Assessing Collector Bias: A Geometric Morphometric Analysis of a Collection of Isolated Clovis Points from the Midcontinent

Clovis points are found across the contiguous United States as isolated surface finds and as elements of assemblages in surface and subsurface deposits. Despite being scattered over the continent, Clovis points exhibit a remarkable degree of standardization, yet there is still a demonstrable level of variation in their shapes across regions. Including isolated points in regional comparative analyses would significantly increase sample sizes and spatial coverage of these analyses; however, the effects of collector bias—the tendency to collect the most typical and aesthetically pleasing points—are unknown. Here, we examine the shape of a sample of isolated Clovis points from the midcontinent using geometric morphometric techniques. We show that resharpening had little effect on the shape of points and that our sample of isolated points are similar in shape to points from assemblages in the midcontinent. Our findings suggest that isolated points have research potential when collector bias is limited.     

Virtual anthropology and forensic arts: the facial reconstruction of Ferrante Gonzaga

In the last few years virtual anthropology has been used to solve different problems that could not be properly addressed using a traditional anthropological approach. Mainly when dealing with mummies or embalmed bodies, the virtual approach is the only solution to carry out a detailed analysis of the skeleton without jeopardizing the integrity of the physical remains.     

Subsistence and mobility strategies in the Epipalaeolithic: a stable isotope analysis of human and faunal remains at 'Uyun al-Hammam,northern Jordan

This paper investigates evidence for subsistence and settlement activities in the Levantine Middle Epipalaeolithic through the application of stable isotope analysis to human and non-human remains from the site of 'Uyun al-Hammam, northern Jordan. In general, bone from the site suffers a high degree of diagenesis and collagen could not be extracted for analysis here. Carbon and oxygen isotopic values from human tooth enamel samples were variable, but within expected values for the Middle Epipalaeolithic, whereas animal carbon and oxygen isotopic values varied widely, most likely due to hydrological and climatological factors. Carbon and isotopic values for the human samples indicated a predominantly C₃ plant dietary input, while animal samples appeared to have varying amounts of C₄ inputs into their diet. This is the first isotopic analysis conducted on material from the Middle Epipalaeolithic of the southern Levant and, as such, even results constrained by temporal and climatological variants within the region contribute to the overall knowledge of settlement and subsistence strategies during this cultural period.     

Faces of Homo floresiensis (LB1)

Since being excavated in 2003, the skull of LB1 (the holotype of Homo floresiensis) has been given many faces, though the details regarding how each was accomplished are typically few. Here we detail our application of known, and verified, relationships between the skull and soft tissues of anatomically modern humans to produce an evidence-based facial approximation of LB1. We then compare our results to nine pre-existing LB1 faces using geometric morphometrics. These analyses suggest our facial approximation differs in proportional facial width, upper lip height and nasal morphology. Some of these differences are likely due to a different interpretation of taphonomic and excavation damage, application of different 'forensic' methods and/or an idiosyncratic incorporation of aspects of non-human primate morphology. Other differences, and in particular upper lip height, are less justifiable in relation to the skeletal evidence.     

Discriminating Paleoindian point types from Florida using landmark geometric morphometrics

Traditional artifact typologies are typically poorly defined. While several attributes usually help define a “type,” shape is invariably the most important. Here I report on a study that uses landmark-based geometric morphometrics to better define three Paleoindian point types from Florida: Suwannees, Simpsons, and Transitional Side Notched. Bilaterally symmetric specimens were created from the original artifacts to capture the presumed ideational forms of the points. The shapes of the bases and the entire points were tested to determine whether the types could be discriminated, and if so which shape was best at discriminating the types. The results show that the base configurations were best at discriminating the groups in two different jackknife allocation tests. The entire point shape was less robust due to the variability in blade shape. The study demonstrates that the three point types can be rigorously defined in ways that are usable in daily archaeological practice, and that base shape, rather than the entire shape, is a better discriminator. Further, the study demonstrates the utility of using several freeware programs for processing and analyzing shape data.     

Can morphospace shed light on cave bear spatial-temporal variation? Population dynamics of Ursus spelaeus from Romualdova pe?ina and Vindija, (Croatia)

Cave bear (Ursus spelaeus) behavioural ecology, as evidenced through population dynamics, is crucial for improving our understanding of why this species went extinct. Despite the fact that the bones of this species have been recovered in very large quantities, allowing for extensive study, fundamental questions regarding its life-ways remain unanswered. We present research using geometric morphometrics (GMM) on molars to investigate population structure based on morphological variation over space and through time. This preliminary work deliberately restricts the geographic catchment area for sampling, allowing for a meaningful appraisal of scale of variation within a spatially conservative framework. Our results demonstrate no significant morphological variation evident temporally and a small but statistically significant degree of shape variation geographically despite the proximity of the study localities. These findings suggest that an accurate quantitative exploration of morphospace may be an important source of evidence on environmental and climatic shifts and the resulting influence on animal morphology.     

Numerical Characteristics of Explicit Method for Nonlinear Systems

Numerical properties of the Newmark explicit method in the solution of nonlinear systems are evaluated by introducing a parameter, which is named the instantaneous degree of nonlinearity, to monitor the variation of stiffness with time. Stability analysis reveals that the upper stability limit is inversely proportional to the square root of the instantaneous degree of nonlinearity and thus it is no longer equal to 2 for nonlinear systems. In fact, it is shrunk as instantaneous degree of nonlinearity is larger than 1 while it is enlarged as instantaneous degree of nonlinearity is less than 1. It is also proved that the satisfaction of stability limits for each time step implies a stable computation in the complete step-by-step integration procedure. Accuracy analysis shows that the relative period error is increased with the increase of the instantaneous degree of nonlinearity for a given product of the initial natural frequency and time step. Furthermore, a rough guideline is proposed for accurate integration of nonlinear systems and its appropriateness is confirmed with numerical examples.     

Optimal Spectral Acceleration-based Intensity Measure for Seismic Collapse Assessment of P-Delta Vulnerable Frame Structures

This study proposes an “optimal” spectral acceleration-based intensity measure (IM) to assess the collapse capacity of highly inelastic frame structures vulnerable to the P-delta effect. The IM is derived from the geometric mean of the spectral pseudo-acceleration over a certain period interval. The lower bound period of the averaging interval is related to the mode in which 95% of the effective modal mass is exceeded. The upper bound period is 1.6 times the fundamental period. This IM provides minimum, or close to the minimum, dispersion for frames with different fundamental periods of vibration, or number of stories.     

Uluburun shipwreck stowaway house mouse: molar shape analysis and indirect clues about the vessel's last journey

Human translocation by stowaway transport is the widely accepted vector of the current worldwide distribution of commensal rodents but its historical process has never been directly evidenced. The anecdotal find of the small murine (mice and rats) mandible among the wealthy cargo of the Uluburun shipwreck provide us with an unexpected opportunity to directly evidence the species associated with this stowaway and provide indirect clues regarding the ship's route. Taxonomic identification and geographic sourcing has been performed using outline molar shape analysis by Elliptic Fourier Transform comparing the Uluburun mouse molar phenotype with extant populations from eastern Mediterranean sibling species. Results showed that the mandible belonged to the house mouse (Mus musculus domesticus) with significant phenotypic similarities with extant Syrian house mouse populations. These results provide the earliest direct evidence for stowaway transports highlighting the historical process of the house mouse invasion of the Mediterranean. Using modern behavioural comparisons, combined with archaeological and historical sources, it has been argued that the servicing port of Ugarit (Minet el Beida) was a likely step on the vessel's last journey.