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

Spatial analysis of an early middle palaeolithic kill/butchering site: the case of the cuesta de la bajada (Teruel, Spain)

Kill/butchering sites are some of the most important places for understanding the subsistence strategies of hunter-gatherer groups. However, these sites are not common in the archaeological record, and they have not been sufficiently analysed in order to know all their possible variability for ancient periods of the human evolution. In the present study, we have carried out the spatial analysis of the Early Middle Palaeolithic (MIS 9-8) site of Cuesta de la Bajada site (Teruel, Spain), which has been previously identified as a kill/butchering site through the taphonomic analysis of the faunal remains. Our results show that the spatial properties of the faunal and lithic tools distribution in levels CB2 and CB3 are well-preserved although the site is an open-air location. Both levels show a similar segregated (i.e. regular) spatial point pattern (SPP) which is different from the SPP identified at other sites with similar nature from the ethnographic and the archaeological records. However, although the archaeological materials have a regular distribution pattern, the lithic and faunal remains are positively associated, which is indicating that most parts of both types of materials were accumulated during the same occupation episodes, which were probably sporadic and focused on getting only few animal carcasses at a time.Post-Doc Xunta de Galicia Grant (ED481D-2022/023); ERC Consolidator grant (CoG—101045506).info:eu-repo/semantics/publishedVersio

Spilled ink blots the mind: A reply to Merrit et al. (2018) on subjectivity and bone surface modifications

Categorical variables identifying microscopic features of cut marks produce high accuracy in discrimination of bone surface modifications, but are vulnerable to variable degrees of inter-analyst subjectivity. Metric analyses of cut mark width and depth are presented by Merritt et al. (2018) as a more objective method of identifying cut marks. However, this uni(bi)variate method has shown very high rates of mark classification error when structurally similar marks are compared. Furthermore, within-sample comparison carried out via subsampling shows that different datasets of metric values, obtained with the same type of tool and raw material, are subject to such a high degree of variability that significant differences of homogeneous subsamples are repeatedly obtained, thus preventing any useful analogs to be made. Additionally, this much higher stochastic variability depends on limited knowledge of the contextual processes that intervene in cut mark metric properties, as well as on a mismatch between theoretical premises on the immanent-configurational process-trace dynamics and their confusion during experimental praxis. The selection of specific contextual variables and disregard of others, in addition to the combination of different tool types and raw materials, distorts the resulting cut mark properties. This indicates that even when attempting to use exclusively metric numeric variables, subjectivity is a conditioning factor in analyzing and interpreting cut marks

Tracing the spatial imprint of Oldowan technological behaviors: A view from DS (Bed I, Olduvai Gorge, Tanzania)

DS (David’s site) is one of the new archaeological sites documented in the same paleolandscape in which FLK 22 was deposited at about 1.85 Ma in Olduvai Gorge. Fieldwork in DS has unearthed the largest vertically-discrete archaeological horizon in the African Pleistocene, where a multi-cluster anthropogenic accumulation of fossil bones and stone tools has been identified. In this work we present the results of the techno-economic study of the lithic assemblage recovered from DS. We also explore the spatial magnitude of the technological behaviors documented at this spot using powerful spatial statistical tools to unravel correlations between the spatial distributional patterns of lithic categories. At DS, lavas and quartzite were involved in different technological processes. Volcanic materials, probably transported to this spot from a close source, were introduced in large numbers, including unmodified materials, and used in percussion activities and in a wide variety of reduction strategies. A number of volcanic products were subject to outward fluxes to other parts of the paleolandscape. In contrast, quartzite rocks were introduced in smaller numbers and might have been subject to a significantly more intense exploitation. The intra-site spatial analysis has shown that specialized areas cannot be identified, unmodified materials are not randomly distributed, percussion and knapping categories do not spatially overlap, while bipolar specimens show some sort of spatial correlation with percussion activities

En busca del primer Homo: gestión de la investigación arqueológica en la Garganta de Olduvai (Tanzania)

