Hege Ingjerd Hollund

Buried archaeological bones tend to be heavily degraded by microorganisms. This type of biodegradation was already identified in the 19 ^th century and remains a subject of continuous investigation. However, the underlying processes are still not fully understood, and the organisms responsible for the decay have not been clearly identified. Technological advances in genetic sequencing now allow detailed study of the bone microbiome. And yet, identifying the species causing the observed bioerosion has proven challenging. Relatively few studies have combined the investigation of bone degradation by microscopy, so-called histotaphonomy, with metagenomic analyses. This study aims to bridge this gap. We utilize a large set of human bone samples from medieval cemeteries in south-western Norway. Detailed microscopic analyses have been carried out, showing diverse levels of preservation. The extent of bioerosion is correlated with the results from metagenomic analyses as well as environmental factors. Microbiome diversity is greater and more evenly distributed in well-preserved bones with limited bioerosion, particularly those recovered from burials beneath church floors, contrasting with outdoor cemeteries. Fungal taxa were detected in only a single sample in the metagenomic data despite histological evidence of fungal structures, and their role in bone bioerosion remains unclear. Our findings show that preservation state is strongly associated with microbiome composition. The most prevalent genus found was Streptomyces, supporting previous research suggesting that bacteria within this group could be involved in bone bioerosion.

Buried archaeological bones tend to be heavily degraded by microorganisms. This type of biodegradation was already identified in the 19th century and remains a subject of continuous investigation. Yet the specific processes are still not fully understood, and the specific organisms responsible for the decay have not been identified. Technological advances in genetic sequencing now allow detailed study of the bone microbiome. And yet, identifying the species causing the observed bioerosion has proven challenging. Few studies have combined the investigation of bone degradation by microscopy, so-called histotaphonomy, with metagenomic analyses. This study aims to bridge this gap. We utilize a large a set of human bone samples from medieval cemeteries in south-western Norway. Detailed microscopic analyses have been carried out, showing diverse levels of preservation. The extent of bioerosion is correlated with the results from metagenomic analyses as well as environmental factors. Microbiome diversity is greater and more evenly distributed in well-preserved bones with limited bioerosion, particularly those recovered from burials beneath church floors, contrasting with outdoor cemeteries. Our findings show that preservation state is strongly associated with microbiome composition. The most prevalent genus found was Streptomyces, supporting previous research suggesting that bacteria within this group could be involved in bone bioerosion.

Degradation of archaeological bone is a complex process that is influenced by both intrinsic and extrinsic parameters. Here we study the decay of bones recovered from a large midden at the Inuit summer hunting camp, Aasivissuit, in West Greenland, dating from 1200 CE to 1950 CE. The site was partly excavated in 1978 and revisited for further excavation in 2021 to study changes in the materials’ state of preservation, both in situ and in museum storage. The state of preservation was described visually for several hundred bones from both investigations. The reactivity of 34 caribou bones was measured at −5˚C, 1˚C, 5˚C, 10˚C, and 15˚C, and compared to their density, composition, and histological decay pattern. Environmental monitoring on site included soil type, pH, porosity, water content, and temperature, while monitoring in storage included relative humidity and temperature. The observed degradation patterns and changes that occurred in the period 1978 – 2021 in situ and in museum storage are explained. Furthermore, current climate change predictions are used to evaluate what may happen to the site in the future. Findings include: 1) the bones preserved in situ showed little change since 1978, while the excavated bones in museum storage were more degraded; 2) the decay pattern for the bones is well correlated with environmental conditions; 3) the reactivity of wet bone measured as oxygen consumption was largely controlled by bone density and temperature; 4) loss of organic and mineral components of the bone under current conditions can be estimated using numerical models; and 5) continued in situ preservation under current and future climate conditions is considered feasible.

This study investigates possible variation in post-mortem histories during the Neolithic period in southwestern Sweden based on microscopic studies of human bone. Numerous megalithic graves were built in this region and good preservation conditions have left a rich skeletal record. After more than a hundred years of research, it is still a controversy whether or not these skeletal assemblages were the result of primary burials, or ossuaries where skeletonized remains were deposited. In this study we apply histological analysis to obtain insights into post-mortem histories and taphonomic processes affecting the human remains, potentially including funerary rituals. This type of analysis records the condition and traces of degradation found in skeletal material at a microscopic level. Human skeletal material from four different megalithic tombs in the Falbygden area has been sampled and analysed by thin-section light microscopy, and by scanning electron microscopy. The results of the study provide evidence of variation and changes in burial conditions for skeletal remains from the different graves, also for remains from the same grave. Extent of bioerosion varied, from extensive to moderate/arrested, to none. Bone samples from the same graves also differed in the type of staining and mineral inclusions, showing that the non-bioeroded samples relatively early post-mortem must have experienced an anoxic environment, and later a change to an aerated environment. This could be taken as an indication of primary burial somewhere else, but more likely reflect a special micro-environment occurring temporarily in some graves and parts of graves after the tombs were filled with soil and sealed by roof slabs. The study illustrates the usefulness of bone histological analysis in the reconstruction of post-mortem histories, revealing variations not discernible at macro-level that may aid in the interpretations of funerary rituals. However, the results also highlight the issues of equifinality. Based on current data and knowledge, several scenarios are possible. Further histotaphonomic work is advisable, including archaeological remains from megalithic tombs, and bones from taphonomic experiments.

