Cruel traces: bone surface modifications and their relevance to forensic science

The reconstruction of perimortem and postmortem events is of critical importance to criminal investigations. In many cases, the information required for these reconstructions can be accessed through the analysis of skeletal remains. One particular class of skeletal data—trauma to the surfaces of bones, or bone surface modifications (BSMs)—can reveal much about the perimortem and postmortem intervals. While the study of BSMs originated within the fields of paleontology and archeology and was only later integrated into forensic science, a fruitful interdisciplinary exchange of data and methods is now commonplace. BSMs from thermal alteration, sharp-force trauma, terrestrial and aquatic scavengers and predators, bacteria and fungi, insects, weathering, and sediment abrasion can supply investigators with valuable information about the agents and events of a corpse's deposition, including weapon type, local environmental conditions, the postmortem interval, and the presence, temperature(s), and/or length(s) of thermal exposure. Based on a review of this rich body of literature, we argue that (a) all associations between a BSM and its alleged source must rest on observational cause-and-effect studies; (b) secure identifications of BSMs should rely both on the intrinsic features of the modifications themselves and relevant contextual data; (c) the scientific validity of BSM research depends, ultimately, on rigorous blind-testing and the establishment of error rates; and (d) researchers need to make a concerted effort to enhance interanalyst correspondence through objective definitions, measurements, and/or codes of BSM features. The most promising path forward lies in the combination of digital image analysis and multivariate predictive modeling

An Introduction to Zooarchaeology

zooarchaeology is a self-reproducing field taught in many university departments of anthropology or archaeology. As archaeologists have literally taken faunal analysis into their own hands, they have debated how best to use animal remains to study everything from early hominin hunting or scavenging to animal production in ancient market economies. Animal remains from archaeological sites have been used to infer three kinds of information: the age of deposits (chronology); paleoenvironment and paleoecological relations among humans and other species; human choices and actions related to use of animals as food and raw materials. Methods for reconstructing human diet and behavior have undergone the greatest growth over the last four decades, and most of this book addresses the second and third areas. This book deals with what I know best: vertebrate zooarchaeology, and within that, analysis of mammalian bones and teeth

Paleovegetation and stone tool use at a selection of hominin sites and their associated landscapes from Olduvai Gorge (Tanzania): a study of plant microfossils

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Geografía e Historia, leída el 18-11-2016Esta tesis doctoral presenta los resultados de una serie de análisis multidisciplinares que tienen como objeto los microfósiles de plantas. Los objetivos de la tesis fueron mejorar las identificaciones gránulos de almidón mediante el uso de un sistema automatizado, evaluar las muestras modernas como método de inferencia a través del estudio de fitolitos de suelos y plantas relacionadas con áreas húmedas en África, y la reconstrucción del paleoambiente/paleopaisaje de dos yacimientos de la garganta de Olduvai para analizar su influencia en el comportamiento de los homínidos. Para mejorar la identificación de gránulos de almidón se utilizó un sistema de análisis de imagen que midió 123 caracteres ópticos y morfológicos de aproximadamente 5000 gránulos de 20 especies de plantas comestibles del este de África. Los datos obtenidos se analizaron mediante un sistema estadístico de aprendizaje automático (Random Forest). Los resultados muestran que, a pesar de que el sistema desarrollado no es perfecto, es más eficaz que las identificaciones de visu, cuyo acierto medio fue del 25% frente al 53% del sistema automatizado. Se observó que el sistema es sensible al número de especies analizadas y, en un menor grado, al número de caracteres utilizados, por lo que consideramos que reducir las potenciales especies a identificar es crucial para obtener identificaciones precisas y para ello es necesario combinar diversos análisis. De no ser así la identificación automática de gránulos de almidón no será lo suficientemente precisa para ser utilizada en arqueología. Para mejorar el conocimiento de los conjuntos de fitolitos que permitan obtener inferencias precisas de las muestras fósiles se analizaron los fitolitos de 22 suelos modernos provenientes del entorno de Olduvai y de 14 especies relacionadas con ambientes húmedos. Los resultados del análisis de suelos muestran que los fitolitos reflejan, parcialmente, la estructura vegetación, pero no el tipo de vegetación que los produjo y que las diferencias entre diferentes tipos de formaciones son sutiles. Sin embargo, se observó que dichas diferencias son apreciables cuando se aplican herramientas estadísticas...This thesis presents a series of multidisciplinary analysis using plant microfossils. The objectives of this thesis are to improve the identification of starch granules through the use of an automated system, to evaluate modern analogues as an inference method through the study of modern phytolith assemblages and the study of phytoliths from humid areas in Africa, to reconstruct the paleoenvironment/paleolandscape of two Olduvai sites and to analyze the influence of paleovegetation on hominid behavior. In order to improve the identification of starch granules, an image analysis program was used- a program capable of measuring up to 123 different optical and morphological characters in ~5000 starch granules of 20 different East African edible plant species. The data obtained were analyzed using a machine learning approach (Random Forest). The results show that this automated system is not perfect, but that it is still more powerful than the human eye, for which the average success rate is just 25% for species level identifications, as opposed to 53% for the automated system. In evaluating the performance of the system, I found that accuracy rates in the identification of starch granules are highly sensitive to the number of species being identified and, to a lesser extent, to the number of characters used by the identification system. It is therefore crucial to narrow down as much as possible the number of target species by analyzing additional proxies. If this is not done, the automated identification of starch granules will not be accurate enough to provide acceptable interpretations in archaeological contexts...Fac. de Geografía e HistoriaTRUEunpu