[EN] The sites at Olduvai Gorge (Tanzania) constitute a unique venue for the study of the first members of the genus Homo. The large amount of fossils recovered and the good state of preservation of these sites have boosted archaeological research in the Gorge throughout the years. The Olduvai Paleoanthropology and Paleoecology Project (TOPPP) research team, present at the Gorge since 2006, launched the construction of the Aguirre-Mturi Scientific Station within the limits of the Ngorongoro National Park with the aim of improving the working conditions and provide a safe working space. The safeguard of the archaeological materials was also one of the cornerstones during the design process and building of the station. The laboratory allows almost immediate cleaning, analysis and restoration of the materials recovered during field work. Meanwhile, in Spain, the Institute of Evolution in Africa (IDEA), current headquarters of the TOPPP team, was founded with the aim of promoting the study of African paleoanthropology and the origins of humankind in Africa. Along with the research work, TOPPP strives to bring the scientific knowledge to the general public in several ways, including the management of temporary and permanent exhibitions in Spain and Tanzania.[ES] Los yacimientos de la Garganta de Olduvai (Tanzania) constituyen un enclave único para el estudio de los primeros representantes del género Homo. La buena preservación de estos yacimientos y la cantidad de fósiles hallados en ellos posibilita que se sigan desarrollando excavaciones arqueológicas en este lugar. El equipo de investigación The Olduvai Paleoanthropology and Paleoecology Project (TOPPP), que trabaja en estos yacimientos desde 2006, promovió la construcción de la Estación Científica Aguirre-Mturi con el propósito de mejorar las condiciones laborales del personal investigador y de hacer del campamento un lugar seguro de trabajo. Durante el proceso de creación y construcción se tuvo en cuenta la salvaguarda de los materiales arqueológicos, y gracias a la existencia de un laboratorio en el campamento, es posible realizar tareas como la limpieza, el análisis y la restauración del material recuperado. En España, la creación del Instituto de Evolución en África (IDEA), sede actual del equipo TOPPP, nace con el objetivo de promover el estudio de la paleoantropología africana y el origen del ser humano en África. Junto a los trabajos de investigación, TOPPP realiza una intensa actividad divulgativa donde destaca la creación de exposiciones temporales y permanentes en España y Tanzania.A la Comisión para la Ciencia y la Tecnología (COSTECH), a la Autoridad del Área de Conservación del Ngorongoro (NCAA) y al Departamento de Antigüedades y al Ministerio de Turismo y Recursos Naturales en Tanzania por el permiso para investigar en la Garganta de Olduvai. Al Ministerio de Ciencia, Innovación y Universidades por el proyecto concedido (HAR2017-82463-C4-1-P) y por la financiación para los contratos predoctorales de Formación de Profesorado Universitario (FPU) de MVR y JA; al Ministerio de Cultura a través del Instituto de Patrimonio Cultural de España por las ayudadas concedidas para Proyectos Arqueológicos en el Exterior, y a la Fundación Palarq por las ayudas para apoyar las Misiones de Arqueología y Paleontología Españolas en el en el extranjero.Peer reviewe

Thrombectomy within 8 hours after symptom onset in ischemic stroke

BACKGROUND: We aimed to assess the safety and efficacy of thrombectomy for the treatment of stroke in a trial embedded within a population-based stroke reperfusion registry. METHODS: During a 2-year period at four centers in Catalonia, Spain, we randomly assigned 206 patients who could be treated within 8 hours after the onset of symptoms of acute ischemic stroke to receive either medical therapy (including intravenous alteplase when eligible) and endovascular therapy with the Solitaire stent retriever (thrombectomy group) or medical therapy alone (control group). All patients had confirmed proximal anterior circulation occlusion and the absence of a large infarct on neuroimaging. In all study patients, the use of alteplase either did not achieve revascularization or was contraindicated. The primary outcome was the severity of global disability at 90 days, as measured on the modified Rankin scale (ranging from 0 [no symptoms] to 6 [death]). Although the maximum planned sample size was 690, enrollment was halted early because of loss of equipoise after positive results for thrombectomy were reported from other similar trials. RESULTS Thrombectomy reduced the severity of disability over the range of the modified Rankin scale (adjusted odds ratio for improvement of 1 point, 1.7; 95% confidence interval [CI], 1.05 to 2.8) and led to higher rates of functional independence (a score of 0 to 2) at 90 days (43.7% vs. 28.2%; adjusted odds ratio, 2.1; 95% CI, 1.1 to 4.0). At 90 days, the rates of symptomatic intracranial hemorrhage were 1.9% in both the thrombectomy group and the control group (P = 1.00), and rates of death were 18.4% and 15.5%, respectively (P = 0.60). Registry data indicated that only eight patients who met the eligibility criteria were treated outside the trial at participating hospitals. CONCLUSIONS: Among patients with anterior circulation stroke who could be treated within 8 hours after symptom onset, stent retriever thrombectomy reduced the severity of post-stroke disability and increased the rate of functional independence

