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

Abstract

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.

Keywords:

• Ankylosis
• costo-vertebral
• Dinosauria
• palaeopathology
• hadrosauroid
• osteomyelitis

Acknowledgements

Thanks to A. Shunemann de Aluja, L. Espinosa Arrubarrena, J. Alvarado Ortega, J. L. Tórtora and L. Romero Romero for their comments on the preliminary thesis work. Thanks to M. Bennami, M. R. Chavarría Martínez, R. Servín Pichardo, A. Amaya López, G. A. Ramírez Cruz, V. Valenzuela, J. L. Gudiño Maussan, D. Beltrán López, J. M. Contreras, for their help during the comparisons in the palaeontological collections. Thanks to M. Montellano Ballesteros and R. Molina for large amount of invaluable information on palaeopathology. Thanks to Aldi de Oyarzabal for the teaching and comments in the vertebrae illustration. Thanks to Cedillo, B. P. Miranda Torres, P. Bezaury, A. Sanabria, J. Albarrán López and the personnel of the Unidad PET/CT Ciclotrón of the Facultad de Medicina UNAM by performing the CT scans. Thanks to M. del C. Perrilliat-Montoya, J. Alvarado-Ortega and V. A. Romero (IGM) to allowing access to the Colección Nacional de Paleontología del Instituto de Geología, UNAM. The research funds were provided by the IN-216511-2 PAPIIT project. Thanks to B. M. Rothschild, the Language Editing Services of ELSEVIER and the anonymous reviewers who improved the manuscript with their written comments.