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AIM: Human skeletal repositories are crucial resources for research and education in human biology, variation, anatomy, biocultural frameworks, forensic/medico-legal casework, heritage and understanding the past. In this review paper, we assess the composition of human skeletal repositories in South Africa, along with the ethical and legal frameworks that safeguard their curation. METHODS: The data and information pertaining to local human skeletal repositories were gathered through a combination of literature review and direct contact with local curators for information. Data pertaining to source origins, sample demographics, and temporal distribution (where applicable) were extracted and reporting trends across publications were assessed. RESULTS: South Africa has 12 main human skeletal repositories, six affiliated with universities and six with museums. There are over 12 300 human skeletal remains housed across these repositories, mainly of cadaveric, archaeological, forensic (medico-legal), and unknown origin. Universities are primarily stewards of large cadaveric collections (n = ± 6 200); however, a few manage archaeological (n = ± 1 300) and forensic repositories (n = ± 1 000). Museums exclusively curate repositories of archaeological origin and approximately ± 3 700 archaeological individuals can be found countrywide. CONCLUSIONS: The ethical challenges faced by South African repositories are deeply connected to the country's colonial and apartheid history. Concerns related to consent, autonomy, cultural sensitivity, data availability and the respectful treatment of the deceased, require constant attention and consideration. We highlight several initiatives undertaken to address these issues, including the implementation of new management approaches by repositories, a shift away from using unclaimed bodies, efforts in deaccessioning and repatriation and an increased focus on community engagement.
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This study investigates the desiccation process of soft-tissue in South Africa, analyzing its interaction with environmental parameters and its implications for estimating the post-mortem interval. Through the examination of four decomposing porcine bodies across two summer seasons and one winter season, the research quantifies desiccation patterns using custom-designed and constructed printed circuit boards to measure the moisture content of body tissue over time. Generalized additive models were used to determine the environmental forces driving desiccation. Tissue resistivity was tested against the environmental predictor variables to determine the amount of variation they account for, and predicted values of the region-specific tissue resistivity variables were measured for each decomposing body. Results reveal distinct desiccation trajectories between summer and winter, with summer conditions conducive to precocious natural mummification. Environmental factors, particularly temperature and solar radiation, emerge as significant drivers of desiccation. This study represents the first quantitative analysis of deep tissue desiccation internationally, but also the first quantitative assessment of desiccation and natural precocious mummification in the Western Cape, South Africa. The exploration of desiccation as a potential indicator for estimating PMI opens new avenues for research and the integration of innovative methodologies and technologies promises to revolutionize forensic taphonomy practices.
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Desecación , Desecación/métodos , Animales , Sudáfrica , Porcinos , Momias , Cambios Post Mortem , Estaciones del Año , Humanos , Ciencias Forenses/métodosRESUMEN
Population history-focused DNA and ancient DNA (aDNA) research in Africa has dramatically increased in the past decade, enabling increasingly fine-scale investigations into the continent's past. However, while international interest in human genomics research in Africa grows, major structural barriers limit the ability of African scholars to lead and engage in such research and impede local communities from partnering with researchers and benefitting from research outcomes. Because conversations about research on African people and their past are often held outside Africa and exclude African voices, an important step for African DNA and aDNA research is moving these conversations to the continent. In May 2023 we held the DNAirobi workshop in Nairobi, Kenya and here we synthesize what emerged most prominently in our discussions. We propose an ideal vision for population history-focused DNA and aDNA research in Africa in ten years' time and acknowledge that to realize this future, we need to chart a path connecting a series of "landmarks" that represent points of consensus in our discussions. These include effective communication across multiple audiences, reframed relationships and capacity building, and action toward structural changes that support science and beyond. We concluded there is no single path to creating an equitable and self-sustaining research ecosystem, but rather many possible routes linking these landmarks. Here we share our diverse perspectives as geneticists, anthropologists, archaeologists, museum curators, and educators to articulate challenges and opportunities for African DNA and aDNA research and share an initial map toward a more inclusive and equitable future.