Many archaeological bones display a heterogeneous degradation pattern. Highly degraded bones could contain pockets of well‐preserved bone, harbouring good quality DNA. This dichotomy may explain why the relationships between global bone preservation parameters such as histological integrity, bone mineral crystallinity or collagen yield, and bulk DNA preservation/amplification success rate have been found to be at best, weak to moderate. In this pilot study, we explore whether or not a more localised approach will highlight a stronger relationship between diagenetic parameters and DNA preservation. This study includes a detailed histological characterisation of bone diagenesis in sub‐areas of three bone samples. Regions of the same bone, which displayed differential degrees of preservation or type of diagenesis were sampled for further analysis and both genetic (small scale Illumina MiSeq sequencing) and chemical (Fourier‐transform infrared spectrometric analysis) analyses were performed. The aim was to investigate how bone diagenetic processes relate to DNA preservation at a higher resolution than in previous studies. This is key in order to improve DNA analytical success rates. The expected relationship between bone and DNA preservation (retrieved endogenous DNA) was observed and the results corroborate previous work that DNA preservation is linked to the integrity of bone collagen and mineral. The results further suggest that non‐biological diagenetic alterations such as etching and the presence of mineral infiltrations and inclusions have a negative effect on DNA preservation/extraction. Copyright © 2016 John Wiley & Sons, Ltd.

The dodo Raphus cucullatus Linnaeus, 1758 Linnaeus, C. 1758. Systema Naturae per Tegna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis. Tenth Edition. Laurentii Salvii, Stockholm , 824 pp. [Google Scholar] , an extinct and flightless, giant pigeon endemic to Mauritius, has fascinated people since its discovery, yet has remained surprisingly poorly known. Until the mid-19th century, almost all that was known about the dodo was based on illustrations and written accounts by 17th century mariners, often of questionable accuracy. Furthermore, only a few fragmentary remains of dodos collected prior to the bird's extinction exist. Our understanding of the dodo's anatomy was substantially enhanced by the discovery in 1865 of subfossil bones in a marsh called the Mare aux Songes, situated in southeastern Mauritius. However, no contextual information was recorded during early excavation efforts, and the majority of excavated material comprised larger dodo bones, almost all of which were unassociated. Here we present a modern interdisciplinary analysis of the Mare aux Songes, a 4200-year-old multitaxic vertebrate concentration Lagerstätte. Our analysis of the deposits at this site provides the first detailed overview of the ecosystem inhabited by the dodo. The interplay of climatic and geological conditions led to the exceptional preservation of the animal and associated plant remains at the Mare aux Songes and provides a window into the past ecosystem of Mauritius. This interdisciplinary research approach provides an ecological framework for the dodo, complementing insights on its anatomy derived from the only associated dodo skeletons known, both of which were collected by Etienne Thirioux and are the primary subject of this memoir. Citation for this article: Rijsdijk, K. F., J. P. Hume, P. G. B. de Louw, H. J. M. Meijer, A. Janoo, E. J. de Boer, L. Steel, J. de Vos, L. G. van der Sluis, H. Hooghiemstra, F. B. V. Florens, C. Baider, T. J. J. Vernimmen, P. Baas, A. H. van Heteren, V. Rupear, G. Beebeejaun, A. Grihault, J. van der Plicht, M. Besselink, J. K. Lubeek, M. Jansen, S. J. Kluiving, H. Hollund, B. Shapiro, M. Collins, M. Buckley, R. M. Jayasena, N. Porch, R. Floore, F. Bunnik, A. Biedlingmaier, J. Leavitt, G. Monfette, A. Kimelblatt, A. Randall, P. Floore, and L. P. A. M. Claessens. 2015. A review of the dodo and its ecosystem: insights from a vertebrate concentration Lagerstätte in Mauritius; pp. 3–20 in L. P. A. M. Claessens, H. J. M. Meijer, J. P. Hume, and K. F. Rijsdijk (eds.), Anatomy of the Dodo (Raphus cucullatus L., 1758): An Osteological Study of the Thirioux Specimens. Society of Vertebrate Paleontology Memoir 15. Journal of Vertebrate Paleontology 35(6, Supplement).

Teeth are often the preferred substrate for isotopic and genetic assays in archaeological research. Teeth can yield isotopic signals from different periods of an individual's lifetime, useful in dietary reconstruction, climate research, and investigation into mobility of people and animals in the past. Additionally, it is generally accepted that teeth preserve biomolecules (e.g. DNA, collagen) and isotopic signals better. Despite the importance of dental tissue in archaeological research, no systematic study has been carried out concerning diagenetic alterations at histological scale. This article reports the results of a thorough histological characterisation of post-mortem alterations observed in 34 ancient teeth. Such alterations are well described in bone whereas similar analyses of teeth are scant and highlight the need for diagenetic screening before analysis. Micrographs have been made, illustrating typical diagenetic features occurring within the dental tissues cementum, dentine and enamel including bioerosion, cracking, etching and staining. The photo catalogue produced can be used within fields such as archaeology, forensics and palaeontology