Taxonomic Abundance at Panxian Dadong, a Middle Pleistocene Cave in South China

The faunal assemblage from the site of Panxian Dadong provides evidence for a general continuity in species representation throughout a period of approximately 120 kya. Taxonomically, faunal material from Dadong includes classic taxa of the Middle Pleistocene Ailuropoda-Stegodon faunal complex of South China. Taxonomic abundance measures document a sample that is rich in large ungulate species including rhinoceros, stegodonts, and large bovids. These data are further examined in light of assemblage formation processes, temporal distribution, and environmental context. Taphonomic data that demonstrate the presence and activities of bonecollecting species (including porcupines, hominids, and large and small carnivores) suggest that Dadong Cave was an attractive shelter that saw many uses during the period analyzed. These include hominid foraging, porcupine bone collecting, and carnivore scavenging and hunting. KEYWORDS: Middle Pleistocene, South China, Ailuropoda-Stegodon fauna, hominid

Lithic Raw Material Use at the Late Middle Pleistocene Site of Panxian Dadong

The possibility of selective use of lithic raw material in the Middle Pleistocene cave deposits of Panxian Dadong is examined in order to evaluate hominid strategies of resource management. Limestone, chert, and basalt, available in or nearby the cave, were differentially used for the production of tools and unretouched flakes. Limestone was predominantly used to produce expedient tools, unretouched flakes were most commonly made of basalt, and chert was most frequently used to produce retouched flakes and tools. Patterns in the reduction sequence for each raw material also indicate that these lithic resources were selectively used. The early stages of core reduction are clearly represented in basalt flakes, whereas chert artifacts exhibit the later stages of tool production and the greatest degree of resharpening. When the selection of raw material is examined through time, over a span of more than 100,000 years, two patterns are clear. The proportion of chert and basalt and the overall frequency of artifacts increases. These changes in the frequency and selection of raw material occur without a techno-typological change. The major shifts in raw material usage correlate with a colder climatic regime and may relate to the intensified use of the cave for animal carcass processing and shelter. KEYWORDS: Middle Pleistocene, lithics, reduction sequence, hominid

Third molar impaction and agenesis: influence on anterior crowding

Background Third molar influence on anterior crowding is controversial, but they are assumed to play a major role in compromising dental arch space. Aim To evaluate the relationship among impaction, agenesis and crowding in black South African males. Subjects and method Mandibles and maxillae of 535 black South African males in the Raymond A. Dart Collection of Human Skeletons, University of the Witwatersrand were examined for anterior crowding and third molar agenesis and impaction. Dental crowding was determined using Little’s irregularity index. Results Individuals with impaction showed more moderate-to-extreme crowding than those with agenesis. Bilateral third molar presence was more frequently associated with ideal-to-minimal crowding. Weak positive but significant correlations between crowding and impaction were found (mandible, ρ = 0.154, p = 0.000; maxilla ρ = 0.130, p = 0.000). The direction was the opposite for bilateral presence of molars (mandible, ρ = −0.135, p = 0.02; maxilla, ρ = −0.111, p = 0.010). Odds of mandibular crowding were greatest in individuals with impaction (OR = 3.22, CI = 1.716–6.05, p < 0.001). Maxillary results were similar. Conclusion Third molar impaction plays a role in anterior crowding. Third molar presence was not associated with anterior crowding, while agenesis did not explain absence of crowding

Three-dimensional geometric morphometric studies of modern human occipital variation.

ObjectivesTo investigate three-dimensional morphological variation of the occipital bone between sexes and among populations, to determine how ancestry, sex and size account for occipital shape variation and to describe the exact forms by which the differences are expressed.MethodsCT data for 214 modern crania of Asian, African and European ancestry were compared using 3D geometric morphometrics and multivariate statistics, including principal component analysis, Hotelling's T2 test, multivariate regression, ANOVA, and MANCOVA.ResultsSex differences in average occipital morphology are only observed in Europeans, with males exhibiting a pronounced inion. Significant ancestral differences are observed among all samples and are shared by males and females. Asian and African crania have smaller biasterionic breadths and flatter clivus angles compared to Europeans. Asian and European crania are similar in their nuchal and occipital plane proportions, nuchal and occipital angles, and lower inion positions compared to Africans. Centroid size significantly differs between sexes and among populations. The overall allometry, while significant, explains little of the shape variation. Larger occipital bones were associated with a more curved occipital plane, a pronounced inion, a narrower biasterionic breadth, a more flexed clivus, and a lower and relatively smaller foramen magnum.ConclusionsAlthough significant shape differences were observed among populations, it is not recommended to use occipital morphology in sex or population estimation as both factors explained little of the observed variance. Other factors, relating to function and the environment, are suggested to be greater contributors to occipital variation. For the same reason, it is also not recommended to use the occiput in phylogenetic studies

Is parity a cause of tooth loss? Perceptions of northern Nigerian Hausa women.