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ADN Antiguo , Genética de Población , Humanos , ADN Antiguo/análisis , África , Genómica , Población Negra/genéticaRESUMEN
INTRODUCTION: Informed consent is critical for maintaining the ethical standards associated with the utilization of human donor bodies by tertiary education institutions. Body donation programs undertake the responsibility for procuring human donor bodies for didactic and research purposes. However, its processes require scrutiny regarding best practice guidelines and the South African National Health Act (SA-NHA) (2013). Moreover, acknowledging and addressing the current perceptions of human body donation are indispensable in bridging the gap between academia and society. This study aimed to compare informed consent documentation and procedures across South African tertiary education institutions and their affiliated human body donation programs (HBDP) in accordance with international guidelines. The findings were used to create a human body donation form template aligned to current international best practices for consideration by the South African HBDP. METHODOLOGY: A review of information and consent forms collected from South Africa's eight HBDP was conducted. The analyses consisted of a broad evaluation of information provided, ranging from the terms-of-use for human donor bodies to the commitments made by HBDP to body-donors. The results were considered in conjunction with the International Federation of Associations of Anatomists and other recent publications on informed consent in HBDP. RESULTS: Only two of the eight HBDP provided information and consent forms in more than one language. Most allowed donors to select how their bodies will be utilized - education, training and/or research. Some (6/8) made provisions for the next-of-kin to receive the cremains. Only one tertiary educational institution mentioned the occurrence of a memorial service in its documentation. An HBDF template was created aligned to current international best practices for presentation and possible adaption by SA HBDP. DISCUSSION & CONCLUSIONS: Human body donation forms (HBDF) requires thorough examination for the promotion and sustainability of HBDP. Effective communication by employing standardized non-technical terminology conveyed in language that is understandable and native to potential donors facilitates the deliverance of informed consent. Inconsistencies regarding the use and management of bodies catalyze the weakening perception of human body donation. Thus, this process of securing informed consent for body donation should be conducted in conjunction with public awareness campaigns and underpinned by the necessary policy and legislative reform.
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Cadáver , Consentimiento Informado , Obtención de Tejidos y Órganos , Humanos , Sudáfrica , Obtención de Tejidos y Órganos/legislación & jurisprudencia , Obtención de Tejidos y Órganos/ética , Cuerpo Humano , Anatomía/educación , Donantes de TejidosRESUMEN
This study combines clinical and anthropological analyses to investigate the complex cranial pathology of a South African individual from the 19th century. The cranium was examined macroscopically and radiographically. Conducting a standard differential diagnosis was challenging given the complexity and uncommon nature of the pathology and required drawing on relatively sparse paleopathological and clinical case reports. Multiple conditions were identified including biparietal thinning, basilar invagination, platybasia, and complicated chronic frontal sinusitis, where the intracranial extension of sinus infection may likely have contributed to the individual's death. The authors urge for awareness of these uncommon conditions, as their presence can easily be overlooked or confound skeletal assessments. This clinical study contributes to the authors' understanding of uncommon and poorly described paleopathological diseases and will help to better facilitate their diagnosis in future research. It represents one of the first studies describing such an unusual cooccurrence of uncommon pathologies in an archeological individual.
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Cráneo , Humanos , Sudáfrica , Historia del Siglo XIX , Cráneo/diagnóstico por imagen , Cráneo/patología , Masculino , Paleopatología , Tomografía Computarizada por Rayos X , Diagnóstico DiferencialRESUMEN
Forensic taphonomic studies are regionally specific and improve time since death estimates for medico-legal casework. Within forensic taphonomy and carrion ecology, vertebrate scavengers are under-researched with many studies conducted using multiple, unclothed carcasses. This is a forensically unrealistic experimental design choice with unknown impact. The effect of variation in carrion biomass on the decomposition ecosystem, particularly where vertebrate scavengers are concerned, requires clarification. To assess the effect of carrion biomass load on vertebrate scavenging and decomposition rate, seasonal baseline data for single, clothed ~60 kg porcine carcasses were compared to clothed multiple-carcass deployments, in a forensically relevant habitat of Cape Town, South Africa. Decomposition was tracked via weight loss and bloat progression and scavenging activity via motion-activated cameras. The single carcasses decayed more quickly, particularly during the cooler, wetter winter, strongly correlated with concentrated Cape gray mongoose (Galerella pulverulenta) scavenging activity. On average and across seasons, the single carcasses lost 68% of their mass by day 32 (567 accumulated degree days [ADD]), compared to 80 days (1477 ADD) for multi-carcass deployments. The single carcasses experienced substantially more scavenging activity, with longer visits by single and multiple mongooses, totaling 53 h on average compared to 20 h for the multi-carcass deployments. These differences in scavenging activity and decay rate demonstrate the impact of carrion biomass load on decomposition for forensic taphonomy research. These findings need corroboration. However, forensic realism requires consideration in taphonomic study design. Longitudinally examining many single carcasses may produce more forensically accurate, locally appropriate, and usable results.
