Data from: Dietary constraints of phytosaurian reptiles revealed by dental microwear textural analysis

Phytosaurs are a group of large, semi-aquatic archosaurian reptiles from
the Middle–Late Triassic. They have often been interpreted as carnivorous
or piscivorous due to their large size, morphological similarity to extant
crocodilians and preservation in fluvial, lacustrine and coastal deposits.
However, these dietary hypotheses are difficult to test, meaning that
phytosaur ecologies and their roles in Triassic food webs remain
incompletely constrained. Here, we apply dental microwear textural
analysis to the three-dimensional sub-micrometre scale tooth surface
textures that form during food consumption to provide the first
quantitative dietary constraints for five species of phytosaur. We
furthermore explore the impacts of tooth position and cranial robusticity
on phytosaur microwear textures. We find subtle systematic texture
differences between teeth from different positions along phytosaur tooth
rows, which we interpret to be the result of different loading pressures
experienced during food consumption, rather than functional partitioning
of food processing along tooth rows. We find rougher microwear textures in
morphologically robust taxa. This may be the result of seizing and
processing larger prey items compared to those captured by gracile taxa,
rather than dietary differences per se. We reveal relatively low dietary
diversity between our study phytosaurs and that individual species show a
lack of dietary specialisation. Species are predominantly carnivorous
and/or piscivorous, with two taxa exhibiting slight preferences for
‘harder’ invertebrates. Our results provide strong evidence for higher
degrees of ecological convergence between phytosaurs and extant
crocodilians than previously appreciated, furthering our understanding of
the functioning and evolution of Triassic ecosystems.