Boyer diss 2009 1046..

the posterior septum, a deeply incised canal stems anterodorsally from an apparent
foramen (Fig. 2.16C: g4). Both promontoria also have a groove that crosses from medial
to lateral, approaching the s2. It thus appears to be the g3 groove. However, the
morphology of this groove on the left side looks suspiciously as though it could be due to
postmortem damage (i.e., like a crack, the edges of which have become beveled by
weathering).
Medial tympanic processes flare out from the medial side of both promontories.
These processes measure 1.5-1.6 mm in width, on average. The stylomastoid foramina
are preserved on both sides (Fig. 2.16: 64) and circular. They measure roughly 0.80-0.90
mm in diameter. Interestingly, there is a foramen wedged medial to these facial nerve
foramina, and lateral to the posterodorsal base of the posterior septum on both sides (Fig.
2.16B, C: 65). This foramen appears to lead to a canal and may have transmitted the
internal carotid plexus. If so, it means that the route of the internal carotid plexus has
migrated dorsally, and slightly laterally from its position in other plesiadapids. The
diameter of this possible posterior carotid foramen is about 0.29 mm, comparable to the
posterior carotid foramen and internal carotid groove (g1) on other plesiadapids (Table
2.3).
Occipital.— The left occipital condyle and the jugular process are preserved (Fig.
2.15: 66, 67). The dorsoventral height of the condyle is roughly 2.8 mm; the mediolateral
width is 2.5 mm. The jugular process projects 2.64 mm laterally from the edge of the
condyle. The mediolateral width of the foramen magnum (Fig. 2.15: 68), although
possibly slightly distorted owing to dorsoventral crushing, is 6.84 mm.
57