FIG. 40 in Cranial Morphology And Phylogenetic Relationships Of Trigonostylops Wortmani, An Eocene South American Native Ungulate

FIG. 40. Transverse segments comparing vascular routes in mastoid region in Equus caballus AMNH M-204155 (A–E) and Tetramerorhinus lucarius AMNH VP-9245 (F–I) on this and facing page, each series in caudorostral order. Equus series: In A–C, sulcus for arteria diploetica magna/caudal meningeal artery (single asterisk) crosses lateral face of petrosal mastoid in a deep sulcus covered by overlying squamosal (thus forming posttemporal foramen, so-called mastoid foramen of equine anatomies). Artery's trackway is located below, but converges with, sulcus for temporal sinus in separate compartment. In D, at transverse level of external acoustic meatus, sulcus for artery enters short canal (canal Y) that penetrates dorsal surface of petro-