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Ecosistema , Herpestidae , Animales , Porcinos , Sudáfrica , Tamaño de la Porción , Cambios Post Mortem , Conducta AlimentariaRESUMEN
INTRODUCTION: Through museum collecting practice, the deceased, possessions, plants and animals were turned into objects, removed from their communities and places of origin, and were segregated and divided into museum classificatory systems. In the decolonial work of embarking upon purposeful and proactive acts of return, the terms "repatriation" and "restitution" have often been used interchangeably. OBJECTIVE: To assess the terminological differences between repatriation and restitution. METHODS: Here, we critically discuss the politics of these terms and present an argument for restitution as restitutionary work. RESULTS: Repatriation refers to the legal, administrative and logistical matters of returning across national borders. However, restitution is a preferred concept highlighting deeper meanings of return to the proper owner, with restitutionary work being time-consuming, emotional, often painful, enriching acts of restoration, and transitional justice. Restitution is about the embodiment and empowerment of choice over all aspects of the return. CONCLUSION: Here, we argue that terminology matters. While restitution may involve repatriation, repatriation is not a substitute for acts of restoration embodied in restitutionary work.
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Propiedad , PolíticaRESUMEN
OBJECTIVE: To identify, critically analyse and describe severe bilateral skeletal pathology involving the ossa coxae of an individual from historic era Cape Town. MATERIALS: A single individual from the University of Cape Town's Human Skeletal Repository was analysed under research approval (HREC# 035/2021). METHODS: An osteobiography was constructed, radiocarbon dating and isotopic analyses were conducted. Pathological description and contextualised disability analyses followed, along with differential diagnosis. The pelvis and femora were visualised macroscopically and radiographically. RESULTS: This individual was a non-European middle-aged adult male who lived in the 17-18th centuries CE. Morphological changes showed hypoplastic hips with collapsed femoral heads and neoacetabulae. A diagnosis of developmental dysplasia of the hips (DDH) was made. Then a contextualised disability analysis including consideration of the clinical and functional impacts of the condition were applied. No signs of maltreatment, physiological stress or persistent infections were present. His bones were well developed, illustrating mobility and use. CONCLUSIONS: He developed DDH early in life and lived through adulthood, and his strong, healthy bones suggest resilience, some mobility and contribution to society through less physically demanding tasks. SIGNIFICANCE: Value for palaepathological analyses to inform and understand disability and culturally significant health mediation to offer a more objective interpretation and improve understanding of past people. It expands our understanding of the presence of DDH globally and in Africa and provides insight into disease impact for individuals with bilateral expression. SUGGESTIONS FOR FUTURE RESEARCH: Further contextual research is required. LIMITATIONS: Poor scene recovery hindered in-depth care analysis and interpretation of the condition.
