Figure 6 in New data on the braincase of the aetosaurian archosaur (Reptilia: Diapsida) Stagonolepis robertsoni Agassiz

Figure 6. Summary of hypothesis of suchian braincase evolution, based on phylogeny presented in Fig. 5B and morphological and phylogenetic evidence presented in text. Key caveats include the omission of ornithosuchians and Gracilisuchus stipanicicorum from consideration. Schematic figures depict the left otic region in lateral view. Some proposed braincase synapomorphies are shown on some branches – for a broader context and consideration of more characters, see Gower (2002b). Sphenosuchus redrawn from Walker (1990), Crocodylus redrawn from Gower & Weber (1998). For Crocodylus, only the detail of the ventral ramus of the opisthotic is shown. The metotic foramen does not exist because the metotic fissure is subdivided so that the external foramina for the vagus nerve (X) lies far posterior to the ventral ramus of the opisthotic. External foramina for the hypoglossal nerve (XII) are indicated by solid black dots. cr = cochlear recess; lcs = loop closure suture of ventral ramus of the opisthotic; pr = prootic. Diagrams not drawn to scale.