Human Taphonomy Research Articles

Extraction and untargeted analysis of metabolome from undemineralised cortical bone matrix.

Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) untargeted metabolomics has become the gold standard for the profiling of low-molecular-weight compounds. Recently, this discipline has raised great interest in forensic sciences, especially in the field of toxicology and for post-mortem interval estimation. The current study aims at evaluating three extraction protocols and two LC-MS/MS assays run in both positive and negative modes, to identify the most suitable method to conduct post-mortem metabolomic profiling of bone tissue. A fragment of the anterior tibia of a 82 years-old male sampled from a human taphonomy facility was powdered via freeze-milling. The powdered sub-samples were extracted in five replicates per protocol. Methods tested were (I) a biphasic chloroform-methanol-water protocol, (II) a single phase methanol-water protocol, and (III) a single phase methanol-acetonitrile-water protocol. LC-MS/MS analyses were carried out via high performance liquid chromatography, either on hydrophilic interaction (HILIC) or on reversed-phase (C18) columns in both positive and negative ionisation modes, coupled with a Q-TOF mass spectrometer. Results suggest that the highest consistency between replicates and quality control samples was obtained with the single phase extractions (i.e., methanol-acetonitrile-water), whilst the ideal combination of instrumental set up HILIC chromatography in positive ionisation mode and of C18 chromatography in negative ionisation mode. For the purpose of forensic investigations, a combination of a single phase extraction and the two aforementioned chromatographic and mass spectrometry modes could represent an ideal set up for obtaining bone metabolomic profiles from taphonomically altered bones.

A soil-based approach on human taphonomy from five Portuguese public cemeteries

ABSTRACT Over the last decade, some Portuguese cemeteries have started to have issues with the lack of burial space, mainly due to the slow rate of cadaveric decomposition, hindering the reuse of soil graves as is common practice. To better understand the influence of soil on human taphonomy and help in cemetery management, the main goal of this research was to explore possible relationships between body decay and edaphic traits. A total of 217 soil samples were collected from graves of five public cemeteries and analysed for their soil organic matter content, moisture, pH, electrical conductivity, bulk density, texture, and colour. Five grave sampling areas were considered: the topsoil, above the coffin, and under the coffin in the head, pelvis and feet areas. Statistically significant differences have been found between the graves of skeletonized and incompletely skeletonized bodies for moisture above the coffin (p = 0.035) and for electrical conductivity in the topsoil (p = 0.014). Although the number of individuals (n = 56) studied might be considered low, this paper explores the possibility that soil itself might not be the main influencer on human taphonomy. A new perspective should be considered regarding the role played by intrinsic factors after death.

The impact of freezing on the post-mortem human microbiome

IntroductionHuman donations are often used in forensic research as they can provide unique insights into post-mortem research that cannot be obtained with animal proxies. This is especially true for forensic microbiome research, as human circumstances such as drug-use or health conditions may influence the post-mortem microbiome. However, it is not always feasible to conduct such research immediately after death. Donors are often stored frozen in human taphonomy facilities, pending the start of any experimental study, yet little is known about how freezing may affect their microbiome.MethodsWe assessed the effects of freezing on the post-mortem human microbiome by analysing the microbial diversity and abundance of seven human donors at the Forensic Anthropology Center at Texas State (FACTS) before and after freezing. Swab samples were taken from five locations on each corpse upon arrival to FACTS and again after they had been frozen in storage for a period ranging between 11 and 40 days and subsequently thawed.ResultsAfter performing the microbiome analysis of the swabs via 16S rRNA gene metabarcoding, we found changes in the abundance levels of Proteobacteria, Bacteroidota and Firmicutes, as well as the presence of the new phyla Deinococcota and Myxococcota after freezing. However, none of these changes were significant when comparing community diversity before and after freezing.DiscussionOverall, our results show that the observed changes in the abundance of specific phyla before and after freezing are negligible, that freezing does not significantly alter the human microbiome and that frozen donors are suitable for forensic studies on the human thanatomicrobiome.

Developing a new scoring method to evaluate human decomposition in a humid, continental (Dfb) climate in Quebec.