Early Pleistocene faunivorous hominins were not kleptoparasitic, and this impacted the evolution of human anatomy and socio-ecology

Humans are unique in their diet, physiology and socio-reproductive behavior compared to other primates. They are also unique in the ubiquitous adaptation to all biomes and habitats. From an evolutionary perspective, these trends seem to have started about two million years ago, coinciding with the emergence of encephalization, the reduction of the dental apparatus, the adoption of a fully terrestrial lifestyle, resulting in the emergence of the modern anatomical bauplan, the focalization of certain activities in the landscape, the use of stone tools, and the exit from Africa. It is in this period that clear taphonomic evidence of a switch in diet with respect to Pliocene hominins occurred, with the adoption of carnivory. Until now, the degree of carnivorism in early humans remained controversial. A persistent hypothesis is that hominins acquired meat irregularly (potentially as fallback food) and opportunistically through klepto-foraging. Here, we test this hypothesis and show, in contrast, that the butchery practices of early Pleistocene hominins (unveiled through systematic study of the patterning and intensity of cut marks on their prey) could not have resulted from having frequent secondary access to carcasses. We provide evidence of hominin primary access to animal resources and emphasize the role that meat played in their diets, their ecology and their anatomical evolution, ultimately resulting in the ecologically unrestricted terrestrial adaptation of our species. This has major implications to the evolution of human physiology and potentially for the evolution of the human brain

An archaeostratigraphic consideration of the Gran Dolina TD10.2 cultural sequence from a quantitative approach

Understanding the temporal resolution of archaeological deposits is a critical issue for drawing behavioural inferences. In the case of TD10.2 (Gran Dolina, Sierra de Atapuerca), this factor becomes essential in defining the mass communal bison hunting level and the different butchering events that took place at the sub-unit, which is characterised as a kill-butchering site. Traditionally, the dissection of events within an assemblage is performed by visual archaeostratigraphic techniques. This method, however, can be challenging in high-density sites without marked sterile gaps between levels. In this study, we present a combination of archaeostratigraphic techniques, supervised machine learning, and lithic refits applied to TD10.2. This integration of techniques offers a more automated and time-efficient archaeostratigraphic analysis, supports a more quantitative strand of evidence, and enables final verification using refits, even though it still requires prior visual archaeostratigraphic processing to set up qualitative data. Results have allowed for the definition of three distinct levels within the sub-unit along the entire excavation surface, highlighting the potential of these methods. Moreover, this approach facilitates the accurate delineation of level boundaries in the bison bone bed level, assessing its high spatiotemporal resolution, and identifying a minimum of two seasonal communal hunting events. This result reinforces previous interpretations while also providing new insights into the subsistence and behavioural strategies of the hominins that occupied the cavityThis research has been developed within the frame of the projects PID2021-122355NBC32 (MICINN-FEDER), SGR 2021-01239 (AGAUR) and 2022PFRURV-64 (URV). A. Arteaga-Brieba is the beneficiary of a predoctoral fellowship from Gobierno de Navarra/Nafarroako Gobernua. L.A. Courtenay is funded by the Spanish Ministry of Science, Innovation and Universities, with an FPI Predoctoral Grant (Ref. PRE 2019-089411), associated with the project RTI 2018-099850-B-I00 and the University of Salamanca. A. Rodríguez-Hidalgo is supported by the Spanish Ministry of Science and Innovation through the “María de Maeztu” (CEX2019-000945-M).Institut Catal a de Paleoecologia Humana i Evolucio Social (IPHES-CERCA) has received financial support from the Spanish Ministry of Science and Innovation through the “María de Maeztu” program for Units of Excellence (CEX 2019-000945-M).With funding from the Spanish government through the "Severo Ochoa Center of Excellence" accreditation CEX 2019-000945-M.Peer reviewe