American Journal of Physical Anthropology

doi: 10.1002/ajpa.1330490318pmid: N/A

doi: 10.1002/ajpa.1330490301pmid: N/A

Gershowitz, Henry; Neel, James V.

doi: 10.1002/ajpa.1330490302pmid: 727233

The Gm and Km immunoglobulin allotypes are presented, for the first time, for six South American Indian tribes (Baniwa, Kanamari, Kraho, Makiritare, Panoa, and Ticuna) and one Central American tribe (Guaymi). Additional allotype information is presented for five previously reported South American tribes (Cayapo, Piaroa, Trio, Xavante and Yanomama). The distributions of the Gm and Km allotypes among all the tribal populations tested to date are reviewed and evidence is presented for the presence of a north (high) ‐south (low) cline in Km frequency. The wave theory of the populating of the South American continent was tested by an examination of the distribution of six alleles (Gmax;g, Gma;b0,3,t, Dia, Rz, TFD Chi, and 6PGDC), absent in some populations but with polymorphic proportions in others. The present, limited, data failed to confirm the theory.

Jungers, William L.

doi: 10.1002/ajpa.1330490303pmid: N/A

Slow vertical climbing and clinging are the dominant positional behaviors of the most convincing reconstruction of the primary spatial niche of Megaladapis, a giant extinct prosimian from Madagascar. The vertical support model of Cartmill ('74) predicts that clawless mammals should exhibit relatively elongated forelimbs in expanded size ranges. The allometric corollaries of this model are tested on closely related interspecific samples of Megaladapis and selected extant prosimians. Megaladapis and indriids (vertical leapers and clingers) conform to the structural predictions of the model, and are clearly distinguished from the more pronograde lemurids and cheirogaleids. Extreme hindlimb reduction (negative allometry) is coupled with moderate forelimb elongation (positive allometry) in Megaladapis. These body proportions effectively optimize pedal friction during vertical climbing and minimize the moment of body weight pulling the animal away from the trunk. Positive forelimb allometry occurs in the indriids, while isometry obtains for the hindlimb. The adaptive significance of these morphological strategies are discussed, as are possible selective mechanisms which effect the extreme hindlimb reduction in Megaladapis. Body weight estimates are also presented for Megaladapis edwardsi and Megaladapis grandidieri (50–100 kg and 40–75 kg, respectively).

Trinkaus, Erik

doi: 10.1002/ajpa.1330490304pmid: 727234

The use of non‐metric skeletal traits to compute population distance statistics assumes strong genetic control of trait expression. An investigation of bilateral asymmetry frequencies of human cranial and postcranial non‐metric traits shows that asymmetry is common. This suggests that environmental stress, as well as the genotype, is important in controlling trait frequencies.

Jayakar, S. D.; Marcovina, S.; Peracino, A.; Siccardi, A. G.

doi: 10.1002/ajpa.1330490305pmid: 310247

Data on serum protein levels in Binga Pygmies are presented, and these are compared with the levels in healthy Italians and in Italians suffering from liver diseases. Principal Component Analysis carried out on the three groups points out similarities in protein levels between the Pygmies and the Italian Hepatopaths on one hand and between healthy and liver diseased Italians on the other. Discriminant Analyses reveal the important differences between the populations. It is suggested that such analyses of protein levels could serve as tools in population biology.

Sirianni, J. E.; van Ness, A. L.

doi: 10.1002/ajpa.1330490306pmid: 103436

Postnatal growth of the cranial base was longitudinally studied in 21 male and 11 female Macaca nemestrina. The basicranium of each animal was marked with tantulum implants in order that the tracings of each serial roentgenogram could be superimposed. Between the ages of 3.0 and 5.0 years the degree of sexual demorphism in both angular and linear dimensions increased. The cranial base flattened as a result of the upward and forward migration of nasion and the upward and backward relocation of basion. The movement of basion was primarily due to differential growth recorded at the sphenooccipital synchondrosis. Sexual difference in the relative growth of this synchondrosis resulted in a longer and somewhat flatter male cranial base. Male and female velocity curves showed accelerations that coincide with their estimated age for the onset of puberty.

Smith, Richard J.

doi: 10.1002/ajpa.1330490307pmid: 103437

There is disagreement as to whether the mandibular condyles are stress‐bearing or stress‐free during mastication. In support of alternative models, analogies have been drawn with Class III levers, links, and couple systems. Physiological data are reviewed which indicate that maximum masticatory forces are generated when maxillary and mandibular teeth are in contact, and that this phase lasts for over 100 msec during many chewing strokes. During this period, the mandible can be modeled as a beam with multiple supports. Equations of simple beam theory suggest that large condylar reaction forces are present during mastication. With unilateral molar biting in man, the total condylar reaction force may be over 75% of the bite force. Analysis of a frontal projection demonstrates that up to 80% of the total condylar reaction force is borne by the contralateral (balancing side) condyle during unilateral molar biting. A comparison of human, chimpanzee (P. troglodytes), spider monkey (A. belzebuth), and macaque (Macaca sp.) morphology indicates that the frugivorous chimpanzee and spider monkey have a relatively lower condylar reaction force than the omnivorous macaque or man during molar biting. The percentage reaction force during incisal biting is lower in man than in the other primates, and lower in the frugivorous primates than in the macaque.

Baume, Robert M.; Crawford, M. H.

doi: 10.1002/ajpa.1330490308pmid: 727235

Seven hundred dental casts from four Tlaxcaltecan Indian populations of Mexico were analyzed for the incidence of ten discrete dental traits. The populations are of known historical origin, with Cuanalan and Saltillo transplanted from the Valley of Tlaxcala approximately 400 years ago. Given this temporal and geographical separation of these transplanted populations from the parental gene pool, statistically significant morphological divergence was observed. However, varying degrees of admixture with Spanish and possibly African colonists have complicated the interpretation of the results. Shovelling of incisors was shown to be the best discriminator of group differences. Mandibular molar patterns and mandibular incisor extension indicate that Cuanalan is closest to Saltillo while the valley communities, Tlaxcala and San Pablo, are closest to each other.

Turner, Christy G.; Swindler, Daris R.

doi: 10.1002/ajpa.1330490309pmid: 727236

The dental crown morphology and size of 48 male West Nakanai, New Britain, Melanesians is described and compared with other Pacific and Asian dental samples. The West Nakanai dentition is like those of other Melanesians, much less like those of Polynesians and Micronesians, and very dissimilar to teeth of modern and Neolithic Southeast Asians. It is suggested that the origin of the modern Melanesian dental pattern (large but simplified teeth) was probably in Melanesia, not Southeast Asia as the orthodox view of a Hoabinhian‐Australmelanesian relation claims.