3D skull models showing marked reduction in CP morphology in taxa heavily reliant on non-olfactory sensory modalities.

(a), CP loss viewed in nasal morphology of bottlenose dolphin (Tursiops truncatus), which uses echolocation. Pink: Single pair of foramina connecting ethmoid area of the nasal passage to the cranium. Inset, magnification of foramina. (b-c), Impact of orbit size on CP size constraints, contrasting the tarsier (Tarsius syrichta) and armadillo (Dasypus novemcinctus). (b), Tarsier, a visually-specialized nocturnal primate with enlarged, forward facing orbits, has reduced olfactory anatomy. Red: CP squeezed between convergent orbits. (c), By contrast, the armadillo’s large CP (red) fills the space between small, laterally oriented, wide set orbits. 3D models constructed with Mimics and 3-matic software from high-resolution CT scans.