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Luxación Congénita de la Cadera , Luxación de la Cadera , Adulto , Persona de Mediana Edad , Humanos , Masculino , Luxación de la Cadera/patología , Sudáfrica , Fémur/patología , Cabeza Femoral/patologíaRESUMEN
OBJECTIVES: Distal fractures of the humerus and their complications have rarely been described or analysed in the palaeopathological literature. The objective of this study was to evaluate two cases of distal humeral fracture with associated cubitus valgus observed in two individuals from the context of the Later Stone Age (LSA) in southern Africa. MATERIALS: Skeletal remains of two individuals. A middle-aged female radiocarbon dated to c.160 BP and a middle-aged male radiocarbon dated to c.2 300 BP. METHODS: Remains were macroscopically and radiographically assessed for injury. RESULTS: Both cases presented with healed antemortem injury to the right elbow attributed to possible falls. Distal humeral fracture resulted in non-union of the lateral epicondyle with extensive morphological changes to the elbow joint including an increased carrying angle. Morphological and osteoarthritic changes suggest a survival period of several years post-injury. SIGNIFICANCE: Cubitus valgus following traumatic injury has rarely been reported amongst historic or prehistoric populations. The described injuries would have had physical and functional consequences, raising questions relating to probable care received during the healing process. The elbow injuries would have resulted in restricted motion and instability of the elbow joint, with a high likelihood of ulnar neuropathy. LIMITATIONS: The contextual information for these individuals is limited and do not permit broader population level study. SUGGESTIONS FOR FURTHER RESEARCH: Formal biomechanical analysis including cross-sectional geometry analysis will provide further information regarding complications and strengthen the diagnosis of ulnar neuropathy. Further research is necessary on the prevalence and complications of humeral fracture.
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Fracturas Humerales Distales , Traumatismo Múltiple , Neuropatías Cubitales , Persona de Mediana Edad , Humanos , Masculino , Femenino , Resultado del Tratamiento , Fijación Interna de Fracturas , África AustralRESUMEN
We describe a process of restitution of nine unethically acquired human skeletons to their families, together with attempts at redress. Between 1925-1927 C.E., the skeletonised remains of nine San or Khoekhoe people, eight of them known-in-life, were removed from their graves on the farm Kruisrivier, near Sutherland in the Northern Cape Province of South Africa. They were donated to the Anatomy Department at the University of Cape Town. This was done without the knowledge or permission of their families. The donor was a medical student who removed the remains from the labourers' cemetery on his family farm. Nearly 100 years later, the remains are being returned to their community, accompanied by a range of community-driven interdisciplinary historical, archaeological and analytical (osteobiographic, craniofacial, ancient DNA, stable isotope) studies to document, as far as possible, their lives and deaths. The restitution process began by contacting families living in the same area with the same surnames as the deceased. The restitution and redress process prioritises the descendant families' memories, wishes and desire to understand the situation, and learn more about their ancestors. The descendant families have described the process as helping them to reconnect with their ancestors. A richer appreciation of their ancestors' lives, gained in part from scientific analyses, culminating with reburial, is hoped to aid the descendant families and wider community in [re-]connecting with their heritage and culture, and contribute to restorative justice, reconciliation and healing while confronting a traumatic historical moment. While these nine individuals were exhumed as specimens, they will be reburied as people.
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Antropología , Arqueología , Humanos , Sudáfrica , Cementerios , ADN AntiguoRESUMEN
OBJECTIVE: Palaeopathological evidence of cancer, especially metastatic cancer, is rare in China. This paper describes and diagnoses a cranium with multiple lytic lesions recovered from the Sampula cemetery in Xinjiang, attempting to diagnose the type of disease that could have caused the pathological lesions observed. MATERIAL: A cranium from an adult male (#00106) was recovered from the Sampula cemetery (dated to 55 BCE to 335 CE) located in the Luopu County, the Hotan River oasis on the southern edge of the Tarim Basin in southern Xinjiang. METHODS: The cranium was assessed macroscopically and radiographically (CT). RESULTS: Multiple osteolytic lesions with irregular and "moth-eaten" margins were detected in cranium #00106. CT scans revealed the development of the lesions began at the diploe and identified a "button sequestrum". CONCLUSIONS: Based on lesion characteristics, metastatic carcinoma was likely the cause of lesions found in cranium #00106. SIGNIFICANCE: This case has expanded our knowledge of the malignant neoplasms of ancient populations in northwest China and discusses the possible risk factors in the occurrence of cancer in the Sampula site, as well as the possible impacts of skeletal metastases on the individual. LIMITATIONS: The distribution of osteolytic lesions over the complete skeleton cannot be observed because of the unavailability of postcranial bone. SUGGESTIONS FOR FUTURE RESEARCH: With the increasing number of reports describing diseases in ancient China, the patterns of diseases occurrence and development can be further explored from spatial and temporal perspectives.
