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Abstract

Experimental approaches are often used to better understand the mechanisms behind
and consequences of post-mortem alteration on proxies for diet reconstruction.
Dental microwear texture analysis (DMTA) is such a dietary proxy, using dental wear
features in extant and extinct taxa to reconstruct feeding behaviour and mechanical
food properties. In fossil specimens especially, DMTA can be biased by post-mortem
alteration caused by mechanical or chemical alteration of the enamel surface. Here
we performed three different dental surface alteration experiments to assess the effect
of common taphonomic processes by simplifying them: (1) tumbling in sediment
suspension to simulate fluvial transport, (2) sandblasting to simulate mechanical
erosion due to aeolian sediment transport, (3) acid etching to simulate chemical
dissolution by stomach acid. For tumbling (1) we found alteration to be mainly
dependent on sediment grain size fraction and that on specimens tumbled with sand
fractions mainly post-mortem scratches formed on the dental surface, while specimens
tumbled with a fine-gravel fraction showed post-mortem formed dales. Sandblasting
(2) with loess caused only negligible alteration, however blasting with fine sand quartz
particles resulted in significant destruction of enamel surfaces and formation of large
post-mortem dales. Acid etching (3) using diluted hydrochloric acid solutions in
concentrations similar to that of predator stomachs led to a complete etching of the
whole dental surface, which did not resemble those of teeth recovered from owl pellets.
The experiments resulted in post-mortem alteration comparable, but not identical to
naturally occurring post-mortem alteration features. Nevertheless, this study serves
as a first assessment and step towards further, more refined taphonomic experiments
evaluating post-mortem alteration of dental microwear texture (DMT).