A pathological scapula in a mosasaur from the upper Maastrichtian of Antarctica: Evidence of infectious arthritis and spondyloarthropathy

Abstract

We describe infectious arthritis and spondyloarthropathy in a juvenile mosasaur recovered from theupper Maastrichtian of Antarctica, representing thefirst report of a skeletal pathology of a mosasaurfrom the southern hemisphere. Macroscopic examination of the scapula revealed a remodelled, deeplyexcavated and expanded gleno-humeral joint with adjacent linear disruption. X-ray examinationrevealed a deep excavation expanding the glenoid fossa, with disorganized subchondral bone and a focalspherical defect. The individual did not continue to grow for a long time after the appearance of thelesion. Although not directly related to the mosasaur death, this condition may have contributed to thedemise of the animal by reducing its effectiveness at obtaining food or increasing susceptibility to fataldisease, additional injury, or even predation.