Addressing subjectivity in the classification of palaeoenvironmental remains with supervised deep learning convolutional neural networks

Archaeological object identifications have been traditionally undertaken through a comparative methodology where each artefact is identified through a subjective, interpretative act by a professional. Regarding palaeoenvironmental remains, this comparative methodology is given boundaries by using reference materials and codified sets of rules, but subjectivity is nevertheless present. The problem with this traditional archaeological methodology is that higher level of subjectivity in the identification of artefacts leads to inaccuracies, which then increases the potential for Type I and Type II errors in the testing of hypotheses. Reducing the subjectivity of archaeological identifications would improve the statistical power of archaeological analyses, which would subsequently lead to more impactful research. In this thesis, it is shown that the level of subjectivity in palaeoenvironmental research can be reduced by applying deep learning convolutional neural networks within an image recognition framework. The primary aim of the presented research is therefore to further the on-going paradigm shift in archaeology towards model-based object identifications, particularly within the realm of palaeoenvironmental remains. Although this thesis focuses on the identification of pollen grains and animal bones, with the latter being restricted to the astragalus of sheep and goats, there are wider implications for archaeology as these methods can easily be extended beyond pollen and animal remains. The previously published POLEN23E dataset is used as the pilot study of applying deep learning in pollen grain classification. In contrast, an image dataset of modern bones was compiled for the classification of sheep and goat astragali due to a complete lack of available bone image datasets and a double blind study with inexperienced and experienced zooarchaeologists was performed to have a benchmark to which image recognition models can be compared. In both classification tasks, the presented models outperform all previous formal modelling methods and only the best human analysts match the performance of the deep learning model in the sheep and goat astragalus separation task. Throughout the thesis, there is a specific focus on increasing trust in the models through the visualization of the models’ decision making and avenues of improvements to Grad-CAM are explored. This thesis makes an explicit case for the phasing out of the comparative methods in favour of a formal modelling framework within archaeology, especially in palaeoenvironmental object identification

Macro-faunal exploitation in the Cape Floral Region (Fynbos Biome) of the southern Cape, South Africa c. 75-60 ka: case studies from Blombos Cave and Klipdrift Shelter

