TMP 1978.004.0001, two lambeosaur proximal caudal vertebrae (close to where the tail attaches with the main body) and their associated chevron from Dinosaur Provincial Park. The chevron is fused to the two vertebrae via a large oval-shaped mass at the point of connection between the two vertebrae, resembling spondyloarthropathy. This specimen may preserve a severe form of arthritis known as ankylosing spondylitis which causes vertebrae to fuse, resulting in a rigid and inflexible motion between the two bones.