Quantifying Ship Shape in Archaeology: Evaluating 3D Geometric Morphometrics

The analysis of the archaeological remains of ships and boats, in particular hull shapes, have been central to wider analysis of performance, function, and significance within past societies. This article reviews established methods of quantifying shape in ship and boat archaeology—linear measurement ratios and form coefficients—and evaluates the utility of 3D geometric morphometrics (GM). The 3D shape of 30 vessels from north‐west Europe dating between 325 BC and AD 1915 are quantified to study how hull shape relates to a vessel's function and intended operating environment. A comparison of the three methods highlights the importance of analysing the complexity of a hull in a holistic manner and demonstrates that 3D GM outperforms the traditional methods.     

Cranial shape variation and phylogenetic relationships of extinct and extant Old World leaf-nosed bats

Wilson, L.A.B., Hand, S.J., López-Aguirre, C., Archer, M., Black, K.H., Beck, R.M.D., Armstrong, K.N. & Wroe, S., July 2016. Cranial shape variation and phylogenetic relationships of extinct and extant Old World leaf-nosed bats. Alcheringa 40, 509–524. ISSN 0311-5518

The leaf-nosed bats in Hipposideridae and Rhinonycteridae currently have an Old World tropical to subtropical distribution, with a fossil record extending back to the middle Eocene of Europe. The Riversleigh World Heritage fossil site in northwestern Queensland constitutes a particularly rich archive of faunal diversity for Old World leaf-nosed bats, having yielded more than 20 species. We used 2D geometric morphometrics to quantify cranial shape in hipposiderids and rhinonycterids, with the aim of referring unallocated fossil species, particularly from Riversleigh, to each family within a phylogenetic framework, and using a quantitative approach to reconstruct cranial shape for key clades in these Old World radiations. Our sample comprised 21 extant hipposiderids and rhinonycterids, 1 megadermatid and 1 rhinolophid, in which 31 landmarks were placed in lateral and ventral views, and five measurements were taken in dorsal view. The phylogeny used as the framework for this study was based on an analysis of 64 discrete morphological characters from the dentition, cranium and postcranium scored for 42 extant and fossil hipposiderids and rhinonycterids and five outgroup taxa (rhinolophids and megadermatids). The phylogenetic analysis was conducted using maximum parsimony, with relationships among selected extant taxa constrained to match the results of recent comprehensive molecular studies. Our phylogenetic results suggest that the Riversleigh leaf-nosed bats probably do not represent an endemic Australian radiation, with fossil species spread throughout the tree and several with sister-group relationships with non-Australian taxa. Discriminant analyses (DA) conducted separately on each dataset resulted in cross-validated classification success ranging from 61.9% for ventral landmarks to 71.4% for lateral landmarks. Classification of the original grouped cases resulted in success of 81% for each dataset. Of the eight fossil taxa included as unknowns in the DA, six were found to be assigned to the same group as recovered by the phylogenetic analysis. From our results, we assign the Riversleigh Miocene species Archerops annectens, Brachipposideros watsoni, Brevipalatus mcculloughi, Rhinonicteris tedfordi and Xenorhinos halli to Rhinonycteridae, and Riversleigha williamsi and Hipposideros bernardsigei to Hipposideridae. Our results support Pseudorhinolophus bouziguensis, from the early Miocene of Bouzigues in southern France, as belonging to Hipposideridae, and probably Hipposideros. The reconstructed ancestor of hipposiderids was distinguished from that of the rhinonycterids by having a shorter rostrum, and less of a distinction between the rostrum and braincase.

Laura A.B. Wilson [laura.wilson@unsw.edu.au], Suzanne J. Hand [s.hand@unsw.edu.au], Camilo López-Aguirre [c.lopez-aguirre@unsw.edu.au], Michael Archer [m.archer@unsw.edu.au] and Karen H. Black [k.black@unsw.edu.au], PANGEA Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, NSW 2052; Robin M.D. Beck [r.m.d.beck@salford.ac.uk], School of Environmental & Life Sciences, University of Salford, Salford M5 4WT, UK; Kyle N. Armstrong* [kyle.armstrong@adelaide.edu.au], Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia. *Also affiliated with South Australian Museum, North Terrace, Adelaide, SA 5000, Australia; Stephen Wroe [swroe@une.edu.au], School of Environmental and Rural Science, University of New England, Armidale NSW 2351, Australia.     

