Complementary approaches to tooth wear analysis in Tritylodontidae (Synapsida, Mammaliamorpha) reveal a generalist diet

Abstract

Stereoscopic microwear and 3D surface texture analyses on the cheek teeth of ten Upper Triassic to Lower Cretaceous tritylodontid (Mammaliamorpha) taxa of small/medium to large body size suggest that all were generalist feeders and none was a dietary specialist adapted to herbivory. There was no correspondence between body size and food choice. Stereomicroscopic microwear analysis revealed predominantly fine wear features with numerous small pits and less abundant fine scratches as principal components. Almost all analyzed facets bear some coarser microwear features, such as coarse scratches, large pits, puncture pits and gouges pointing to episodic feeding on harder food items or exogenous effects (contamination of food with soil grit and/or dust), or both. 3D surface texture analysis indicates predominantly fine features with large void volume, low peak densities, and various stages of roundness of the peaks. We interpret these features to indicate consumption of food items with low to moderate intrinsic abrasiveness and can exclude regular rooting, digging or caching behavior. Possible food items include plant vegetative parts, plant reproductive structures (seeds and seed-bearing organs), and invertebrates (i.e., insects). Although the tritylodontid tooth morphology and auto-occlusion suggest plants as the primary food resource, our results imply a wider dietary range including animal matter.

Stubby versus stabby: A preliminary analysis of canine microwear in primates: Implication for inferring ingestive behaviors

“…As a final note, this study also reiterates the notion that feature‐based analyses still have a place in dental microwear investigations. Indeed, several researchers have begun to combine texture and feature analyses (e.g., Kalthoff et al, 2019; Schulz et al, 2013; Ungar, et al 2021). While feature‐based analyses are more time intensive and subject to observer measurement error (e.g., Grine et al, 2002), taking and averaging multiple measurements of the same surfaces helps minimize the noise and allow the signal to rise above it.…”

“…Following Schulz et al (2013), Kalthoff et al (2019), andUngar et al (2021), both microwear feature Ungar, 1995) and microwear texture analysis (Ungar et al, 2003, et seq. ) were employed in this study.…”

Post-mortem enamel surface texture alteration during taphonomic processes—do experimental approaches reflect natural phenomena?

“…Dental microwear texture analysis (DMTA) is a common and well-established proxy for reconstructing diet and food properties in extant and extinct vertebrates ( Scott et al, 2005 ; Merceron et al, 2007 ; Ungar et al, 2003 ; Ungar et al, 2020 ; Ungar, Merceron & Scott, 2007 ; Ungar, Grine & Teaford, 2008 ; Scott et al, 2009 ; Schulz, Calandra & Kaiser, 2010 ; Winkler et al, 2013 ; Winkler et al, 2016 ). It has been successfully applied to terrestrial large and small mammals ( Merceron & Madelaine, 2006 ; Calandra et al., 2012 ; Purnell et al, 2013 ; Kubo et al, 2017 ; Schulz-Kornas et al., 2019 ), including (semi-) aquatic mammals ( Purnell et al, 2017 ; Bethune et al, 2019 ), but also non-mammalian taxa like lepidosaurs ( Bestwick, Unwin & Purnell, 2019 ; Winkler et al, 2019 ), mammal-like reptiles ( Kalthoff et al, 2019 ), and fish ( Purnell & Darras, 2016 ). Microwear and microwear texture are shown to be powerful proxies for oral behaviour and ingesta-intake in general; however, analyses can be biased by post-mortem surface alteration resulting in enamel loss ( King, Andrews & Boz, 1999 ; Dauphin et al, 2018 ).…”