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. 2016The analysis of faunal remains from archaeological sites can reveal much about past behaviour, palaeoenvironments and bone technology. This is especially pertinent for the Middle Stone Age (MSA): a period that corresponds to both the behavioural and anatomical development of Homo sapiens. In this thesis, I examine the faunal remains from Blombos Cave (BBC) and Klipdrift Shelter (KDS), two significant MSA sites about 45 km apart along the present-day southern Cape coast. The focus of the analyses is on the Still Bay (SB) layers (c. 75 – 68 thousand years ago [ka]) at BBC and the Howiesons Poort (HP) layers (c. 65 – 59 ka) at KDS. The aim of this thesis is to explore subsistence behaviour and environmental conditions during the SB and HP in the fynbos region of the southern Cape. I also investigate the effects of trampling on bone and whether trampling and other types of taphonomic modification can be used to infer occupational intensity in cave and rock shelter sites. Taphonomic data indicate that significant differences exist between the SB and HP faunal assemblages at BBC and KDS, respectively. Carnivores and scavengers had a greater effect on the SB than on the KDS assemblage. Furthermore, subsistence activities at KDS focused on marrow extraction while filleting was probably an important strategy at BBC. Taxonomic analyses indicate that the representative fauna from both sites is generally consistent with what is expected in the fynbos biome but with some noticeable differences. Grazers, for example, are significantly more prevalent at KDS than BBC while seal is more common at BBC. Other zooarchaeological data also show differences in prey selection strategies. Diet breadth is more extensive at KDS than at BBC, although bovid mortality profiles at BBC are more juvenile-dominated. I propose that many of these contrasting patterns imply that subsistence intensification is more evident in the HP layers at KDS than in the SB at BBC. Moreover, the taphonomic data suggest that the SB at BBC was a low-intensity, sporadically occupied period in contrast to the high-intensity occupations, particularly during the middle layers of the HP at KDS. The results of the KDS analysis also indicate a shift in environmental conditions during the HP and show links between prey selection, the environment and occupational intensity during this period. Trampling experiments indicate that trampling can generally be distinguished from butcherymarks, although bioturbation in shelly deposits can sometimes result in marks that mimic cutiii marks. More importantly, experiments show that pitting and abrasion are a more significant indicator of trampling than lines that resemble cut-marks. Based on these experiments, I argue that trampling modification can be used to infer occupational intensity at archaeological sites. Trampling marks in the KDS assemblage, for example, correspond well with the high occupational periods as indicated by other taphonomic data. Trampling and taphonomic data support the notion that BBC was a low-intensity, sporadically occupied site during the SB. By incorporating taxonomic, taphonomic and novel methods of skeletal-part analyses, this study contributes to our knowledge of human subsistence and palaeoenvironments during the SB and HP in the southern Cape. This thesis strengthens and adds to other research that has demonstrated variability in subsistence behaviour during the MSA.LG201

Estudio tafonómico y espacial del yacimiento DS del Lecho I de la garganta de Olduvai (Tanzania)

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Geografía e Historia, leída el 16-12-2020Faunal remains recovered at early archaeological sites dated to around 2 million years (Ma) play a critical role in discussions about the evolution of early hominin behavior. Anthropogenic assemblages from this time period are scarce, however and, until recently, most of the available evidence on the behavior of early Homo has been almost exclusively obtained at the FLK Zinj site from Bed I in Olduvai Gorge (Tanzania). The recent discovery of DS (David’s Site, 1.84 Ma) and two additional hominin-made accumulations on the same paleosurface as the iconic site of FLK Zinj provides an invaluable opportunity to address key issues regarding early hominin lifestyles, particularly their subsistence behaviors and their foraging capabilities. The DS site has been extensively excavated and is exceptionally well preserved. Over the past years, significant advances in taphonomic and spatial statistical techniques have been made, which mainly involve the combination of several variables in multivariate approaches and the use of machine learning algorithms. The application of these methods to the faunal fossil record within extended frames of reference helps overcome equifinality when trying to detect the main agent of site formation and interpret site function...Los restos faunísticos recuperados en algunos de los yacimientos arqueológicos más antiguos, que datan de alrededor de dos millones de años (Ma), desempeñan un papel muy importante en las discusiones sobre la evolución del comportamiento de los homininos. Sin embargo, los conjuntos arqueológicos de origen antrópico de ese periodo son escasos y, hasta hace poco, la mayor parte de los datos disponibles sobre el comportamiento de los primeros miembros del género Homo han sido obtenidos casi exclusivamente del yacimiento FLK Zinj del Lecho I de la Garganta de Olduvai (Tanzania). El reciente descubrimiento de DS (David’s Site, 1.84 Ma) y de otras dos acumulaciones generadas por homininos sobre la misma paleosuperficie que el emblemático yacimiento de FLK Zinj, brinda una valiosa oportunidad para abordar cuestiones clave relacionadas con la forma de vida de los primeros Homo con nuevos datos, en particular sus comportamientos de subsistencia y sus capacidades depredadoras. El yacimiento se ha excavado en extensión y se encuentra excepcionalmente bien preservado. A lo largo de los últimos años, se han realizado avances significativos en las herramientas tafonómicas y espaciales estadísticas disponibles, que ahora comprenden principalmente la combinación de varias variables en aproximaciones multivariantes y el uso de algoritmos de máquinas de aprendizaje automático. La aplicación de estos métodos al registro faunístico fósil y la utilización de marcos referenciales ampliados permite superar problemas de equifinalidad a la hora de detectar el agente principal de formación del yacimiento e interpretar la funcionalidad de la localidad...Fac. de Geografía e HistoriaTRUEunpu

