus oedipus and Callithrix jacchus were introduced to both novel male conspecifics and to their own male siblings, from whom they had been separated for a minimum of 4 months. Significant differences (P < .01) were seen in the responses of the two species to male conspecifics generally: S. oedipus males responded to intruders with overt aggression significantly more frequently than did marmosets while C. jacchus males more frequently scent‐marked than did tamarins. Evidence of preference for kin males was seen in the significantly decreased frequencies of these behaviors in the presence of kin males over those observed in the presence of novel males. It is argued that, under field conditions, cooperation between male callitrichids may be facilitated by kinship. Further, twin births, short gestation lengths, and interbirth intervals seen in callitrichid primates all contribute to the number of socially familiar kin with which an individual animal might cooperate.
Sexual selection and canine dimorphism in new world monkeys
Authors: Kay R. F. , Plavcan J. M. , Glander K. E. , Wright P. C. 
Published: February 2006

AbstractSocial and ecological factors are important in shaping sexual dimorphism in Anthropoidea, but there is also a tendency for body‐size dimorphism and canine dimorphism to increase with increased body size (Rensch's rule) (Rensch: Evolution Above the Species Level. London: Methuen, 1959.) Most ecologists interpret Rensch's rule to be a consequence of social and ecological selective factors that covary with body size, but recent claims have been advanced that dimorphism is principally a consequence of selection for increased body size alone. Here we assess the effects of body size, body‐size dimorphism, and social structure on canine dimorphism among platyrrhine monkeys.Platyrrhine species examined are classified into four behavioral groups reflecting the intensity of intermale competition for access to females or to limiting resources. As canine dimorphism increases, so does the level of inter‐male competition. Those species with monogamous and polyandrous social structures have the lowest canine dimorphism, while those with dominance rank hierarchies of males have the most canine dimorphism. Species with fission‐fusion social structures and transitory intermale breeding‐season competition fall between these extremes.Among platyrrhines there is a significant positive correlation between body size and canine dimorphism However, within levels of competition, no significant correlation was found between the two. Also, with increased body size, body‐size dimorphism tends to increase, and this correlation holds in some cases within competition levels.In an analysis of covariance, once the level of intermale competition is controlled for, neither molar size nor molar‐size dimorphism accounts for a significant part of the variance in canine dimorphism. A similar analysis using body weight as a measure of size and dimorphism yields a less clear‐cut picture: body weight contributes significantly to the model when the effects of the other factors are controlled. Finally, in a model using head and body length as a measure of size and dimorphism, all factors and the interactions between them are significant. We conclude that intermale competition among platyrrhine species is the most important factor explaining variations in canine dimorphism. The significant effects of size and size dimorphism in some models may be evidence that natural (as opposed to sexual) selection also plays a role in the evolution of increased canine dimorphism.
Group selection models with population substructure based on social interaction networks
Authors: Cheverud James M. , Diane Chepko‐Sade B. , Dow Malcolm M. , Sade Donald S. 
Published: February 2006

AbstractMost models of evolution by group selection assume that groups have discrete boundaries with homogeneous levels of interaction within groups and no interaction between groups. While this assumption is analytically useful, it is not an accurate description of groups in nature. We use a generalization of D.S. Wilson's (Am. Nat. 111:157–185, 1977; The Natural Selection of Populations and Communities. Reading, Mass.: Benjamin/Cummings, 1980) concept of trait‐groups, in which groups are defined as sets of interacting individuals, to estimate the average degree of relatedness among groomers and groomees, referred to here as grooming‐groups. The average degree of relatedness is an important parameter in models of both kin and group selection.Data on grooming among 52 female rhesus macaques drawn from Group F on Cayo Santiago were used to represent the pattern and intensity of affiliative interactions. Degrees of relatedness among individuals and transferrin phenotypes were obtained from demographic and genetic records on the colony. The average degree of relatedness within grooming‐groups was estimated directly by calculating the average degree of relatedness among interactants (groomers and groomees), weighted by their frequency of interaction. Average degrees of relatedness among interactants were also estimated from the subjective frequency of the transferrin C allele.Our analysis indicates that the average degree of relatedness within grooming‐groups is 0.316 when estimated directly and 0.347 when estimated from the subjective frequency of the transferrin C allele. These values are much higher than are usually considered for group selection in primate societies and indicate the relative ease with which altruism may evolve given primate social structures.
Statistical analysis of the migration component of genetic drift
Authors: Rogers Alan R. , Eriksson Aldur W. 
Published: February 2006

