A bitten skull of Tylosaurus kansasensis (Squamata: Mosasauridae) and a review of mosasaur-on-mosasaur pathology in the fossil record

Abstract

Aside from large sharks such as Cretoxyrhina mantelli, there are no other marine species known from the Late Cretaceous which could challenge the role of mosasaurs as apex predators. From the evidence of the injuries observed on mosasaur remains, however, it is likely that they occasionally fought with or were attacked by other mosasaurs. Sometimes the injuries incurred in this combat were non-fatal and show evidence of healing prior to the death of the mosasaur, while in other instances, the injuries were apparently fatal. The well-preserved skull and lower jaws of the holotype specimen of Tylosaurus kansasensis (FHSM VP-2295) in the collection of the Stemberg Museum of Natural History exhibit readily visible punctures and gouges on the frontal, left prefrontal, right dentary and right articular that are attributable to the bite of a larger mosasaur. These deep and unhealed bite marks on the skull, as well as a possible broken neck, suggest that this individual died from injuries received when its skull was bitten and possibly crushed by another mosasaur.