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Carcinoma , Carcinoma/secundario , Cementerios , China , Historia Antigua , Humanos , Masculino , Cráneo/patologíaRESUMEN
The oral microbiome plays key roles in human biology, health, and disease, but little is known about the global diversity, variation, or evolution of this microbial community. To better understand the evolution and changing ecology of the human oral microbiome, we analyzed 124 dental biofilm metagenomes from humans, including Neanderthals and Late Pleistocene to present-day modern humans, chimpanzees, and gorillas, as well as New World howler monkeys for comparison. We find that a core microbiome of primarily biofilm structural taxa has been maintained throughout African hominid evolution, and these microbial groups are also shared with howler monkeys, suggesting that they have been important oral members since before the catarrhine-platyrrhine split ca. 40 Mya. However, community structure and individual microbial phylogenies do not closely reflect host relationships, and the dental biofilms of Homo and chimpanzees are distinguished by major taxonomic and functional differences. Reconstructing oral metagenomes from up to 100 thousand years ago, we show that the microbial profiles of both Neanderthals and modern humans are highly similar, sharing functional adaptations in nutrient metabolism. These include an apparent Homo-specific acquisition of salivary amylase-binding capability by oral streptococci, suggesting microbial coadaptation with host diet. We additionally find evidence of shared genetic diversity in the oral bacteria of Neanderthal and Upper Paleolithic modern humans that is not observed in later modern human populations. Differences in the oral microbiomes of African hominids provide insights into human evolution, the ancestral state of the human microbiome, and a temporal framework for understanding microbial health and disease.
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Evolución Biológica , Ecología/métodos , Hominidae/microbiología , Metagenoma/genética , Microbiota/genética , Boca/microbiología , África , Animales , Bacterias/clasificación , Bacterias/genética , Biopelículas , Placa Dental/microbiología , Geografía , Gorilla gorilla/microbiología , Hominidae/clasificación , Humanos , Pan troglodytes/microbiología , FilogeniaRESUMEN
The University of Cape Town (UCT) Human Skeletal Repository began in 1913 and its composition a century later reflects the history of biological anthropology at the University, in South Africa and internationally. It consists of 1059 skeletons from archaeological (472; 44%), cadaveric (372; 36%) and forensic contexts (160; 14%). They are used for educational and research purposes to provide engaged scholarship and experiential learning for undergraduate and postgraduate students from a variety of disciplines including health professionals. The cadaveric remains help build population specific standards, forensic cases assist to address social and criminal justice, and the archaeological discoveries to preserve African culture and heritage. Overall, the repository provides a distinct contribution to knowledge locally and globally. The new management approach of the repository is presented. Ethical considerations and management policies are discussed. Stewardship of these individuals is facing several challenges and there are areas that continue to require attention. UCT is committed to address past unethical procurement of remains through engaging with the relevant interested and affected parties in restitution and repatriation.