A Critical Assessment of Sampling Biases in Geometric Morphometric Analysis: The Case of Homo erectus

This study primarily explores the potential of GMA in capturing and recognizing specific morphological features of specimens commonly allocated to H. erectus. For these purposes, four surface semilandmark datasets were collected for analyzing the gross morphology of the entire crania, posterior crania, temporal bones, and frontal bones. Results show that though dense surface semilandmarks can potentially capture many morphological features that cannot be included by using discrete landmarks, some shape differences visualized by PCA, include those in lateral cranial profiles, the trajectories of the squamosal sutures and the inclinations of the nuchal planes, do not match observed morphology. Procrustes superimposition is identified as an important, yet usually ignored, factor that may contribute to some incompatibilities between visualized shape differences and observed morphology. This is because Procrustes superimposition rotates configurations to different orientations to minimize their overall differences, while observed morphology is based on aligning specimens in the Frankfurt plane. This study also assesses three sampling issues associated with statistical analyses commonly used for testing whether H. erectus is too variable to be a single species based on landmark data. The first two are whether densities of semilandmarks and focusing on different cranial regions can yield inconsistent results of the same statistical analyses. The third is whether including a large sample of H. sapiens may affect results of PCAs. Results suggest that semilandmarks used in this study are oversampled, because using a much smaller number of semilandmarks can yield nearly identical results. The reason is that GMA places more weight on gross shape differences than details. Furthermore, the analyses of the temporal and frontal bones show results incompatible with those of the entire and posterior crania, likely because the former analyses focus on shapes of individual bones, while the latter analyses focus on gross cranial shapes. In addition, including a large sample of H. sapiens with fossils cause higher-ranked PCs to emphasize variations within H. sapiens. In this case, it is also important to examine lower PCs to understand shape differences between fossils

Humanity from African Naissance to Coming Millennia

Humanity From African Naissance to Coming Millennia arises out of the world's first Dual Congress that was held at Sun City (South Africa) in 1998 that refers to a conjoint, integrated meeting of two international scientific associations, the International Association for the Study of Human Palaeontology - IV Congress - and the International Association of Human Biologists. The volume includes 39 refereed papers covering a wide range of topics, from Human Biology, Human Evolution (Emerging Homo, Evolving Homo, Early Modern Humans), Dating, Taxonomy and Systematics, Diet, Brain Evolution, offering the most recent analyses and interpretations in different areas of evolutionary anthropology.Humanity From African Naissance to Coming Millennia arises out of the world's first Dual Congress that was held at Sun City (South Africa) in 1998 that refers to a conjoint, integrated meeting of two international scientific associations, the International Association for the Study of Human Palaeontology - IV Congress - and the International Association of Human Biologists. The volume includes 39 refereed papers covering a wide range of topics, from Human Biology, Human Evolution (Emerging Homo, Evolving Homo, Early Modern Humans), Dating, Taxonomy and Systematics, Diet, Brain Evolution, offering the most recent analyses and interpretations in different areas of evolutionary anthropology