BACKGROUND:Reproduction affects the general health of women, especially when parity is high. The relationship between parity and oral health is not as clear, although it is a widespread customary belief that pregnancy results in tooth loss. Parity has been associated with tooth loss in some populations, but not in others. It is important to understand the perceptions of women regarding the association between parity and tooth loss as these beliefs may influence health behaviors during the reproductive years. AIM:To explore the views of Hausa women regarding the link between parity and tooth loss. METHODS:Qualitative data were collected through a grounded theory approach with focus group discussions (FGDs) of high and low parity Hausa women (n = 33) in northern Nigeria. Responses were elicited on the causes of tooth loss, effects of tooth loss on women's quality of life, issues of parity and tooth loss, and cultural beliefs about parity and tooth loss. The data were analyzed thematically using ATLAS-ti. RESULTS:Respondents associated tooth loss with vomiting during labor, a condition termed 'payar baka'. Poor oral hygiene, excessive consumption of refined carbohydrates, tooth worm, cancer and ageing were also believed to cause tooth loss. The greatest impacts of tooth loss on the lives of the respondents were esthetic and masticatory changes. CONCLUSION:Respondents perceived that parity is indirectly linked to tooth loss, as reflected in their views on the association between vomiting during labor and tooth loss

Panxian Dadong, South China: Establishing a Record of Middle Pleistocene Climatic Changes

Broad-based reconstructions of the Middle Pleistocene Asian environment are valuable sources of information that can augment our understanding of prehistoric human adaptations and expansion into East Asia. The sediments, speleothems, and geochronology of Panxian Dadong Cave serve as an example of the possible integration of this broader paleoenvironmental information with more fine-grained archaeological data. The current U-series and ESR dating results for Dadong suggest that the early human activity in the cave began at least 260 kya and continued until around 142 kya. This period correlates with Oxygen Isotope Stages 7 through 6. The lower part of the breccia (Layer 2) contains very strongly weathered dark deposits, suggesting a relatively warm climatic period from 260-180 kya that corresponds to OIS 7, followed by a cooler phase with less speleothem formation corresponding to OIS 6. The Middle Pleistocene stratigraphic sequence in the Dadong cave deposits documents fluctuating and rapid changes in temperature and humidity that are also detected in general Asian, as well as South China, paleoclimatic studies based on diverse data ranging from microstratigraphic and geochemical sediment analyses to mollusk species representation. KEYWORDS: Middle Pleistocene, Asian paleoenvironment, stratigraphy, speleothem, Panxian Dadong, China

Late Middle Pleistocene climate in southwestern China: inferences from the stratigraphic record of Panxian Dadong Cave, Guizhou

Panxian Dadong Cave, situated in the subtropical zone of southwestern China, preserves a fan-like sedimentary sequence close to its entrance that spans the period between MIS 8 and 5 (300–130 ka). The frequent alternation of flowstone formation, cementation, clastic deposition, and frost activity in the depositional sequence makes it ideal for reconstructing the environmental conditions prevailing during the later Middle Pleistocene on the Guizhou Plateau. Macroscopic and microscopic sedimentary analyses determine that clastic deposits were entering the cave in the form of intermittent cohesive debris flows and sheetflows during cold and relatively dry climatic conditions when vegetation cover was reduced. Interlayered impure flowstones were forming during wetter phases but still under glacial conditions. Seasonally freezing temperatures are deduced from the frequent occurrence of cycles of well-developed freeze–thaw features affecting both the clastic parts of the sequence and the flowstones as they were deposited. The described depositional processes were responsible for lateral redistribution on the fan surface of bone remains and lithic artifacts that were accumulating on the surface as a result of hominid activities. During the intervening interglacial stages (MIS 7 and possibly MIS 5) clastic deposition was considerably reduced and only thin flowstone caps and weathering manganese–iron crusts were forming. It is suggested that precipitation was much higher during glacial intervals than interglacials under a predominantly cold climate. Dadong Cave provides a good example of very cold and wet climatic conditions during glacials in the subtropics of East Asia