Temporal variation in prehistoric Nubian crania

Much of the earlier work on the prehistory of Sudanese Nubia has emphasized discontinuity between early Nubian populations. However, recent investigations suggest the converse - that a remarkable degree of cultural and biological continuity exists among indigenous Nubian groups, perhaps as far back as the Paleolithic. Thus, cultural and biological differences between Nubian populations can be most effectively perceived as the result of in situ evolutionary development. The present analysis has two major purposes: (1) to describe the morphological differences in the craniofacial complex between indigenous Nubian populations extending from the A-Group (c. 3,400 B.C.) through the Christian (c. 1,500 A.D.) horizons; and (2) to account for these differences within an evolutionary framework. The multiple discriminant analysis of radiographically derived variables revealed a trend from a substantially lower and more elongated cranial vault to a shorter and taller vault throughout the almost 5,000 year time span. Associated with this pattern was a tendency for the face to become more inferiorly-posteriorly located with respect to the vault in the latter groups. Finally, the masseter and temporalis muscles underwent a reduction and slight relocation through time. We speculate that this trend may be associated with behavioral changes associated with transition from a hunting and gathering to a totally agricultural subsistence pattern.     

Molar enamel thickness in the chacma baboon, Papio ursinus (Kerr 1792)

Modern humans exhibit increasing relative enamel thickness from M1 to M3. Some biomechanical (basic lever) models predict that the more distal molars in humans encounter higher occlusal forces, and it has been postulated that this provides a functional explanation for the observed gradient in relative enamel thickness. However, constrained three-dimensional models and experimental observations suggest that there is a reduction in bite force potential from M1 to M3, which would be consistent with the tendency for humans to reduce the size of the distal molars. In this regard, it has been postulated that the distal increase in enamel thickness is a consequence of crown size reduction; thus, it is unnecessary to invoke functional scenarios to explain this phenomenon. We assess these competing proposals by examining relative enamel thickness in a catarrhine primate (Papio ursinus) that exhibits crown size increase from M1 to M3. The molar row of P. ursinus is positioned relatively far forward of the temporomandibular joint, which results in the baboon being able to exert relatively greater muscle forces during posterior biting in comparison to modern humans. Thus, a significant distalward gradient of increasing enamel thickness would be expected in P. ursinus according to the hypothesis that posits it to be functionally related to bite force. The present study reveals no significant difference in relative enamel thickness along the molar row in P. ursinus. This finding lends support to the notion that the relatively thicker enamel of human distal molars is related primarily to their reduction in size. This carries potential implications for the interpretation of enamel thickness in phylogenetic reconstructions: the relatively thick molar enamel shared by modern humans and some of our fossil relatives may not be strictly homologous, in that it may result from different underlying developmental mechanisms.     

Biomechanical association of dental and temporomandibular pathology in a medieval Nubian population

An analysis of the relationship between oral pathology and degenerative change at the temporomandibular joint (TMJ) was undertaken on an archaeological sample of 122 adult crania from the Medieval site of Kulubnarti in Sudanese Nubia. The crania were sorted into 2 groups: those demonstrating clearly visible bony changes at the joint (TMJ+) and those without visible change (TMJ-). These groups were compared according to 1) age; 2) sex; 3) active dental pathologies (abscesses, caries, partial socket resorption); 4) tooth loss with complete socket resorption; and 5) dental attrition. No statistically significant association was evident between degenerative change at the TMJ and age, active dental pathologies, or dental attrition; however, sex differences and posterior tooth loss with complete socket resorption revealed a significant correspondence to degenerative TMJ changes. Both of these factors agree with the clinical literature and with biomechanical models (most notably that of Hylander) based upon modern populations. Furthermore, the results support the contention that paleopathological conditions can be analyzed from a clinical and functional biomechanical perspective.     

The molecular genetics of crop domestication

Ten thousand years ago human societies around the globe began to transition from hunting and gathering to agriculture. By 4000 years ago, ancient peoples had completed the domestication of all major crop species upon which human survival is dependent, including rice, wheat, and maize. Recent research has begun to reveal the genes responsible for this agricultural revolution. The list of genes to date tentatively suggests that diverse plant developmental pathways were the targets of Neolithic "genetic tinkering," and we are now closer to understanding how plant development was redirected to meet the needs of a hungry world.     