The published literature shows a lack of methods to evaluate the patterns and extent of decomposition of human remains and to estimate the post-mortem interval (PMI) in humid, continental (Dfb) climates such as Quebec. The aim of this study was to address this gap in the current knowledge base by providing the first observations from human corpses studied under controlled conditions in Quebec. A 12-month study was conducted at the site for Research in Experimental and Social Thanatology; the first human taphonomy facility in Canada. Six human donors with known time of death were deposited across spring (n= 1), summer (n= 3), and autumn (n= 2) 2021. The lack of suitability of the total body score method to evaluate the extent of decomposition at the facility prompted the development of a new scoring system based on the macromorphoscopic changes observed. The scoring system was applied to the donors to evaluate decomposition throughout seasons. All donors followed comparable decomposition trajectories, regardless of the season of deposition. Eighty-five percent of taphonomic patterns appeared in the first 25 experimental days or 5000 Kelvin accumulated degree days (350 ADD). Extensive desiccation of tissues was observed at a median of 21 experimental days across donors, resulting in a plateau within decomposition with no extensive skeletonization. To the authors' knowledge, this is the first published report of experimentally observed desiccation in such a form in a Dfb climate. This study provides new data on the types of decomposition patterns to expect in forensic investigations in southern Quebec and comparable climates.

The impact of maceration on the ‘Osteo-ome’; a pilot investigation

The bone proteome, i.e., the ‘osteo-ome’, is a rich source of information for forensic studies. There have been advances in the study of biomolecule biomarkers for age-at-death (AAD) and post-mortem interval (PMI) estimations, by looking at changes in protein abundance and post-translational modifications (PTMs) at the peptide level. However, the extent to which other post-mortem factors alter the proteome, including ‘maceration’ procedures adopted in human taphonomy facilities (HTFs) to clean bones for osteological collections, is poorly understood. This pilot study aimed to characterise the impact of these ‘cleaning’ methods for de-fleshing skeletons on bone biomolecules, and therefore, what further impact this may have on putative biomarkers in future investigations. Three specific maceration procedures, varying in submersion time (one week or two days) and water temperature (55 °C or 87 °C) were conducted on six bovid tibiae from three individual bovines; the proteome of fresh and macerated bones of each individual was compared. The maceration at 87 °C for two days had the greatest proteomic impact, decreasing protein relative abundances and inducing specific PTMs. Overall, these results suggest that routinely-employed maceration procedures are harsh, variable and potentially threaten the viability of discovering new forensic biomarkers in macerated skeletal remains. SignificanceFor the first time, the application of bone proteomics in understanding maceration procedures was conducted to help address the risks for experimental confounding associated with this post-mortem cleaning technique. This pilot study demonstrates that recent advances in biomarker discovery for post-mortem interval and age-at-death estimation using bone proteomics has potential for confounding by differing and destructive bone-cleaning methods.

The Importance of Soil on Human Taphonomy and Management of Portuguese Public Cemeteries

Cemeteries from the European Romantic period (18th–19th centuries) are often compared to small cities that hold memories, art, and history. Portuguese public cemeteries were first established in 1835 and became an interesting combination of fauna, flora, and monumental sculptures to mourn the dead at a location outside the limits of the city. Over the past 187 years, laws have been created and amended taking into consideration the needs of the population and the scientific knowledge available at each time point in history. Nevertheless, cemeteries have long been struggling with the lack of burial space which has been emphasised during the two years of the COVID pandemic. This work aims to review the development of Portuguese public cemeteries since their establishment, highlighting the imposed measures for the inhumation and exhumation of the deceased. It will also discuss the importance of soil as an abiotic agent, focusing on eight specific soil properties and their significance on the characterisation of graves. It is expected that a better understanding of the impact of soil on human taphonomy supports the role of city halls in managing public cemeteries, particularly the lack of burial space.

Documented Skeletal Collections and Their Importance in Forensic Anthropology in the United States

Documented skeletal collections are the backbone of forensic anthropology due to their associated biohistories. This paper describes the identified skeletal collections and their relevance in forensic anthropological research, education and training in the US. The establishment of documented skeletal collections in the US can be distinguished into two modus operandi, depending on the stance towards the dead, legislation, and medical and forensic practices. In the 19th and early 20th centuries, anatomists amassed skeletons from cadaver dissections, shaped by European influences. Those skeletons compose the anatomical collections—such as the Robert J. Terry Anatomical Collection—predominantly representing impoverished and unclaimed individuals. Ethical concerns for the curation and research of African American skeletons without family consent are growing in the US. In contrast, since the 1980s, modern documented skeletal collections originated from body donations to human taphonomy facilities, such as the William M. Bass Donated Skeletal Collection. The establishment and testing of osteological methods essential to establish one’s identity—such as age at death and sex—have been developed with skeletons from documented collections. Therefore, the analysis of identified skeletons has been crucial for the development of forensic anthropology in the US.