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Universidades , Humanos , SudáfricaAsunto(s)
Arqueología/ética , ADN Antiguo , Investigación Genética/ética , Genómica/ética , África , Restos Mortales , Humanos , Consentimiento InformadoRESUMEN
Unidentified, decomposed and skeletonised human remains are frequently found in South Africa, therefore, standardised, reliable and relevant sex and ancestry estimation methods are required for forensic identification. This study assessed sex and ancestral variation in zygomatic size and shape in a South African population using geometric morphometric analyses. The zygoma of 158 South African individuals were sampled. Eight zygomatic landmarks were captured in 3-dimensions using a Microscribe G2 digitiser and assessed using procrustean geometric morphometrics. Shape and size differences were analysed using multivariate linear regression, discriminant function and canonical variate analyses. Males had significantly larger zygomas than females. Significant shape variation was found between ancestral groups. Bantu-speaking and Mixed ancestry individuals had narrower, shorter and more anteriorly projecting orbital margins, whilst Europeans had vertically elongated and receded orbital margins. European ancestral groups were most discernible from Bantu-speakers and Mixed ancestral groups. Ancestry estimation accuracies improved when ancestry was aggregated with sex. Pairwise ancestry-linked comparisons in females were as follows; Bantu-speakers (76%) from Europeans (72%), Bantu-speakers (71%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (63%). Similarly, ancestry-linked comparisons in males were as follows; Bantu-speakers (77%) from Europeans (81%), Bantu-speakers (53%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (82%). Size differences are putatively linked to variations in hormone-regulated growth and muscular robusticity between males and females. Shape variations between ancestral groups are likely attributable to the heterogenous genetic and ancestral origins of the South African population. It is challenging to distinguish between South Africa Bantu speakers and Mixed ancestry people due to Mixed ancestry individuals having variable genetic contributions from Khoesan, Bantu-speakers, Europeans and Asians. Bantu-speaking and Mixed ancestry people had zygomatic morphologies consistent with historical thermoregulatory adaptations to sub-Saharan climates, reported in African-descendants. Zygomatic morphology in European descendants suggests ancestral origins from colder climatic regions. This study demonstrated the utility of the zygoma in distinguishing between ancestral groups in South Africa, but further research is required to develop population-specific standards to distinguish between South African populations with shared African ancestry. The zygoma shows a promising ability to estimate sex and ancestry in South Africans, suggesting population specific standards for this bone may be of forensic interest.
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Población Negra , Población Blanca , Pueblo Asiatico , Análisis Discriminante , Femenino , Humanos , Masculino , SudáfricaRESUMEN
With research providing conflicting results from different habitats across the globe, the effect of clothing on decomposition is unclear; some studies indicate clothing increases decomposition rate by facilitating increased insect activity, and others conclude clothing prolongs the decay process. In South Africa, such research is lacking, with no data for the Western Cape Province, which suffers from a high murder rate with many unclaimed, unidentified bodies. Improving post-mortem interval (PMI) estimates will increase chances of correct forensic identification of decedents by narrowing the search window for police. Since no current PMI estimation method accounts for the possible influence of clothing, this study was designed to examine the effect of seasonally appropriate common clothing on decomposition rate in the thicketed Cape Flats Dune Strandveld, Cape Town, a forensically significant region. Four â¼60 kg domestic pig carcasses (Sus scrofa domesticus) were used as proxies for human decomposition, two were clothed and two unclothed. The clothing, altered by a seamstress to ensure an appropriate fit, caused a notable decrease in decay rate in this initial sample. Daily weight loss was used as a quantitative measure of decomposition progression, as the clothing prevented the use of visual decomposition scoring systems. Weight loss was closely associated with scavenging activity by the Cape grey mongoose (Galerella pulverulenta), with a clear scavenger preference for unclothed carcasses. This suggests that the effect of clothing on decomposition may be better assessed in this environment by examining how scavengers interact with only a single clothed carcass.
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Vestuario , Conducta Alimentaria , Herpestidae , Cambios Post Mortem , Animales , Patologia Forense , Humanos , Modelos Animales , Estaciones del Año , Sudáfrica , PorcinosRESUMEN
Forensic taphonomy as a discipline requires standardization to satisfy Daubert criteria for scientific data to be admissible in court. In response, there has been a shift towards quantification of methodology and estimating the postmortem interval. Despite these advances, there are still biases and limitations within the discipline not explicitly addressed in the early stages of experimental design nor in final published works. In this article, unresolved debates with respect to the conductance and reporting of forensic taphonomic research are reviewed, beginning with the nature of experimental cadavers, human or animal analogues and their body size, and second, the forensic realism of experimental setups, specifically with respect to caging, clothing and number of carcases. Pigs, albeit imperfect, are a good model to gain a general idea of the trends that may be seen in humans in subsequent validation studies in facilities where human donors are available. To date, there is no consensus among taphonomists on the extent of the effect that body mass has on decomposition progression. More research is required with both human cadavers and non-human analogues that builds on our current knowledge of forensic taphonomy to answer these nagging questions. This will enable the discipline to make the reliable assumption that pigs and donor decomposition data can be applied to homicide cases. A suite of experimental design aspects is suggested to ensure systematic and standardized data collection across different biogeoclimatic circumstances to identify and quantify the effects of potential confounding variables. Such studies in multiple, varied biogeographic circumstances with standardized protocols, equipment and carrion will facilitate independent global validation of patterns. These factors are reviewed to show the need for adjustments in experimental design to ensure relevance and applicability of data within locally realistic forensic situations. The initiation of a global decomposition data network for forensic taphonomists is recommended.Key pointsPigs are a valuable, albeit imperfect, proxy for human decomposition studies.There are few or conflicting data on effects of carcase size, carrion ecology, exclusion cages and scavengers.We recommend single, clothed, uncaged carcases for baseline research to reflect regionally specific forensic casework.
