Testing intra-individual variation in dental microwear texture of Omeisaurus maoianus and preliminary interspecific comparisons of sauropodomorphs

Throughout their long evolutionary history, sauropodomorph dinosaurs developed various craniodental adaptations against a background of changing floras. While their diets and niche partitioning have been studied using dental microwear analysis, the scarcity of well-preserved skulls has necessitated the frequent use of isolated teeth. Here, we test the reliability of data derived from isolated teeth by examining intra-individual variation in three-dimensional dental microwear texture (DMT) using a rare, complete skull of Omeisaurus maoianus . Additionally, we performed a preliminary comparison of DMT across six sauropodomorph taxa spanning from the Early Jurassic to the Late Cretaceous. Our results revealed no significant differences in DMT along the tooth rows of O. maoianus related to tooth position. Although a subtle trend toward rougher DMT was observed in more distal teeth, these findings tentatively validate the use of isolated teeth for dietary reconstruction. Inter-taxonomic comparisons identified significant differences between the basal sauropodomorph Yunnanosaurus and more derived sauropods ( Camarasaurus , Euhelopus , and Omeisaurus ), with the former having a smoother DMT than the latter. This likely reflects a dietary shift toward tougher and more fibrous plant materials during the transition from basal sauropodomorphs to eusauropods. While this preliminary analysis did not detect further differences among derived sauropods—potentially due to limited sample sizes—future DMTA studies with expanded datasets are expected to reveal more nuanced dietary shifts corresponding to environmental changes.