Inferring the Demographic History of African Farmers and Pygmy Hunter–Gatherers Using a Multilocus Resequencing Data Set

The transition from hunting and gathering to farming involved a major cultural innovation that has spread rapidly over most of the globe in the last ten millennia. In sub-Saharan Africa, hunter–gatherers have begun to shift toward an agriculture-based lifestyle over the last 5,000 years. Only a few populations still base their mode of subsistence on hunting and gathering. The Pygmies are considered to be the largest group of mobile hunter–gatherers of Africa. They dwell in equatorial rainforests and are characterized by their short mean stature. However, little is known about the chronology of the demographic events—size changes, population splits, and gene flow—ultimately giving rise to contemporary Pygmy (Western and Eastern) groups and neighboring agricultural populations. We studied the branching history of Pygmy hunter–gatherers and agricultural populations from Africa and estimated separation times and gene flow between these populations. We resequenced 24 independent noncoding regions across the genome, corresponding to a total of ~33 kb per individual, in 236 samples from seven Pygmy and five agricultural populations dispersed over the African continent. We used simulation-based inference to identify the historical model best fitting our data. The model identified included the early divergence of the ancestors of Pygmy hunter–gatherers and farming populations ~60,000 years ago, followed by a split of the Pygmies' ancestors into the Western and Eastern Pygmy groups ~20,000 years ago. Our findings increase knowledge of the history of the peopling of the African continent in a region lacking archaeological data. An appreciation of the demographic and adaptive history of African populations with different modes of subsistence should improve our understanding of the influence of human lifestyles on genome diversity.     

Neolithic transition and dental changes: the case of an Italian site

This paper compares the dentition of two samples of populations which lived in the same sites of Western Liguria (Italy) during the late phases of a hunting and gathering economy and at the beginning of agriculture respectively. The characteristics considered include metrics, pathology and wear. The older sample dates back to the Late Epigravettian (X-IX millennium B.C.), while the group of early farmers belongs mostly to the Middle Neolithic (IV millennium B.C.).The Neolithic group, conforming to the trend generally observed in human populations after the development of agriculture, shows reduction in crown size, spread of caries, increase in enamel hypoplasia, slower rates of wear on posterior teeth and less use of the anterior part of the dentition. Economic, technological, and dietary differences can provide a coherent explanatory model for the observed results. The possibility of biological relationships between the two samples is discussed with reference to archeological data.     

Cultural determinants of population stability in the Havasupai Indians

The Havasupai are a small tribe who have traditionally practiced very productive agriculture in a highly fertile, well-watered canyon. The agricultural subsistence base was formerly supplemented by hunting and gathering in adjacent areas which before significant American encroachment were plentifully supplied with desired game and wild vegetal products. Under these circumstances it would be expected that the tribe would be characterized by an expanding population. However, the population has been stable throughout historic times, approximately 200 years. In order to determine the significant factors responsible for the maintenance of population stability, all available information regarding Havasupai fertility, morbidity, mortality, and emigration was examined. An analysis of these data indicates that the population balance has been maintained primarily through cultural practices which limit fertility. Among the most important of these practices are the age at marriage, the age span differential between spouses, the high number of unmarried adults to be found in the population at any given time, the spermatocidal effect of the steam lodge, and perhaps the practice of infanticide and induced abortion.     

