Several occurrences of osteomyelitis in dinosaurs from a site in the Bauru Group, Cretaceous of Southeast Brazil

This study investigates the occurrence of osteomyelitis in non-avian dinosaurs, focusing on the Ibirá locality, a site with a high incidence of this pathological condition. We analyzed six new osteopathic sauropod specimens from the Upper Cretaceous of Brazil. The results revealed a relationship between infection and bone remodeling, denoted by various manifestations of reactive bone neoformation, including periosteal reaction. Healing tissues were not identified, which implies that the individuals died when the infection was still active. We described distinct manifestations of osteomyelitis with periosteal bone neoformation: (1) periosteal reaction within small circular protrusions; (2) ellipsoid protrusions in a fingerprint pattern; (3) enlarged protrusions both in height and area. This study underscores the importance of examining pathological conditions in extinct species to enhance our understanding of their physiology and interactions with their ancient environments.