First documentation of a greenstick fracture in the fossil record. Possible gout also noted in Arkansaurus fridayii

Abstract

ABSTRACT Examination of a cast of the newly recognised Arkansas state dinosaur, Arkansaurus fridayii, revealed abnormal pedal features. As casts do not always faithfully reproduce bony alterations and often lack sufficient resolution for delineation of fine features, the original pedal elements were obtained and subjected to non-destructive microscopic examination to characterise the nature and identify the derivation of the macroscopically recognised pathology. A fracture event associated with tendon/ligament avulsion and possible gout was identified. The fractures were greenstick in nature, a variety not previously reported in dinosaurs. A spherical defect, characteristic of gout, was also noted. Trauma produced tendon/ligament avulsion greenstick fractures. Gout has previously been noted in tyrannosaurs, but these findings would be its first recognition in an orinthomimid.