MicroWeaR: A new R package for dental microwear analysis

Abstract

Mastication of dietary items with different mechanical properties leaves distinctive microscopic marks on the surface of tooth enamel. The inspection of such marks (dental microwear analysis) is informative about the dietary habitus in fossil as well as in modern species. Dental microwear analysis relies on the morphology, abundance, direction, and distribution of these microscopic marks. We present a new freely available software implementation, MicroWeaR, that, compared to traditional dental microwear tools, allows more rapid, observer error free, and inexpensive quantification and classification of all the microscopic marks (also including for the first time different subtypes of scars). Classification parameters and graphical rendering of the output are fully settable by the user. MicroWeaR includes functions to (a) sample the marks, (b) classify features into categories as pits or scratches and then into their respective subcategories (large pits, coarse scratches, etc.), (c) generate an output table with summary information, and (d) obtain a visual surface‐map where marks are highlighted. We provide a tutorial to reproduce the steps required to perform microwear analysis and to test tool functionalities. Then, we present two case studies to illustrate how MicroWeaR works. The first regards a Miocene great ape obtained from through environmental scanning electron microscope, and other a Pleistocene cervid acquired by a stereomicroscope.

Sauropod dinosaur teeth from the lower Upper Cretaceous Winton Formation of Queensland, Australia and the global record of early titanosauriforms

“…Microwear features were classified as either large or small pits, and fine or coarse scratches. Classification of each feature is as follows: if the length/width ratio is less than or equal to 4 µm it is considered a pit, if greater than 4 µm it is considered a scratch [53]. If a pit has a diameter of less than or equal to 8 µm it is considered a small pit, while if a scratch has a width of less than or equal to 3 µm it is considered fine [53].…”

“…Classification of each feature is as follows: if the length/width ratio is less than or equal to 4 µm it is considered a pit, if greater than 4 µm it is considered a scratch [53]. If a pit has a diameter of less than or equal to 8 µm it is considered a small pit, while if a scratch has a width of less than or equal to 3 µm it is considered fine [53]. Percentage of scratches that were ‘parallel’ or ‘crisscross’ ( sensu [53]) were also identified.…”

Multipronged dental analyses reveal dietary differences in last foragers and first farmers at Grotta Continenza, central Italy (15,500–7000 BP)

“…Data collection of the buccal microwear features was performed using a Delphi implementation (version XE7, Embarcadero Technologies) of the MicroWeaR package 42 . MicroWeaR Delphi allows for the image pre-processing with image enhancement routines, high-pass, and directional kernel-based filtering, calibration of the image, ROI definition, and tracing of the scratches (Supplementary Fig.…”

Lifestyle changes and its effect towards the evolution of human dentition

“…The microscopic wear pattern left on the occlusal surfaces of teeth during the masticatory process is the primary focus of dental microwear analysis. Its evaluation is based on the morphology, abundance, direction, and distribution of the microscopic marks on the enamel surfaces (Scott and Halcrow 2017;Strani et al 2018).…”