bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interspecific perspective on mechanical and nonmechanical models of primate circumorbital morphology
Authors: Ravosa Matthew J. 
Published: February 2006

AbstractLinear dimensions and angular orientations of the browridge, postorbital bar, and postorbital septum were obtained from a representative series of primates and compared with variables associated with several nonmechanical and biomechanical/mechanical models put forward to explain the form and function of the circumorbital region. Analyses of the results indicate that face size is the primary determinant of variation in primate circumorbital morphology. Anteroposterior browridge thickness is correlated with neural–orbital disjunction among anthropoid primates, but not among prosimians. This difference appears related to differences in the construction of the upper face and anterior cranial fossa between prosimians and anthropoids. Little support is demonstrated for the anterior dental loading model of browridge development. Mediolateral postorbital bar width and (to a lesser degree) browridge height are correlated with neurofacial torsion during mastication and variation in masticatory muscle size. These analyses further suggest that since circumorbital structures (especially the browridges) are located the farthest away from the chewing apparatus, they are least affected by masticatory stresses.
Modern human origins in Australasia: Replacement or evolution?
Authors: Kramer Andrew 
Published: February 2006

AbstractThe controversies surrounding the origins of modern humans have spawned two competing hypotheses, namely Replacement and Multiregional Evolution. The first suggests that modern Homo sapiens evolved first in Africa, as late as 140 ka, and subsequently inhabited the balance of the Old World. Conversely, the second hypothesis posits that modern humans evolved principally from local populations of archaic hominids indigenous to the major regions of the Old World.The hominid mandibular remains (ca. 1 Ma) from Sangiran, central Java, Indonesia, were studied in order to test these hypotheses. Non‐metric comparisons were performed between these fossils and aboriginal H. sapiens from Africa and Australia. The Replacement model would be supported by a unique Afro‐Australian grouping while Multiregional Evolution would be suggested by a Sangiran‐Australasian group which would exclude the modern Africans.These data support the Multiregional Evolution hypothesis in that a plurality (eight) of the seventeen non‐metric features link Sangiran to modern Australians, while only three exclusively group the humans from Africa and Australia. These results are suggestive of morphological continuity, which implies the presence of a genetic continuum in Australasia dating back at least one million years.
Mechanical implications of chimpanzee positional behavior
Authors: Hunt Kevin D. 
Published: February 2006

AbstractMechanical hypotheses concerning the function of chimpanzee anatomical specializations are examined in light of recent positional behavior data. Arm‐hanging was the only common chimpanzee positional behavior that required full abduction of the humerus, and vertical climbing was the only distinctive chimpanzee positional behavior that required forceful retraction of the humerus and flexion of the elbow. Some elements of the chimpanzee anatomy, including an abductible humerus, a broad thorax, a cone‐shaped torso, and a long, narrow scapula, are hypothesized to be a coadapted functional complex that reduces muscle action and structural fatigue during arm‐hanging. Large muscles that retract the humerus (latissimus dorsi and probably sternocostal pectoralis major and posterior deltoid) and flex the elbow (biceps brachii, probably brachialis and brachioradialis) are argued to be adaptations to vertical climbing alone. A large ulnar excursion of the manus and long, curved metacarpals and phalanges are interpreted as adaptations to gripping vertical weight‐bearing structures during vertical climbing and arm‐hanging. A short torso, an iliac origin of the latissimus dorsi, and large muscles for arm‐raising (caudal serratus, teres minor, cranial trapezius, and probably anterior deltoid and clavicular pectoralis major) are interpreted as adaptations to both climbing and unimanual suspension.
Relations between sex hormone level and characters of hair and skin in healthy young men
Authors: Knussmann Rainer , Christiansen Kerrin , Kannmacher Joachim 
Published: February 2006

AbstractTotal testosterone and dihydrotestosterone in blood serum as well as free testosterone in saliva were determined by radioimmunoassay in 110 healthy young men. The results were compared with the development of terminal hair on the trunk and limbs, with the disposition to balding and with the disposition to acne. No significant correlations were found between terminal hair development and absolute androgen levels; however, some significant values were observed in the case of the metabolic rate of dihydrotestosterone/testosterone and the proportion of free to total testosterone. The disposition to balding also correlates positively with the latter ratio. Yet the absolute serum androgen concentrations in men with a disposition to balding is lower than in men with no reduction of scalp hair. The widespread assumption that androgen levels are in general elevated in bald‐trait men must therefore be rejected. In accordance with this finding, men with a disposition to balding are morphologically (with regard to anthropometric measures) no more masculine than those with good scalp hair growth. When body build and age are taken into consideration, the relations between terminal hair and androgen ratio are also problematical. No relationship could be found between acne and androgens. © 1992 Wiley‐Liss, Inc.
Dental and cranial affinities among populations of East Asia and the pacific: The basic populations in East Asia, IV
Authors: Hanihara Tsunehiko 
Published: February 2006

