Traumatic pathologies in the postcranium of an adult Allosaurus specimen from the Morrison Formation of the Howe Quarry, Wyoming, U.S.A.

Citation:
Evers, S., Foth C., Rauhut O., Pabst B., & Mateus O. (2013).  Traumatic pathologies in the postcranium of an adult Allosaurus specimen from the Morrison Formation of the Howe Quarry, Wyoming, U.S.A. . Journal of Vertebrate Paleontology, Program and Abstracts, 2013. 124.

Adult large-bodied theropods are often found with numerous pathologies. A large, almost complete, adult Allosaurus specimen (Sauriermuseum Aathal [SMA] 0005) from the Howe Quarry, Morrison Formation (Late Kimmeridgian–Early Tithonian), Wyoming, shows a number of pathologies. Pathologic bones include the left scapula, several left dorsal ribs, the right ischium, and a left pedal phalanx.
A complete, transverse fracture occurs in the proximal part of the left scapula. The distal fragment is displaced and distorted in relation to the proximal fragment. The fracture does not show a callus structure as expected for a healed injury, but some secondary osseous connection to the distal fragment is apparent at the rupture point of the proximal fragment, resulting in a weak attachment. This is consistent with the formation of a pseudoarthrosis, which occurs as a delayed healing response in fractures that lack adequate stabilizing and are subject to frequent movement.
The distal part of the left scapula is fractured incompletely and transversely. The bone around the fracture is slightly thickened and roughened. The fracture is at approximately the same level as a series of transversely fractured left dorsal ribs. The presence of calli around the rib fractures and the alignment of the scapula and rib pathologies suggest that all may have been caused by a single traumatic event. 
The right ischium suffered a complete, oblique fracture. Rough bone tissue covers the fracture on one side completely, while the other shows no sign of reactive growth.
A pedal phalanx has a hyperostosis at the dorsal and lateral sides of its proximal end, forming an ovoid callus, unlike the large irregular exostoses in phalanges of other Allosaurus specimens, including Museum of the Rockies specimen MOR 693 from the same quarry. The bone surface is roughened, but not rugose, and lacks lesions indicative for infections. This indicates bone resorption in an advanced healing stage of  the injury.
All the pathologies show signs of healing, suggesting that none of them directly caused the death of the individual. This again underlines that large-bodied theropods experienced frequent traumatic injuries during life, an indication of an active lifestyle as a predator.