Earliest Evidence Of Bone Lesion In A Metatherian

Although metatherians are known since Early Cretaceous, there is little evidence of bone lesions in this extremely diverse mammalian clade. Here, we report an asymptomatic and benign condition namedtorus mandibularisin an incomplete right dentary assigned toPatene simpsoni, a basal sparassodont from the early Eocene of Sao Jose de Itaborai Basin, Brazil. This report represents the oldest evidence of bone lesion in a Metatheria, as well as the first occurrence oftorus mandibularisin a nonhuman fossil. The proposed diagnosis was based on location and external appearance of the bone overgrowth.