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Abstract

Dental microwear texture analysis (DMTA) is a common wear proxy using dental wear features to reconstruct diet in extant and extinct taxa. Dietary reconstructions of extinct species can be biased due to post-mortem mechanical modification of the dental surface. These post-mortem surface alterations can be caused by material loss after death, or as the result of burial, excavation, or preparation processes. In this study, we explore post-mortem surface alterations that occur during excavation, preparation, and conservation processes. We present a first general overview of unsuitable and suspicious dental surface scans and describe them both qualitatively and quantitatively using dental microwear texture (DMT) parameters. Finally, we compare these taphonomically altered surfaces to dental surfaces formed only by contact with a natural, ingested diet. We show that non-ingesta-related surfaces vary widely in morphologies. While some altered surfaces such as large post-mortem scratches or cracks in the enamel are easy to distinguish from ante-mortem ingesta-related wear features, others, such as remaining varnish covering the dental surface, are more obscure. The compiled surface defects dataset reveals that post-mortem altered surfaces often overlap with the parameter space of ingesta-related dental surfaces, but usually also include outliers with extreme values. To best identify dental surfaces with strong post-mortem alteration, we suggest using quantitative thresholds for frequently used DMT parameters for ingesta-related enamel surfaces based on literature values. However, with sufficient training and a reference database, these altered surfaces are detectable by an experienced user. Here we have compiled a first visual database of non-ingesta-related dental wear to help DMTA users identify these features and improve future DMTA studies.