Spinal and rib osteopathy in Huehuecanauhtlus tiquichensis (Ornithopoda: Hadrosauroidea) from the Late Cretaceous in Mexico

Osteopathy from derived hadrosauroids has been extensively studied. However, little work has been done in the basal members of this group. Only two brief notes have recorded three examples of osteopathy in the basal hadrosauroids in Bactrosaurus, Gilmoreosaurus and Jeyawati. In the present manuscript, we found in the holotype of the basal hadrosauroid Huehuecanauhtlus tiquichensis (IGM 6253) from Mexico two dorsal ribs and a dorsal vertebra with unusual pathologic conditions. The injuries are described as possible premortem or perimortem anterior rib fracture, associated with a singular sclerosis and costo-vertebral ankyloses which probably originated by spinal and rib osteomyelitis. The vertebral lesion caused direct damage to the nervous system and possible back pain. This study represents the first study of palaeopathology in a Mexican hadrosauroid in which the bone abnormalities are extensively compared with previous studies and described in detail, their origins are interpreted, and the health implications for the individual are considered.