Non-occlusal dental microwear texture analysis of a titanosauriform sauropod dinosaur from the Upper Cretaceous (Turonian) Tamagawa Formation, northeastern Japan

Abstract

Sauropod teeth from the Tamagawa Formation of Kuji Group, northeastern Japan, were described and diet of the Kuji sauropod was inferred by dental microwear texture analysis (DMTA). The morphology and slenderness index (SI) of Kuji sauropod teeth indicate they belong to a titanosauriform somphospondyli sauropod and thus confirm the existence of a titanosauriform sauropod at the coastal area of East Asia during the late Turonian. Dental microwear texture (DMT) of the Kuji sauropod is compared with extant lepidosaurs with known dietary preferences, indicating a higher degree of oral food processing in the Kuji sauropod than in extant lepidosaurs. The Kuji sauropod fed on materials less resistant and softer than molluscan shells or exoskeletons of insects and likely relied on plant materials. Considering what is known about the paleoflora of the Tamagawa Formation, the most likely diet was ferns and gymnosperms. These initial results encourage future applications of DMTA to various sauropods, which could help to reveal the evolution of their feeding ecology and whether the increase of SI is associated with dietary change.