AbstractStatistical methods are introduced for analysis of the migration component of genetic drift, i.e., of the stochastic changes that affect allele frequences during migration between local groups. Attention focuses on αM, a parameter that measures the extent to which this component of drift departs from the ideal of independent random sampling, and which can be interpreted as a measure of the extent to which migration is kin‐structured. It is shown that αM can be estimated from genetic data, even in the absence of information about the genealogical relationships of migrants, and Monte‐Carlo simulations are used to approximate the sampling distribution of the estimator under the null hypothesis of independent random sampling. Application of these methods to data from the Åland Islands, Finland, shows that the migration pattern there is consistent with the hypothesis of independent random sampling.
Human dental reduction: Natural selection or the probable mutation effect
Authors: Calcagno James M. , Gibson Kathleen R. 
Published: February 2006

AbstractDental reduction has been sufficiently widespread among human populations to render the phenomenon of reduced tooth size worthy of scientific explanation. One of the most controversial models invoked to explain structural reduction in organisms is referred to as the “probable mutation effect” (PME). According to this model, structures no longer functional owing to ecological or cultural changes will experience a relaxation of selection pressure, permitting an accumulation of mutations in the population that inevitably will result in the reduction in size or the loss of the concerned structure. Although the PME continues to be offered as a viable explanation of human dental reduction, it is based upon several premises that modern dental clinical experience fails to support. Known enzyme defects resulting from mutations, factors predisposing to dental infections, and the deleterious effects of teeth that are too large or too small reveal that the PME does not logically account for the reduction of tooth size. Given such information, this paper proposes models of dental reduction based upon natural selection, which, unlike the PME, are testable in both modern and archaeological populations. The integration of clinical and skeletal data permits a more thorough understanding of dental reduction in the hominid fossil record.
Gluteus maximus muscle function and the origin of hominid bipedality
Authors: Marzke Mary W. , Longhill Julie M. , Rasmussen Stanley A. 
Published: February 2006

AbstractBipedality not only frees the hands for tool use but also enhances tool use by allowing use of the trunk for leverage in applying force and thus imparting greater final velocity to tools. Since the weight and acceleration of the trunk and forelimbs on the hindlimbs must be counteracted by muscles such as m. gluteus maximus that control pelvic and trunk movements, it is suggested that the large size of the cranial portion of the human gluteus maximus muscle and its unique attachment to the dorsal ilium (which is apparent in the Makapan australopithecine ilium) may have contributed to the effectiveness with which trunk movement was exploited in early hominid foraging activities. To test this hypothesis, the cranial portions of both right and left muscles were investigated in six human subjects with electromyography during throwing, clubbing, digging, and lifting. The muscles were found to be significantly recruited when the trunk is used in throwing and clubbing, initiating rotation of the pelvis and braking it as trunk rotation ceases and the forelimb accelerates. They stabilize the pelvis during digging and exhibit marked and prolonged activity when the trunk is maintained in partial flexion during lifting of heavy objects.
Human skeletal and dental remains from Lapita sites (1600–500 B.C.) in the Mussau Islands, Melanesia
Authors: Kirch Patrick V. , Swindler Daris R. , Turner Christy G. 
Published: February 2006

AbstractThe Lapita Cultural Complex, radiometrically dated to between 3,600 and 2,500 B.P., is regarded on archaeological evidence as ancestral to modern Austronesian‐speaking cultures of eastern Melanesia and Polynesia. To date, there has been a lack of human skeletal and dental material from Lapita sites; thus, the present sample from Mussau Island, although small, offers an opportunity to present some preliminary observations of their importance to Oceanic prehistory. The present analysis, based mainly on teeth, suggests that the Mussau Island Lapita people had slightly closer affinities with Indonesian than with Melanesian populations. These results correspond well with linguistic and archaeological evidence regarding the origin of the Lapita Cultural Complex.
The genetic structure of populations of Chuckotka Peninsula Eskimos and Chuckchi based on the study of 13 loci of serum and erythrocyte proteins and enzymes
Authors: Nazarova Ariadna F. 
Published: February 2006

AbstractThe Eskimos and Chuckchi of the Chuckotka Peninsula were studied at 13 loci of serum and erythrocyte proteins and enzymes by electrophoresis. Six loci—including albumin, transferrin, carbonic anhydrase I and II, monoamine oxidase, and superoxide dismutase—were monomorphic in the studied populations. The mean frequencies of alleles in nine polymorphic loci of Chuckotka Eskimos and Chuckchi, Eskimos of Alaska, Canada, and Greenland, some Mongoloid populations of Siberia, American Indians, and Lapps of circumpolar areas of Western Europe were obtained. The genetic distances between these populations were calculated. The Eskimos of Chuckotka were closest to the Alaskan Eskimos. The relative heterozygosity of Chuckotka Eskimos was calculated and was the highest in Chuckchi. The average heterozygosity in Eskimo populations increased in the following order, from least to greatest: Chuckotka Eskimos, St. Lawrence Island Eskimos, Alaskan Eskimos, Greenland Eskimos, and Canadian Eskimos. The average heterozygosity of the Chuckchi was similar to that of Western Hemisphere Eskimos.
Extreme seasonality of births among nomadic Turkana pastoralists
Authors: Leslie Paul W. , Fry Peggy H. 
Published: February 2006

