A1, surface rendering generated from Synchrotron Radiation X-ray microtomographic slices. Part of the dorsal surface of the interorbital plate removed (dotted line). Dark grey, internal surface of the floor of the endocranial cavity and interorbital plate; light grey, external surface of the braincase. A2, corresponding drawing. B1, surface rendering generated from Synchrotron Radiation X-ray microtomographic slices. Dark grey, internal surface of the endocranial cavity and interorbital plate; light grey, external surface of the braincase. B2, corresponding drawing. Scale bar = 0.5 cm. Abbreviations: cora, canal for the orbital artery. See Figs. 3, 4, 6 and 7 for other abbreviation.