Post-pleistocene reductions in human dental structure: a reappraisal in terms of increasing population density

This paper discusses the well-documented acceleration which occurred in the reduction of human dental structure during the post-Pleistocene. It suggests that the process can be explained in terms of different but related factors inherent in a transition from late-Pleistocene hunting and gathering conditions to ones involving a sedentary life in larger groups. It is postulated that directional selective forces acting during Upper Paleolithic to maintain large tooth size had only a poor influence and that the new techniques in food preparation had little or no effect. The phenomenon is seen as a possible side-effect of a more complex overall reduction in body size, of which dental reduction only represents a small but demonstrable part. It is also suggested that stresses may have played an important role in producing a transitory reduced dimensional expression of the genetic background. An interaction between the variables directly or indirectly affecting body mass is shown in the model proposed which relates to post-Pleistocene. An increase in population density is indicated as being the most decisive biological factor in determining the acceleration in the trend towards reduction. A preliminary version of this paper was presented at the Symposium on Upper Paleolithic/Mesolithic of Europe and the Mediterranean Basin, Pisa, September 8–10, 1984.     

Remodeling of the temporomandibular joint following mandibular distraction osteogenesis in the transverse dimension

Transverse mandibular distraction osteogenesis involves moving the osteotomized segments of the mandible in either a varus or valgus direction. This maneuver allows for widening of the bigonial distance or for a lateral shift of an asymmetric mandibular midline. During this process, a significant amount of torque is placed on the mandibular condyles, because they act as the pivot point for the mandibular translation. Although standard linear distraction osteogenesis induces transient, reversible changes in the temporomandibular joint, it is not known what effect the varus and valgus stresses of transverse distraction have on the temporomandibular joint. We therefore designed a study to document the temporomandibular joint changes following various degrees of transverse distraction.Bilateral transverse mandibular distraction was performed on 10 adult, female mongrel dogs using an external, multiplanar mandibular distraction device. The distraction protocol was as follows: (1) complete osteotomy at the angle of the mandible, (2) 5-day latency period, (3) distraction rate of 1 mm/day, (4) rhythm of one turn per day, (5) linear activation 16 to 30 mm bilaterally, and (6) 8-week consolidation period. A variety of varus and valgus distraction vectors were applied to the mandible only after 10 mm of initial linear distraction had been achieved. Posteroanterior and lateral cephalograms were performed throughout the entire process. Pre-distraction and post-consolidation computed tomographic scans were also performed. Changes in mandibular conformation, axis of rotation, temporomandibular joint structure, and glenoid fossa changes were directly assessed by evaluating the postmortem craniofacial skeleton. The findings were compared with those of normal, age-matched mongrel dog skulls.Significant remodeling changes were observed in the temporomandibular joints of all animals involved in the study. The mandibular condyles demonstrated varying degrees of flattening and erosion at all contact points with the craniofacial skeleton. In some cases, the condyle became part of the distraction regenerate process and was hypertrophied in all dimensions. The condyles were frequently displaced out of the glenoid fossa, particularly on the side in the direction of varus distraction. When the latter occurred, a new fossa was created on the undersurface of the zygomatic arch. Varying degrees of mandibular rotation in the sagittal plane were also observed, which led to abnormal torquing of the condyles in the coronal plane, depending on whether the axis of rotation occurred primarily around the condyle or around the distraction regenerate zone.In conclusion, transverse mandibular distraction is an effective means of producing a varus or valgus shift in the gonion relative to the midsagittal plane. However, unlike linear or angular mandibular distraction, transverse distraction has a multitude of nontransient effects on the temporomandibular joint. Therefore it must be emphasized that in clinical practice, transverse distraction should be used cautiously. One must also be aware that such a maneuver in distraction can have negative effects on the temporomandibular joint.     

Histological study of the temporomandibular joint capsule: theory of the articular complex.

The findings of the histological study of the human temporomandibular joint confirm that the cranium and the lower jaw are jointed by two temporomandibular articular complexes (one on the left and another on the right side), each made up, in turn, of two joints--a condylomeniscal condyloarthrosis and a reciprocally fitting meniscotemporal joint. Both these joints are surrounded by short capsular bands which stretch from the condyle to the meniscus and from the latter to the temporal bone and form the true joint capsules. Longer bands which extend from the condyle to the temporal bone may be regarded as reinforcements passing over two articulations.     

