Teeth histological images Guarinisuchus munisi

Guarinisuchus munizi is an extinct Paleocene crocodyliform from the Maria Farinha Formation in the Paraíba Basin, Brazil. It belongs to the family Dyrosauridae, a lineage known for surviving the Cretaceous–Paleogene mass extinction and adapting to marine and freshwater environments. Renowned for their locomotor versatility and diverse feeding strategies, dyrosaurids can provide key insights into post-extinction ecosystems. Although macromorphological evidence suggests a primarily piscivorous diet for G. munizi, the dietary flexibility of this species remains poorly understood. Gaining insights in its dietary range is crucial for reconstructing trophic dynamics and ecological resilience in early Paleocene ecosystems. In this study, we provide the first histological analysis of the dentition of G. munizi, addressing gaps in the existing literature relating to dietary and ecological interpretations. Ten isolated teeth from the Poty Quarry, Maria Farinha Formation, were analyzed using standard histological techniques, revealing enamel thicknesses ranging from 0.05 to 0.12 mm. Observations of the thin enamel layers suggest adaptations for cutting soft tissues, supporting a specialized piscivorous diet. Conversely, the presence of thicker enamel layers indicates dietary versatility, potentially including hard-shelled prey or plant material. These findings advance our understanding of the feeding ecology of G. munizi and highlight its adaptability to varied environmental conditions in freshwater and marine ecosystems. Comparative analyses reveal similarities in dental microstructure with other taxa, including Mariliasuchus and Baurusuchus. Our findings demonstrate the value of dental histology in reconstructing the dietary and ecological roles of extinct crocodyliforms, thus providing a foundation for further investigations into dyrosaurid paleoecology.