AbstractThe origins of the four major geographical groups recognized as Australomelanesians, Micronesians, Polynesians, and East and Southeast Asians are still far from obvious. The earliest arrivals in Sahulland may have migrated from Sundaland about 40,000–50,000 years B.P. and begun the Australomelanesian lineage. The aboriginal populations in Southeast Asia may have originated in the tropical rain forest of Sundaland, and their direct descendants may be the modern Dayaks of Borneo and Negritos of Luzon. These populations, the so‐called “Proto‐Malays,” are possible representatives of the lineage leading to not only modern Southeast Asians, but also the Neolithic Jomon populations in Japan. The present study suggests, moreover, that the Polynesians and western Micronesians have closer affinities with modern Southeast Asians than with Melanesians or Jomonese. © 1992 Wiley‐Liss, Inc.
Negritos, Australian Aborigines, and the “proto‐sundadont” dental pattern: The basic populations in East Asia, V
Authors: Hanihara Tsunehiko 
Published: February 2006

AbstractFive evolutionarily significant dental traits were identified from a B‐square distance analysis of nine crown characters recorded for several populations of East Asia and Oceania. Intergroup variation in these traits distinguishes three major divisions of the Mongoloid dental complex: sundadonty, sinodonty, and the dental pattern of Australian Aborigines. The Australian crown features may be characterized as having high frequencies of evolutionarily conservative characters. Negritos, one of the probable representatives of indigenous inhabitants of Southeast Asia who may have shared a common ancestor with Australians, possess the more derived sundadont dental pattern. As far as the five crown traits treated here are concerned, Australian dental features may be described as conforming to a “proto‐sundadont” dental pattern, applying Turner's terminology. This pattern may represent a microevolutionary step prior to the emergence of the sundadont and sinodont patterns. © 1992 Wiley‐Liss, Inc.
Positional behavior and body size of arboreal primates: A theoretical framework for field studies and an illustration of its application
Authors: Cant John G. H. 
Published: February 2006

AbstractThe rationale for most field studies of the positional behavior of arboreal primates has been the need to document natural behaviors quantitatively in order to infer the functional significance of morphological configurations. This focus on interactions of morphology with behavior is justifiable, but there exists another important level of biological relationships, that of the animal with its structural habitat, which it must negotiate to find food and avoid being preyed on. Recently it has become apparent that body size is likely to affect relationships of positional behavior with habitat structure, as well as with morphology. Here I offer a framework for research on functional relationships of positional behavior, body size, and habitat structure, with the ultimate objective of elucidating the aptive significance of the great diversity exhibited by arboreal primates. This approach specifies several distinct problems that animals solve, and indicates how research might be directed at revealing the relative effectiveness with which different primates solve them. A preliminary application of the framework examines sympatric north Sumatran primates. © 1992 Wiley‐Liss, Inc.
Effects of demographic and ethnohistorical factors on average heterozygosities of South Amerindians
Authors: Aguiar Gilberto F. Souza 
Published: February 2006

AbstractRecent investigations have shown that average within‐Tupi genetic distances differ from within‐Carib distances, which is possibly due to differences in effective size of the populations belonging to these two linguistic stocks of South American tribes. The aim of this paper is to verify the influence of demographic factors and of interpopulation contacts on the degree of intragroup genetic variability of 18 South American native groups (eight Carib, seven Tupi, and three Gě). The mean per locus per individual heterozygosity (Hm) was studied for seven polymorphic systems and the distance from the centroid, rii on Hm was evaluated with regression analysis according to Harpending and Ward's model. Data on intergroup contacts among the populations since the end of the eighteenth century were collected from an extensive review of the ethnohistorical literature. The level of Hm of the three linguistic stocks did not differ; which suggests a homogeneous within‐group variation for these groups. In addition, there was no association between gene diversity and population size. On the other hand, demographic size correlated with rii, which suggest that gene frequencies in groups of larger populations more closely resemble the average gene frequencies of native South Americans. Values of rii differed between the stocks, and the average distance from the centroid of the Carib was about 2.6 times greater than that of the Tupi, in accordance with previous genetic distance analysis. It should also be emphasized that there was an important correlation between mean heterozygosity and the degree of historical intertribal contacts. This constitutes a particularly significant finding, suggesting the basic role of intertribal gene flow of the past to centuries on the level of present genetic variability of south American tribes. © 1992 Wiley‐Liss, Inc.
Muscle force recruitment and biomechanical modeling: An analysis of masseter muscle function during mastication in Macaca fascicularis
Authors: Hylander William L. , Johnson Kirk R. , Crompton A. W. 
Published: February 2006