Duiker demography and dispersal under hunting in Northern Congo

Duikers are the most heavily hunted species across forested Central and West Africa. Although these species form a vital food resource for people, little is known about their ecology and demography. The information available to date was collected from populations protected from hunting. However, hunting can profoundly alter demography and behaviour, such as dispersal, which in turn determine the sustainability of harvest. To address this research gap, I used radiotelemetry to examine duiker demography under hunting in Congo-Brazzaville. Among blue duikers ( Philantoba monticola , n = 17) I found annual survival rates (0.94), immature dispersal rates (0.25), and average home ranges (5.5 ha) that largely coincided with previous research from unhunted regions. Neighbouring animals all showed some home range overlap, in contrast to previous studies which found blue duikers to be strictly territorial. Although limited by sample size, immature animals' dispersal distances were relatively high (1.5 km, n = 2). Animals' dispersal rates do not appear to be greatly increased by hunting pressure, although source-sink theory depends upon high rates of dispersal to maintain the elevated and localized hunting offtakes observed around settlements. Building a fuller understanding of duiker demography under hunting, including dispersal, will be essential for conservation and management efforts.     

Hunting and Gathering in Tropical Rain Forest: Is It Possible?

Hunters and gatherers living in tropical forests represent an important part of the total range of variation among contemporary hunting and gathering societies. Studies of tropical forest hunting and gathering peoples have contributed to our perceptions of the foraging way of life. Yet no peoples have ever been directly observed living independently of agriculture in tropical rain forest. This article tests the hypothesis that humans do not exist nor have ever existed independently of agriculture in tropical rain forest. We find no convincing ethnographic evidence and, with the possible exception of Malaysia, no archeological evidence for pure foragers in undisturbed tropical rain forests. Negative evidence cannot be conclusive, but it suggests that we need to carefully reexamine common assumptions concerning the recent history of tropical forest dwellers, the adaptability of preagricultural humans, the geographic and environmental range of hominids, and the form and consequences of selection pressures acting on humans in warm, humid environments. The overriding purpose of this article is to stimulate further ecological and archeological research in the neglected tropical forest areas of the world.     

Population viability analysis of a Japanese black bear population

A population viability analysis (PVA) was conducted for a Japanese black bear population in Shimokita Peninsula, northern Japan, using an individual-based simulation model. Demographic stochasticity was incorporated in the model as well as the environmental stochasticity from the fluctuation of annual mast production. The extinction risk of the population was estimated with an emphasis on the effect of carrying capacity reduction and hunting pressure. The results suggest that the population has a high risk of extinction. Even if there is no further reduction of the carrying capacity and no hunting at all, the present size of the population cannot pass the test of the minimum viable population size (MVP) concept. Considering possible carrying capacity reduction in the future and actual hunting pressure, the population will fail to survive for 100 years at a very high probability. Because of deterioration of habitat and loss of the corridor between habitat areas, the population has become very sensitive to demographic impacts, including hunting pressure. Received: March 31, 1999 / Accepted: February 10, 2000     

Creation of a nature reserve, its effects on hunting management and waterfowl distribution in the Camargue (southern France)

The eastern portion of the Camargue in southern France is divided into two parts: a natural wetland area of 2800 ha and an agricultural area of 5045 ha. In 1984 and 1989, a new protected area (1000 ha) was created on two contiguous former hunting estates. Analysis of aerial photographs (1968–1998) in conjunction with a field survey revealed, from 1984 to 1998, an increase of management for waterfowl hunting in natural wetlands located on the periphery of the new reserve, and a similar increase in the agricultural area amongst residual wetlands and former rice fields. Based on monthly aerial censuses, the size of the waterfowl population in the winter increased in this part of the delta by a factor of 3.8 following the creation of the reserve. Our results suggest that the creation of a reserve on former hunting estates resulted in greater attractiveness for ducks but also in the development of commercial hunting activity around the edge. This development increased fragmentation and uniformity of natural areas, including the loss of the unique Cladium mariscus habitat in the Camargue and resulted in the spatial expansion of waterfowl hunting areas in agricultural areas. It is associated with an increase in financial profit from waterfowl hunting. Our study highlights unexpected costs for nature conservation associated with the creation of a reserve. It illustrates the need for new models of wetland conservation where protection goals are not restricted to reserves, but also integrate conservation and economic development outside the protected areas.     