“Human Taphonomy Facility” Aka “The Body Farm”

“Human Taphonomy Facility” Aka “The Body Farm”

The Chemistry Decomposition in Human Corpses

Human body is a complex of organic substances (proteins, lipids, carbohydrates), which undergo chemical decomposition processes soon after death. The compounds released during decomposition characterize the development of different stages of this process: e.g. biogenic amines resulted from the proteins decomposition will confer the particular smell of a cadaver, gases resulted from carbohydrates fermentation will give the bloating aspect of the cadaver. The study of cadaver decomposition and the products resulted from this process is the subject of human taphonomy and is realized nowadays in special facilities in USA and Australia. Identification and analysis of the chemical compounds emerged after human decomposition (gases, liquids, salts) give valuable information to forensic pathologists for estimating the postmortem interval (PMI). More, volatile compounds � which give the odor signature�specific to human remains � may be utilized in identifying clandestine burials, human remains or victims entrapped under ruins in cases of natural disasters. In this paper the authors describe the chemical decomposition stages of human cadavers, the factors influencing these processes and utility for the forensic activity of the results of human taphonomic studies.

Taphonomic analysis of Bronze Age burials in Mongolian khirigsuurs

The role of the distinctive Mongolian Bronze Age mounds (khirigsuurs) has been debated for many years with authors divided over their funerary role. Interpretation of the presence or absence of human bone has been central to this debate. In this paper, we undertake a systematic analysis of human taphonomy at the Khövsgöl site to explain why mounds appear “empty”. In doing so we demonstrate a strong statistical relationship between the preservation of human bone and intrinsic circumstances related to the mound locations and the age of the deceased. In contrast, patterns of disarticulation are strongly correlated with human disturbance of graves post-mortem. We argue that statistical analysis of burials, recognising the continuity of potential preservation from nil to complete serves to explain the relative importance of taphonomic agents but allows for predictive analysis of where remains are most likely to be preserved. Such approaches are important in shifting studies of human taphonomy from a descriptive to analytical endeavour.

Chapter 10: Ancient Mortuary Ritual and Human Taphonomy

Abstract Human and nonhuman faunal remains from small deposits at three sites, NGRP 16, 23, and 46, were analyzed to determine the species and minimum numbers of individuals represented, and to investigate the processes of natural and human-induced modification that resulted in the extensive fragmentation of the human remains. Taphonomic analysis indicates perimortem modification of the human remains during disarticulation and processing as well as pig predation. The types and locations of tool marks, fractures, and fracture products are quantified and described, and quantitative taphonomic profiles for the human remains are compared to human and nonhuman bone assemblages from middens and normative burial contexts on Fiji. The NGRP assemblages do not taphonomically match other assemblages believed to represent incidents of cannibalism, but this does not rule out the consumption of human flesh or decomposition fluids. We reject the notion of a universal taphonomic signature of cannibalism, and find it more...

A Taphonomic Approach to Late Classic Maya Mortuary Practices at Xuenkal, Yucatán, Mexico

Following a brief introduction to mortuary practices in Prehispanic Maya society, we outline the analytical procedures followed during the excavation and laboratory investigation of five burial assemblages from the Late Classic period site of Xuenkal, Yucatán, Mexico. A detailed account of a sequence of primary and secondary interments is provided with a focus on taphonomic and biovital information, emphasizing the importance of an interdisciplinary approach, especially human taphonomy, for the reconstruction of complex Maya mortuary treatments. Our results show that bodies of the dead or their parts followed surprisingly long and complex funerary paths.

Human taphonomy at Khuzhir-Nuge XIV, Siberia: a new method for documenting skeletal condition

This paper employs a new three-part method for documenting skeletal condition in order to examine human taphonomy at the Glaskovo (5000–3700 BP, calibrated) cemetery of Khuzhir-Nuge XIV, located in the Lake Baikal region of Siberia (Russia). Relationships among three distinct aspects of condition – completeness, fragmentation, and articulation – and 15 identified taphonomic factors are investigated in order to explain the high variability observed at the site. Intrinsic skeletal characteristics such as element type and age at death were found to be responsible for some of the variable condition, but cultural activities, particularly mortuary practices, appear to have played even greater roles – both direct and indirect. Articulation, in particular, appears to have been an aspect of skeletal condition which was directly affected by a number of cultural practices. In addition to applying a new method of documenting skeletal condition to human taphonomic analyses, this research explains much of the variable condition observed at Khuzhir-Nuge XIV and emphasizes the significance of cultural practices as taphonomic agents affecting human remains.