AbstractBirths to nomadic Turkana women in northwest Kenya follow one of the most highly seasonal distributions ever reported for a human population, with more than half of all births falling between March and June. Important aspects of the Turkana environment also fluctuate greatly over the course of the year. The rate of conception is apparently highest during the early dry season, when the food supply has been at its best for some time, and when women are attaining their peak nutritional status. The seasonal dynamics of Turkana fertility seem to be driven, ultimately, by fluctuations in rainfall; Fourier analysis indicates that changes in numbers of conceptions follow changes in rainfall with a lag of 3.6 months. The specific biological and behavioral changes in the human population through which the environmental changes may affect fertility are considered.
Test of Phenice's technique for determining sex from the os pubis
Authors: Lovell Nancy C. 
Published: February 2006

AbstractPubic bone morphology was examined to test the accuracy of Phenice's visual method for determining sex from the os pubis. Twelve participants scored 50 pubic bones from individuals of known sex aged 52–92 years. The sample is of modern males and females, all presumed whites. An accuracy of ∼83% in determining sex was recorded, compared to 95% reported by Phenice. This accuracy difference may reflect different age distributions of the two samples. Through replication of test results on two series of 25 specimens, the technique was found to be reliable. Previous experience in human osteological analysis was shown to have no effect on accuracy in this test, confirming Phenice's assertion that the technique does not require extensive experience to yield accurate results. Results suggest that there is a moderate negative correlation between accuracy in determining the sex of an individual and that individual's age.
Comparison of t‐tests for differences in sexual dimorphism between populations
Authors: Greene David Lee 
Published: February 2006

AbstractA t‐test that can be used for evaluating the significance of differences in metric sexual dimorphism between populations is derived directly from mathematical considerations of the differences between distributions. It is compared with the t‐test derived by Relethford and Hodges (1985), which was based upon linear regression with sex as a dummy variable. Both are determined to be mathematically equivalent, though the one derived here is more similar in form to traditional t‐tests of differences and therefore may be simpler to employ. Both tests require only summary statistics for comparisons between populations and comparisons between generations within populations.
Sexual dimorphism in Laccopithecus robustus, a late Miocene Hominoid from China
Authors: Yuerong Pan , Waddle Diane M. , Fleagle John G. 
Published: February 2006

AbstractLaccopithecus robustus is a siamang‐sized fossil ape from the Miocene site of Lufeng, China. The species is known from a partial cranium, numerous mandibles, and scores of isolated teeth. This species shows striking dental similarities to Pliopithecus from the Miocene of Europe and a number of cranial similarities to extant gibbons. Laccopithecus differs from extant gibbons and resembles other fossil and extant apes in showing marked sexual dimorphism in the size and shape of the canines and anterior lower premolars. Evidence for sexual differences in either the size or shape of other teeth is less clear. There is some evidence for a sexual size dimorphism based on the variability of molar teeth.
Social and biological correlates of localized enamel hypoplasia of the human deciduous canine tooth
Authors: Skinner M. F. , Hung J. T. W. 
Published: February 2006

AbstractRecent studies of teeth from prehistoric children have reported a localized, roughly circular patch of deficient enamel on the labial aspect of the primary canine, which reaches its highest prevalence in the Upper Paleolithic of Europe. This study reports social and biological correlates of 33 affected kindergarten‐aged children from Vancouver, Canada (2.4% of 1,350 examined). Affected children can be characterized as coming from low‐income families often of East Asian or Chinese origin in which there is a degree of milk avoidance and reduced breastfeeding. The defect appears to be due to minor physical trauma to the face approximately 6 months after birth occasioned by normal motor development, involving handling and mouthing objects, which damages the developing tooth crown through deficient cortical bone over the canine crypt. Reduced cortical bone in the face of the infant is attributed to nutritional factors, involving calcium deficiency, of the mother and/or developing infant.
Population variation in tooth, jaw, and root size: A radiographic study of two populations in a high‐attrition environment
Authors: Smith Patricia , Wax Yochanan , Adler Fanny 
Published: February 2006

