The significance of the fossil hominid skull from Petralona,Greece

Evidence is accumulating that the hominid cranium found in the Petralona cave in 1960 is associated with cave deposits of middle Pleistocene age. If this is so, the fossil is the most complete middle Pleistocene cranium yet discovered and provides important morphological, metrical and radiographic information on the possible evolutionary transition from Homo erectus to Homo sapiens. The classification of the specimen is discussed and it is suggested that a grade system within Homo spaiens should be erected. The Petralona fossil would be allocated to Homo sapiens grade 1 rather than to Homo erectus or to a subspecies of Homo sapiens.     

Craniofacial morphology,diet and incisor use in three native American populations

It has been difficult to infer behaviours related to anterior tooth use in fossil hominids owing to a lack of broad‐based comparative studies of the relationships between front tooth use and craniodental features in modern humans. In this study, we seek to establish such a neontological baseline by exploring aspects of craniodental form among populations of recent humans that are inferred to have differed in habitual levels of ingestive and paramasticatory processing using the incisors. Morphometric data are compared among samples from three human populations: Aleutian Islanders (n=25); Arikara from the Mobridge Site, SD (n=19); and a late Woodland Bluff group from Jersey County, IL (n=24). Data for various biomechanically relevant dimensions were collected using standard callipers, while three‐dimensional (3D) coordinate data for 28 cranial landmarks were recorded using a video‐based image analysis system. These data indicate that several aspects of cranial form thought to influence the efficiency of force production on the incisors differ among the examined groups, including the positions and size of the primary masticatory muscles and the position of the dentition. For most dimensions, the Aleut sample exhibits the most mechanically advantageous configuration, the Illinois Bluff group the least advantageous configuration, while the Arikara are intermediate in form. This pattern corresponds to differences in the intensity of incisor loading among these groups, as inferred from both ethnographic reports and incisor microwear data. These results, therefore, suggest that cranial form in humans varies with subsistence‐related differences in masticatory force production and that quantitative studies of masticatory system configuration may provide useful information for studies of hominid palaeobiology. Copyright © 2000 John Wiley & Sons, Ltd.     

Exploring the Relations Between Riverbank Erosion and Geomorphological Controls Using Geographically Weighted Logistic Regression

The relations between riverbank erosion and geomorphological variables that are thought to control or influence erosion are commonly modelled using regression. For a given river, a single regression model might befitted to data on erosion and its geomorphological controls obtained along the river's length. However, it is likely that the influence of some variables may vary with geographical location (i.e., distance upstream). For this reason, the spatially stationary regression model should be replaced with a non‐stationary equivalent. Geographically weighted regression (GWR) is a suitable choice. In this paper, GWR is extended to predict the binary presence or absence of erosion via the logistic model. This extended model was applied to data obtained from historical archives and a spatially intensive field survey of a length of 42 km of the Afon Dyfi in West Wales. The model parameters and the residual deviance of the model varied greatly with distance upstream. The practical implication of the result is that different management practices should be implemented at different locations along the river. Thus, the approach presented allowed inference of spatially varying management practice as a consequence of spatially varying geomorphological process.