Earliest evidence of bone lesion in a metatherian

ABSTRACT

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 named torus mandibularis in an incomplete right dentary assigned to Patene simpsoni, a basal sparassodont from the early Eocene of São José de Itaboraí Basin, Brazil. This report represents the oldest evidence of bone lesion in a Metatheria, as well as the first occurrence of torus mandibularis in a nonhuman fossil. The proposed diagnosis was based on location and external appearance of the bone overgrowth.

KEYWORDS:

• Patene simpsoni
• sparassodont
• torus mandibularis
• Palaeogene
• Itaboraí Basin
• Brazil

Acknowledgments

We would like to express our gratitude to D.D.R. Henriques, and J.A. Oliveira (Museu Nacional/UFRJ), R.R. Machado (DNPM/RJ), A. Kramarz, and S.M. Alvarez (Museo Argentino de Ciencias Naturales Bernardino Rivadavia), and F.J. Goin (Museo de La Plata) for allowing access to the studied specimens. We thank L.M. Carneiro (UFPE), who provided helpful information about South American metatherians. We are also grateful to the two anonymous reviewers of this manuscript for their important contributions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [#310101/2017-4]; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro [#E-26/202.829/2018,202.496/2019].