Complex neurovascular system in the dentary of <i>Tyrannosaurus</i>

The morphology of the neurovascular canal in the jaw has been analysed in several fossil reptiles, including theropod dinosaurs. However, the details of the neurovascular canal in the dentary of theropods have not been fully elucidated. In this study, we described the well-preserved dentary of Tyrannosaurus rex, analysed the morphology of the neurovascular canal in the dentary using computed tomography techniques, and compared its distribution pattern with other dinosaurs and extant crocodiles. The results show that the neurovascular canal in the dentary of Tyrannosaurus exhibits a rather complex branching amongst the sampled dinosaurs, and that the complexity is comparable to that of extant crocodilians. The complexity of the canal branching is likely related to the high tactile sensitivity of the dentary, suggesting that the jaw tip of Tyrannosaurus may have played an essential role as a sensitive tactile sensor.