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Head-biting behavior in theropod dinosaurs: paleopathological evidence /

Source: OAI

ABSTRACT Cranial material of Sinraptor dongi (Upper Jurassic, Xinjiang, China), Gorgosau- rus libratus, Daspletosaurus torosus (Upper Cretaceous, Alberta, Canada), and other large theropod dinosaurs exhibit similar paleopathological anomalies indicative of aggressive in- tra- or interspecific biting. Tooth strike trauma includes osseous lesions caused by solitary or multiple tooth punctures, or by dragging or gouging the tooth tips across the surfaces of cranial elements. Many of these lesions were undergoing active healing at the time of death. One isolated tyrannosaurid dentary bears a broken off and embedded tooth tip of another ty- rannosaur. Comparison with unhealed large theropod toothmarks on prey bone suggests that sublethal wounds of these types were caused by other large theropods, possibly rival conspecifics. This may indicate aggressive head or face-biting behavior in certain theropod families. Other associated traumatic osteopathy typified as localized rib and fibula fractures were observed but cannot be directly correlated with violent intra- or interspecific behavior. Healed and healing bite wounds of the head may be related to a number of factors. Establish- ment of dominance within a pack and territorial behavior are considered as two of the most likely causes. Study of paleopathologies is demonstrated to be a useful tool for understand- ing dinosaur behavior.

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