AbstractThe main purpose of this study is to test the hypothesis that as subjects chew with increasing levels of force, the ratio of the working‐ to balancing‐side jaw‐muscle force (W/B) decreases and begins to approach 1.0. We did this by analyzing relative masseter force in Macaca fascicularis using both strain gage and surface electromyographic (EMG) techniques. In addition, we also analyzed: 1) the relationship between jaw position using cineradiographic techniques and relative masseter force, 2) the timing differences between relative masseter force from the working and balancing sides, and 3) the loading and unloading characteristics of the masseter muscle.Our findings indicate that when macaques increase the amount of overall masticatory force during chewing, the W/B ratio for masseter force frequently (but not always) decreases and begins to approach 1.0. Therefore, our working hypothesis is not completely supported because the W/B ratio does not decrease with increasing levels of force in all subjects. The data also demonstrate timing differences in masseter force. During apple‐skin mastication, the average peak masseter force on the working side occurs immediately at or slightly after the initial occurrence of maximum intercuspatiori, whereas the average peak masseter force on the balancing side occurs well before maximum intercuspation. On average, we found that peak force from the balancing‐side masseter precedes the working‐side masseter by about 26 msec. The greater the asynchrony between working‐ and balancing‐side masseter force, the greater the difference in the relative magnitude of these forces. For example, in the subject with the greatest asynchrony, the balancing‐side masseter had already fallen to about one‐half of peak force when the working‐side masseter reached peak force.Our data also indicate that the loading and unloading characteristics of the masseter differ between the working and balancing sides. Loading (from 50 to 100% of peak force) and unloading (from 100 to 50% of peak force) for the balancing‐side masseter tends to be rather symmetrical. In contrast, the working‐side masseter takes much longer to load from 50 to 100% of peak force than it does to unload from 100 to 50% of peak force. Finally, it takes on average about 35 msec for the working‐side zygoma and 42 msec for the balancing‐side zygoma to unload from 100 to 50% of peak force during apple‐skin mastication, indicating that the unloading characteristics of the macaque masseter during mastication closely approximates its relaxation characteristics (as determined by muscle stimulation). © 1992 Wiley‐Liss, Inc.
Systematics and body size: Implications for feeding adaptations in new world monkeys
Authors: Ford Susan M. , Davis Lesa C. 
Published: February 2006

AbstractThe relationship between body size and feeding ecology is well established for primates. It is argued that the evolutionary history of modern New World monkeys and, in particular, the path to attainment of current body size is significant in understanding the similarities and differences between dietary strategies and other ecological parameters of similar‐sized monkeys. Current interpretations of New World monkey evolutionary relationships are reviewed. Based on a synthesis of available body weights and the assumption that the earliest New World monkeys weighed close to 1 kg, similar to modern Aotus and Callicebus, predicted patterns of body size change in each lineage are given. Restrictions on directions of body size change in primates are discussed, and it is shown that “Stanley's Rule” offers a good explanation for differing body size ranges in New and Old World anthropoids. Predicted ecological correlates to body size drawn from the mammalian literature are offered and tested using data on New World monkeys, which show some concurrence and several interesting departures from predicted patterns. Sexual dimorphism in body weight of New World monkey species is reviewed, based on the new summary of body weight data given. © 1992 Wiley‐Liss, Inc.
Vertical clinging, small body size, and the evolution of feeding adaptations in the Callitrichinae
Authors: Garber Paul A. 
Published: February 2006

AbstractPrimates of the subfamily Callitrichinae (Callimico, Callithrix, Leontopithecus, and Saguinus) are small‐bodied New World monkeys (105–700 g) possessing clawlike nails on all manual and pedal digits excluding the hallux. Specialized nails in these genera serve a critical function in feeding by enabling tamarins and marmosets to cling to trunks and other large vertical supports while exploiting food resources. Within the subfamily, there is evidence of at least four distinct large‐branch feeding patterns. These include (1) seasonal exudate feeding and occasional trunk foraging (many Saguinus spp.); (2) exploitation of bark surface insects and the use of trunks as a platform to locate terrestrial prey (Saguinus fuscicollis, S. nigricollis, and Callimico); (3) manipulative foraging and bark stripping to locate concealed insects and small vertebrates (Leontopithecus); and (4) tree gouging and year‐round exudate feeding (many Callithrix). Large‐branch feeding and the use of vertical clinging postures appear to be a primary adaptation among virtually all callitrichines, distinguishing them ecologically from other platyrrhine taxa. Given the anatomy and behavior of extant callitrichines, Saguinus appears to be the most ecologically generalized member of this subfamily, and species of this genus may provide useful models for reconstructing the feeding and foraging adaptations of early callitrichines. © 1992 Wiley‐Liss, inc.
Morphological and behavioral adaptations for foraging in generalist primates: The case of the cebines
Authors: Janson Charles H. , Boinski Sue 
Published: February 2006