Nontimber forest product gathering in Ritigala forest (Sri Lanka): Household strategies and community differentiation

Sri Lanka has a long tradition of forest product use. The relationship of people with a dry zone forest was studied using a sample of 48 households in two villages that varied in distance to the forest and access to the market. All households interviewed collected subsistence forest products and a majority of them also collected commercial products. The daily peak-season income from commercial gathering was 4.5 to 7.7 times the daily labor wage. There is a strong gender specialization, with commercial gathering dominated by men whereas subsistence gathering is almost exclusively the task of women. The average forest-derived household income in the village closer to the forest and with better market access was nearly double that of the other village. Family size as a proxy of labor availability was the main discriminating factor between those households who did and those who did not gather commercial products. A small inverse relationship between forest gathering and size of household agricultural land (particularly paddy rice) was observed. No clear relationship was found between total household income and forest derived income, contradicting the view that commercial forest gathering is an exclusive activity of the poorest households.     

Evidence of reactive oxygen species generation in synovial fluid from patients with temporomandibular disease by electron spin resonance spectroscopy

Reactive oxygen species (ROS) have been implicated in the pathogenesis of temporomandibular disorders. In the present study, we provide the first evidence of ROS generation in the synovial fluid from human temporomandibular disorder patients, as shown by electron spin resonance (ESR) and spin trapping. Three distinct ESR spectra of DMPO spin adducts were observed in the synovial fluid. They corresponded to three free radical species: hydroxyl radical (HO(*)), hydrogen radical (H(*)), and carbon-center radical (R(*)). Among them, the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO)-OH spectrum was the most prominent, suggesting that HO(*) was dominantly generated in the synovial fluid from temporomandibular disorder patients. Desferrioxamine (DFO), an iron chelator, strongly depressed the DMPO-OH signal intensity in the synovial fluid from patients with temporomandibular disorders. We successfully demonstrated ROS-induced oxidative stress in the synovial fluid from temporomandibular disorder patients. ROS generation in the temporomandibular joint could lead to exacerbation of inflammation and activation of cartilage matrix degrading enzymes that proceed to degenerative change of the temporomandibular joint. Thus, iron-dependent generation of HO( *) might have a crucial role in the pathogenesis of temporomandibular disorders.     

An Elephant in the Room: Okavango Safari Hunting as Ecotourism?

Safari hunters’ acute awareness of the widely held negative perceptions of their practice has led to their development of strong justifications and defensive assertions in favour of hunting. Far from being a primarily destructive practice, they claim that safari hunting in the Okavango Delta, Botswana, can be seen as an exemplary form of ecotourism, which benefits local communities, facilitates environmental conservation and provides the ultimate nature experience for participants. While research supports their claims to an extent, the ethical quandaries evinced by hunters themselves, the complex dialectic between local and global controls, and the elite, racialised and gendered nature of hunting speaks to a more complex and conflicted situation.     

Obstetric dimensions of the true pelvis in a medieval population from Sudanese Nubia.

Functional analysis of the true pelvis (defined as that portion lying below and including the pelvic brim) was undertaken on a sample of 36 females from the Medieval site of Kulubnarti in Sudanese Nubia. Standard obstetric measurements were taken and compared to four additional prehistoric skeletal samples and to modern American standards for the same obstetric dimensions. Relative to the other prehistoric populations, the Kulubnarti pelves are smaller in most dimensions and, when compared to modern American standards, from one-third to one-half would be diagnosed as contracted in one or more planes. Given the meager, fluctuating resources of these Medieval Nubians' harsh desert environment, pelvic size reduction is a likely result of body size reduction as one biological response to nutritional stress (Mittler and Van Gerven, 1989; Moore et al., 1986; Van Gerven et al., 1981). It is argued, however, that size reduction created a high potential for either maternal-neonatal morbidity and mortality due to fetopelvic disproportion or neonatal loss due to low birth weight. In either case, it is suggested that the Kulubnarti population paid a significant biological price for this aspect of size reduction.