The neurocranium of the Paleozoic ‘chipmunk ray’ Tamiobatis vetustus Eastman, 1897. A brief history of research and new morphological observations based on computerized tomography

The holotype specimen of Tamiobatis vetustus Eastman, 1897 (NMNH 1717) was the first essentially complete, three-dimensional Paleozoic chondrichthyan braincase known to science. Here, it has been investigated using computerized tomography (CT), revealing its internal morphology for the first time, including the intracranial and labyrinth cavities, internal courses of nerves and blood vessels, plus several remarkable new features which are described here. Some supposedly morphological features of the neurocranium are reinterpreted as bilaterally symmetrical taphonomic artifacts.