New palaeopathology cases of Allosaurus fragilis (Dinosauria: Theropoda)

Here, we describe a pathological sub-adult theropod dinosaur from the Late Jurassic Morrison Formation in Dana Quarry, Wyoming, U.S.A. It exhibits multiple pathologies, involving three dorsal vertebrae, the right scapula and coracoid, and apparent pathology of the left scapula. The fourth dorsal vertebra has four irregularly shaped growths on the vertebral arch. The eighth and ninth vertebrae are fused. The scapulocoracoid joint has an obvious deformity. The distal part of the right scapula is more rounded than normal. The left scapula has a depression on the lateral blade. These pathologies can be identified as follows: the fourth dorsal vertebra is possibly neoplastic or exhibiting compensatory hyperplasia; the eighth and ninth vertebral and the right scapular pathology are consistent with spondyloarthropathy. Diagnoses considered for the left scapula pathology are infections, trauma or unknown. The animal survived the pathologies, which are unlikely the cause of its death. This specimen represents the first known occurrence of spondyloarthropathy in a theropod.