Palaeontologists from the Museum für Naturkunde Berlin, a radiologist from the Charité Hospital and a veterinarian of the Institut für Zoo- und Wildtierforschung Berlin published an extraordinary discovery of a fossil reptile that suffered from an inflammatory bone disease in the current issue of the scientific magazine PlosOne. The scientists found deformed vertebrae of the phytosaur “Angistorhinopsis ruetimeyeri” in the collection of the museum that can be traced back to a painful bone disease called spondyloarthropathy.
The approximately 220 million years old remains were found in Halberstadt, central Germany, and belong to an amphibious, fish-eating reptile that superficially resembled a crocodile and is distantly related to dinosaurs. Although phytosaurs are commonly found in Triassic sediments, bone injuries have rarely been reported and are restricted to the skull. The finding in the Berlin museum shows clear signs of an inflammatory bone disease that is evident at different locations of the vertebral column.
Determination of the cause for the vertebral deformations and even an assessment of their temporal progression was possible by the investigation of the fossil bones via X-ray computed tomography. Three different pathologic observations can be made in the vertebral column of the phytosaur: 1) fusion of two thoracic vertebral bodies by new bone formation within the vertebral joint; 2) fusion and conspicuous shortening of last dorsal and first sacral vertebrae; and 3) destruction of the front articular surface of the last dorsal vertebra. Observations 1–3 can most plausibly be attributed to one disease: spondyloarthropathy, an aseptic inflammatory process in which affected vertebrae show typical types of new bone formation and erosion of bone covered by cartilage. The extremely eroded last dorsal vertebra shows impressively that this painful disease must have started already in the early life of the phytosaur and affected it throughout its entire life span without causing directly its death. Fossil evidence of inflammatory bone diseases in reptiles is still exceptional what makes this case an important discovery. In contrast to fossil and extant reptiles, spondyloarthropathy in humans is not unusual (a well-known variant is Bechterew’s disease) but can most often be treated quite well and stopped by new medicines.