Narial

Data on turtles and mammals were collected from the literature, numerous dried skulls, and dissection notes and accumulated experience; the stereoradiographic techniques were not used for these clades partly because turtles and mammals are less relevant for inferences about dinosaurs but mostly because the narial anatomy of turtles and mammals clearly dictates the rostral position of the fleshy nostril relative to the bony nostril.

The asymmetry of the bones too is remarkable, although this is characteristic of all the catodon whales, especially as regards the bones of the anterior narial passages, the left of which is very much larger than the right.