Figure 3 in Evolution and functional morphology of the frontal sinuses in Bovidae (Mammalia: Artiodactyla), and implications for the evolution of cranial pneumaticity

Figure 3. Digital reconstructions and computed tomography (CT) slices of bovid skulls, illustrating the frontal sinuses and related anatomy, in Nanger granti (A–C; YPM 11526), Cephalophus leucogaster (D, F; AMNH 52802), and Raphicerus campestris (E, G; YPM 10276). In C, note the distinct frontal sinus that invades the trabecular bone, is bounded by cortical bone on all sides, and is distinctly separated from the olfactory turbinals below. This contrasts with the condition in E, in which a distinct recess above the olfactory turbinals is pressed into the frontal bone, but does not actually invade the trabecular bone. In D, no recess exists at all, and the space beneath the frontals is entirely occupied by turbinals. The dashed lines in A, F, and G indicate the approximate positions of the coronal CT slices in C, D, and E, respectively. The boxed areas in A and B indicate the region of the skull that has been rendered partially transparent in order to visualize the anatomy of the frontal sinuses. Scale bars: 5 cm.