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In forensic death investigations, estimating the postmortem interval (PMI) is critical. An accurate PMI estimate increases the speed and accuracy of identifying the remains by narrowing the time frame in which the death occurred, thus reducing the pool of possible decedents. Cape Town, South Africa has a high level of unnatural death, and due to a burdened death investigation system, many remain unidentified. There has been a tendency to broadly apply quantitative models of decomposition across biogeographically unique circumstances. A prime example is the widespread application of the total body score (TBS)/accumulated degree day (ADD) model developed by Megyesi et al. (2005), later refined by Moffatt et al. (2016). However, the appropriateness of applying a single model to a wide range of locations with unique geography and climates remains in question. The aim of the study was to evaluate and compare the accuracy of Megyesi and Moffatt models for estimating PMI in Cape Town, South Africa. Using pig carcasses, Finaughty established baseline data on the rates and patterns of terrestrial decomposition in summer and winter in two different locations in a forensically significant area of Cape Town. Among the baseline data, Finaughty derived TBS values using the Megyesi criteria. The present study used these values to estimate the ADD per the Megyesi and Moffatt models, which would correspond to an estimated PMI. These estimated values were compared to actual ADD values. Estimates of ADD were inaccurate for both models in winter, and only partially in summer. The Moffatt model was more accurate in earlier decomposition stages, with the Megyesi model more accurate in later decomposition stages. These results indicate the Cape Town environments may contain factors that the two models do not consider, producing inaccurate PMI estimations at various TBS' values. ADD does not depict the entire taphonomic story; the decomposition process appears to be too complex for universal modelling based on a single or narrow suite of variables. Seasonality was an important factor in determining the accuracy of the models, primarily resulting in underestimations of the true PMI values. These findings show the impracticality of applying models developed for- or in one region to any other and support the need to establish regionally-specific equations for estimating PMI in a forensic context. Alternatively, more complex models employing "big data" from a more comprehensive suite of variables which influence the rate and pattern of decay could be developed.
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Modelos Estadísticos , Cambios Post Mortem , Temperatura , Animales , Ecosistema , Patologia Forense/métodos , Modelos Animales , Estaciones del Año , Sudáfrica , PorcinosRESUMEN
Dental root fractures are rarely documented in past human populations, but when they are observed, diagnosing ante-mortem events as causal factors can be difficult due to postmortem alteration. Can high resolution X-ray computed tomography (CT) improve our ability to diagnose if a dental fracture was caused ante- or post-mortem? To test this, a case study of two individuals with previously diagnosed dental root fractures were re-examined with high resolution CT to confirm or refute the original diagnoses. For individual 4170, use of high resolution CT supported the original diagnosis of an ante-mortem root fracture on the right mandibular central incisor that was made based on planar X-ray. With the new analyses, the root fracture was found to be associated with evidence of calcification, and with radicular and alveolar bone resorption, which are positive correlates of an ante-mortem origin. Resolving this level of detail of bone modification was not possible without using high resolution CT. For individual 4172, the use of high resolution CT enabled visualisation of fracturing and cracking throughout several molars and crowns of other teeth that were not evident in planar X-ray, suggesting that these fractures were likely produced by post-mortem taphonomic processes rather than ante-mortem events as originally diagnosed. In this case study, high resolution CT offered critical advantages compared to a planar X-ray approach, such as using 3D multiple slice views without superimposing alveolar bone and teeth as in planar X-ray imaging. This study demonstrates the potential of high resolution CT in confirming and refuting ante-mortem processes, and that visualisation of 3D structures is crucial for arriving at definitive diagnoses.