【古生物学】触覚感度の高い感覚器を持つ新種のティラノサウルス

A new species of tyrannosaur dinosaur is described in a paper in Scientific Reports this week. By analysing the texture of the facial bones of the new species - Daspletosaurus horneri - and other tyrannosauroids, the authors suggest that the face of tyrannosaurs was covered in a scaly protective layer with a high degree of tactile sensitivity, similar to crocodylians.

Thomas Carr and colleagues report the identification of a new species of tyrannosaur dinosaur from the Late Cretaceous (approximately 100-66 million years ago) from Montana and estimate that D.horneri was approximately nine metres long and 2.2 metres tall.

By examining the topography of the facial bones, the authors attempted to assess the type of soft tissue that may have covered the face of D.horneri. They found that the subcutaneous texture was coarse and showed a hierarchy of different textures. In order to identify the tissue that produced this surface, the authors compared their findings to crocodylians and five species of birds, and suggest that the face of tyrannosaurs was covered with flat scales.

Given the nearly identical arrangement and density of foramina (holes in bone through which nerves and blood vessels pass) to crocodylians, the authors infer that tyrannosaurids possessed integumentary sensory organs to transmit sensory information from the facial skin, as seen in crocodylians. They suggest that, given the similarities to crocodylians, this highly sensitive facile tactile system may have helped tyrannosaurids in prey capture, and object identification and manipulation.