A crossbeam co-ordinate caliper for the morphometric analysis of lithic nuclei: a description,test and empirical examples of application

Over the last four decades, there has been surprisingly little advance in the quantitative morphometric analysis of Palaeolithic stone tools, especially compared to that which has taken place in biological morphometrics over a comparable time frame. In Palaeolithic archaeology's sister discipline of palaeoanthropology, detailed quantitative morphometric, geometric morphometric, and even 3D geometric morphometric analyses are now seen almost as routine. This period of relative methodological stasis may have been influenced by the lack of homologous landmarks on many lithic tools (essential for any comparative analysis), especially core-based technologies of the Lower Palaeolithic. Archaeological field conditions may also prohibit the use of expensive and delicate precision instruments in certain cases. Here we present a crossbeam co-ordinate caliper that – crucially – both geometrically locates and measures distances between morphologically homologous landmarks upon lithic nuclei via a single protocol. Intra- and inter-observer error tests provide evidence that error levels associated with the instrument fall within acceptable ranges. In addition, we present empirical examples of application in the form of a multivariate analysis of 55 discrete morphometric variables, and a 3D geometric morphometric analysis of co-ordinate landmark configurations derived from Pleistocene lithic nuclei (i.e. ‘cores’ sensu lato). We also introduce to lithic studies some techniques for the study of shape variation that have previously been used with success in biological morphometric analyses. We conclude that use of an instrument such as the crossbeam co-ordinate caliper may provide a useful adjunct to traditional techniques of lithic analysis, particularly in developing a quantitative morphometric approach.     

The prevalence of,and the relationship between some spinal diseases in a human skeletal population from London

The prevalence of osteoarthritis, osteophytosis, intervertebral disc disease and diffuse idiopathic skeletal hyperostosis (DISH) was determined in a group of skeletons excavated from the crypt of Christ Church, Spitalfields. Age-specific prevalence rates were calculated from the group of skeletons for which age at death was known from intact coffin plates. Osteoarthritis of the facet joints occurred most frequently in the cervical and upper thoracic regions and was also common in the lower lumbar spine. The disease was more frequently bilateral in the lumbar spine than in upper regions. Osteophytes were common in the thoracic and lumbar spines, whereas intervertebral disc disease was confined almost completely to the cervical region. Diffuse idiopathic skeletal hyperostosis seemed to be underrepresented in this group, but was more common in males than in females. Age correlated significantly with all the conditions except DISH. Multiple regression analysis was carried out using each of the conditions as the dependent variable in turn. Age accounted for more of the variance than any of the other conditions added as independent variables.     

A geometric morphometrics-based assessment of blade shape differences among Paleoindian projectile point types from western North America

Blade shape features in the type definitions of Clovis, Folsom, and Plainview projectile points. However, the accuracy of these assessments has never been evaluated. Here we report a study in which geometric morphometrics and multivariate statistics were used to compare the shapes of the blades of Clovis, Folsom and Plainview points from the Southern Plains of North America. In the course of the analyses, we controlled for the impact of three potential confounding factors: allometry, differences in raw material quality, and resharpening. The analyses show that blade shape distinguishes Clovis points from both Folsom points and Plainview points, but does not distinguish Folsom points from Plainview points. The analyses also show that the similarities and differences in blade shape among the types are independent of allometry, raw material quality, and resharpening. These findings suggest that the type definitions for Clovis, Folsom and Plainview need to be altered. They also have implications for typing specimens that lack other defining characters (e.g. channel flakes, flutes). Lastly, the absence of resharpening effects raises questions about the validity of the reduction thesis.     

In sickness or in health? Assessment of Early Iron Age human skeletons from Toutswe sites,east central Botswana

The general health of Early Iron Age (AD 700 to 1300) mixed farmers in east central Botswana has not been studied before. In this study the bones and teeth of 84 individuals from ten Toutswe sites were analysed for osteological manifestations of disease, with the aim of assessing the general health of the Toutswe communities. These individuals were aged between newborn and 75 years old, and include both sexes. Results indicate the presence of diseases commonly found in archaeological populations such as osteoarthritis, spina bifida occulta, cribra orbitalia, porotic hyperostosis and enamel hypoplasias. One possible case of DISH was found. The frequency of lesions was comparable with or even lower than at other similar sites, such as K2 and Mapungubwe and other parts of southern Africa. The samples represent communities with relatively low levels of stress and infections. This seems to support the results of the palaeodemographic analysis, which indicated that the Toutswe people were better off than those of neighbouring K2 and Mapungubwe. Copyright © 2008 John Wiley & Sons, Ltd.     

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.     

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.