AbstractIn addition to being frugivorous, Cebus and Saimiri stand out among the New World primates of similar body size in being heavily dependent on animal matter for protein (faunivory). A detailed description of the morphology and behavior of the two genera is presented with the object of evaluating the interaction and respective contributions of morphological and behavioral adaptations to foraging patterns. Our conclusions include the following: First, body size is extremely important in explaining the observed variation in diet. Second, the emphasis on faunivory is facilitated more by behavioral than by morphological specialization. Third, whatever morphological specializations are present, particularly in Cebus, are probably favored by diet at the most food‐depauperate time of year. Fourth, although morphology may well reveal what a primate may potentially eat, to map this potential onto actual diet requires a detailed knowledge of its natural ecosystem. Finally, we consider whether the behavioral data support the tenuous morphological evidence for grouping Cebus and Saimiri within the clade Cebinae. © 1992 Wiley‐Liss, Inc.
Dermatoglyphic variation among Finno‐Ugric speaking populations: Methodological alternatives
Authors: Jantz R. L. , Brehme H. , Eriksson A. W. 
Published: February 2006

AbstractUtilization of dermatoglyphics for population studies is apparently increasing, but methods vary widely among investigators. We investigate how different types of dermatoglyphic data can affect estimates of biological distance among Finno‐Ugric speaking populations. Dermatoglyphic distances were calculated using the following categories of traits: 1) Finger ridge‐counts (radial and ulnar count for each digit), 2) finger ridge‐counts (largest count for each digit), 3) finger pattern types, 4) palm ridge‐counts, 5) palm patterns, and 6) main‐line terminations. In addition, we compare our distances with those of Heet, which rely heavily on summary characters. Distances are evaluated by comparing them to each other and to language and geographic distances.There is considerable variation in the pattern of relationships resulting from the different variable sets. Finger variables, whether ridge‐counts or pattern classifications, agree well with each other. Palm patterns, main‐lines, and finger variables show moderate agreement with each other, while palm ridge‐counts agree poorly with all variable sets except main‐lines. Heet's distances agree poorly with all other dermatoglyphic distances. Finger patterns and main‐lines are most closely related to language distances, after controlling for geography, while correlations with geography generally disappear after controlling for language. Heet's distances have weak associations with language and geography. Finger variables and palm main‐lines yield results which agree best with historical relationships among Finno‐Ugric populations. Our results make it very clear that utilization of dermatoglyphics in population studies requires careful consideration of methods, and that summary measures of quantitative or qualitative data should be used with caution. © 1992 Wiley‐Liss, Inc.
Can we really walk straight?
Authors: Uetake Teruo 
Published: February 2006

AbstractTwenty healthy men were asked to walk as straight as possible to a target 60 m away at normal speed. A series of footprints was recorded for each subject by having him wear socks soaked with red ink and walk on white paper fixed flat to the floor. Fourier analysis was applied to determine whether the subjects actually were able to walk straight, and the results revealed that all walked in a sinuous line rather than a straight line. Periodicity and amplitude of the meandering differed from subject to subject. These facts suggest that none of us can walk in a strictly straight line; rather, we meander, primarily due to a slight structural or functional imbalance of our limbs, which produces a gait asymmetry, and secondarily due to feedback from our sense of sight, which acts to correct the shifted walking course. © 1992 Wiley‐Liss, Inc.
Influence of teeth, alveoli, and periodontal ligaments on torsional rigidity in human mandibles
Authors: Daegling David J. , Ravosa Matthew J. , Johnson Kirk R. , Hylander William L. 
Published: February 2006

AbstractWe investigated the influence of teeth, periodontal ligaments, and alveoli on the structural integrity of human mandibles loaded in torsion. Surface bone strain was recorded from the mandibular corpus below the first molar on each of four specimens. These specimens were loaded by an external force that caused primarily torsion about the long axis of the corpus, and bone strain was recorded under the following conditions: 1) all supporting structures intact, 2) all supporting structures intact and the M1 loaded by a simulated bite force, 3) M1 removed and 4) alveolar bone of the M1 removed. For comparative purposes, experiments were also designed to investigate the effects of intermittent holes on the torsional rigidity of a baboon femur. This permitted comparison of the mechanical behavior of the mandibles with that of a more homogeneous bony member. These experiments suggest that the presence of teeth within alveoli has a measurable role in the maintenance of torsional rigidity. The condition of the periodontal ligament also appears to influence these stress‐bearing capabilities. Moreover, the alveolar bone supporting the teeth also provides structural support for countering torsional loads. For the specific case of corpus twisting, the mandible does not behave as a member with open or closed sections as predicted by theoretical models. The observed magnitudes of bone strain, however, conform more closely to the Predictions generated by a closed‐section model. © 1992 Wiley‐Liss, Inc.