An Investigation Into the Relationship Between Funerary Treatment and Bacterial Bioerosion in European Archaeological Human Bone

Abstract

A central problem in funerary archaeology is interpreting how the corpse was manipulated in the immediate post mortem period. The extent of bacterial bioerosion to the internal bone microstructure has been proposed as a means to infer the early post mortem history of a corpse, as it has been suggested that this form of bone diagenesis is produced by an organism's putrefactive gut bacteria. Under this model, different forms of funerary treatment would be expected to leave characteristic signatures of bioerosion in archaeological bone. Here, we tested the extent to which bacterial bioerosion of ancient human bones reflected funerary treatment, through histological analysis of 301 archaeological human bone thin sections from 25 European archaeological sites. We found that bioerosion was significantly influenced by whether a bone originated from a neonatal individual or an anoxic context. When these remains were excluded, bioerosion was controlled by archaeological phase in a manner consistent with known early post mortem treatment and forensic models of bodily decomposition. These findings suggest that microscopic analyses of bone have useful applications in reconstructions of funerary processes and provide some insight into factors that may control the persistence of organic biomolecules and fossilization.

Holding on to the past: Southern British evidence for mummification and retention of the dead in the Chalcolithic and Bronze Age

“…Histological degradation was consistent with Hackett's (1981, 250) non-Wedl MFD (bacterial bioerosion) in all cases (Jans et al 2004). Variation in bacterial bioerosion has been linked to early taphonomic processes which affect the level of putrefactive decomposition undergone by a skeleton (Jans et al 2004;Nielsen-Marsh et al 2007;White & Booth 2014;Booth 2015). Bones retrieved as part of articulated complete skeletons are usually extensively bioeroded, as the immediate burial of an intact corpse protects it from rapid defleshing by scavengers, thereby exposing the skeleton to extensive bacterial soft tissue decomposition.…”

“…It is likely that the brown staining within the F1 sample was caused by decomposition products from the surrounding coffin. Although F1 was coffined, permeable wooden coffins rarely impede bodily decomposition or bioerosion in well-drained environments (Booth 2015). The articulation of the F1 skeleton precludes the possibility that it was rapidly defleshed.…”

“…Small parts of the F1 bone thin section had been stained dark brown. This kind of staining is thought to be caused by environmental humic substances and is most often found in bone from contexts which included high levels of decomposing organic material (Booth 2015). It is likely that the brown staining within the F1 sample was caused by decomposition products from the surrounding coffin.…”

“…The microstructure of the F1 sample was anomalously well-preserved and comparable to fresh bone. This specimen appears to have suffered little, if any, putrefactive decomposition, which is unusual for a bone from a complete articulated adult skeleton (Booth, 2015). Anoxic or waterlogged environments can inhibit decomposition and reduce bioerosion (Turner-Walker & Jans 2008;Hollund et al 2012; Booth et al, in press), but these conditions are unlikely to have been prevalent in the local free-draining sediments.…”

“…Mummified bodies are the only ancient articulated human remains whose bones consistently demonstrate low levels of bacterial bioerosion . Therefore, the best explanation for the anomalous diagenetic signature of the F1 individual is that it was mummified before being buried, in common with skeletons recovered from several British Bronze Age sites (Parker Pearson et al 2005;Booth et al 2015). …”