Fig. 4 in Earliest Eutherian Ear Region: A Petrosal Referred to Prokennalestes from the Early Cretaceous of Mongolia

Fig. 4. Right ear regions in ventral view, with major arteries, veins, and nerves. A, The basicranium of the monotreme Ornithorhynchus anatinus, modified and redrawn from Wible and Hopson (1995: fig. 4B). B, The petrosal of the prototribosphenidan Vincelestes neuquenianus, modified and redrawn from Rougier et al. (1992: fig. 3C). C, The petrosal of the marsupial Didelphis virginiana, modified and redrawn from Wible and Hopson (1995: fig. 5A). D, The basicranium of the placental Solenodon paradoxus, modified and redrawn from McDowell (1958: fig. 7B). The opossum has an internal carotid artery (not shown), but it does not contact the petrosal, which also occurs in the platypus.