Investigating the Timing and Extent of Juvenile and Fetal Bone Diagenesis in a Temperate Environment

Abstract

It is well understood that intrinsic factors of bone contribute to bone diagenesis, including bone porosity, crystallinity, and the ratio of organic to mineral components. However, histological analyses have largely been limited to adult bones, although with some exceptions. Considering that many of these properties are different between juvenile and adult bone, the purpose of this study is to investigate if these differences may result in increased degradation observed histologically in fetal and juvenile bone. Thirty-two fetal (n = 16) and juvenile (n = 16) Sus scrofa domesticus femora subject to different depositions over a period of two years were sectioned for histological observation. Degradation was scored using an adapted tunneling index. Results showed degradation related to microbial activity in both fetal and juvenile remains across depositions as early as three months. Buried juvenile remains consistently showed the greatest degradation over time, while the blanket fetal remains showed more minimal degradation. This is likely related to the buried remains' greater contact with surrounding soil and groundwater during deposition. Further, most of the degradation was seen in the subendosteal region, followed by the subperiosteal region, which may suggest the initial microbial attack is from endogenous sources.

Keywords: bone diagenesis; histotaphonomy; juvenile skeletal remains.

Figure 1

A scatter plot illustrating the distribution of TI scores over time (time represented by ADD) by deposition. Best-fit simple regression lines are here to demonstrate the relationship between bacterial bioerosion and time.

Figure 2

Examples of tunneling index (TI) scores 1 to 3 for both fetal and juvenile sections from this study. (a) Fetal sample with a TI score of 1; (b) Fetal sample with a TI score of 2; (c) Fetal sample with a TI score of 3; (d) Juvenile sample with a TI score of 1; (e) Juvenile sample with a TI score of 2; (f) Juvenile sample with a TI score of 3. No samples were scored as 0 with no damage.

Figure 3

The histological sections from each deposition that were exposed for the approximate ADD from the destructive degradation probability model. All were deposited during the first spring season, with the bagged fetal, blanket fetal, and surface juvenile remains represented here having an ADD of 7246.89. The buried juvenile remains represented here have an ADD of 7494.78. (a) Bagged fetal cross-section (TI = 3); (b) Blanket fetal cross-section (TI = 3); (c) Buried juvenile cross-section (TI = 3); (d) Surface juvenile cross-section (TI = 2).