AbstractRadiographs were taken of the jaws of skeletal remains of two populations of different‐phenotype Prehistoric Australians from Roonka and Early New Zealanders (Maoris). On these radiographs crown, root, and corpus size were measured. Corpus height was subdivided into alveolar bone height, defined as the bone superior to the mandibular canal, and basal bone height, defined as that inferior to the mandibular canal. Both between and within the two populations there was a significant and negative correlation between crown size and corpus height. The differences between the two populations in corpus height were associated with differences in alveolar bone height rather than basal bone height and support hypotheses associating continued eruption of adult teeth with growth of the alveolar bone. The findings also support previous studies that have shown only a low correlation between crown size, root size, and corpus height.
Third molar agenesis in human prehistoric populations of the Canary Islands
Authors: De Castro José María Bermúdez 
Published: February 2006

AbstractThe occurrence of third molar agenesis was recorded in a sample of 1,492 maxillary and 1,718 mandibular arches belonging to the prehistoric settlers of the Gan Canaria, Tenerife, and La Gomera Islands (Canary Islands). There were significant sex differences only in the Tenerife sample for the maxilla, the incidence in females being higher than in males. In the Gran Canaria sample, the total frequency (male and female combined) of third molar agenesis (individual count method) was 8.7% for the maxilla and 9.3% for the mandible. In the Tenerife and La Gomera samples, the frequencies were 11.1% and 10.7% for the maxilla and 14.6% and 13.3% for the mandible. In the Tenerife sample, the differences between both jaws were statistically significant. The incidence of missing third molars in the mandible was significantly higher in Tenerife than in Gran Canaria, but the other sample differences were statistically nonsignificant. Bilateral absence of third molars was observed in about two‐thirds of the specimens examined. Some correlation between both jaws for the occurrence of third molar agenesis was found. The hypotheses that have been proposed in order to explain third molar agenesis in man are discussed. It is suggested that the loss of the third molar in Homo sapiens could be produced by a heterochronic phenomenon of postdisplacement, as a consequence of the phylogenetic tendency toward the delay of the onset of the third molar formation, and that the genetic factors responsible for the absence of these teeth could be related to the general process of delay in tooth formation.
Apparent age‐related bone loss among adult female Gombe chimpanzees
Authors: Sumner Dale R. , Morbeck M. E. , Lobick J. J. 
Published: February 2006

AbstractApparent age‐related bone loss among adult females was observed in a skeletal sample derived from the free‐ranging Gombe chimpanzee population of Tanzania. Photon absorptiometric and computed tomographic bone scans indicated that, as in humans, bone was lost from the endosteal surface, but, in contrast to humans, more bone was lost from cortical sites than from cancellous sites. The etiology of this bone loss may be related to a number of factors, including hormonal changes, nutritional inadequacy, and decreased physical activity late in life.coupled with the demands of pregnancy and lactation.
Developmental changes in the facial soft tissues
Authors: Burke P. H. , Hughes‐Lawson C. A. 
Published: February 2006

AbstractShort‐base stereophotogrammetry was used to study differential growth and development of the soft tissues of the face. Thirteen facial parameters were measured at ages 9, 11, 13, 15, and 16 years on 170 facial contour maps selected from a mixed longitudinal study of 26 boys and 26 girls. Each parameter was measured three‐dimensionally, and its developmental progress at the earlier stages was expressed as a percentage of its value at 16 years of age. Standing height development was assessed in the same way. Three parameters that measured soft tissues surrounding the eyes grew little but were very advanced in their development, following a “neural” pattern. The remaining facial parameters grew more but were less advanced, and standing height was least advanced. There appeared to be three separate patterns of development, “neural,” “facial,” and “skeletal.” Girls were, in general, smaller than boys, but their development was more advanced when measured as a percentage of size at 16 years compared with boys.
Treponematosis: A possible case from the late prehistoric of North Carolina
Authors: Reichs Kathleen J. 
Published: February 2006

AbstractThe skeleton of an adult female exhibiting evidence of trepo‐nemal infection was recently recovered from the Hardin site in the piedmont region of North Carolina. Archaeological indicators suggest a late prehistoric affiliation. The skeleton is affected by a diffuse process resulting in surface changes, both destructive and appositional, node formation and shaft expansion, medullary encroachment and filling, cortical thickening, and fracture. There is both cranial and postcranial involvement. While treponemal infection is indicated, the atypical nature of the total pattern raises the possibility of multiple pathological processes operating simultaneously.The significance of this case is threefold. It provides information on the ability of prehistoric peoples to cope with disease. It reminds the paleopathologist of the dangers inherent in attempts at singular and specific diagnoses. It sheds new light on the epidemiology of the treponemal diseases.