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maxillary divisions. In this case, no foramen devoted solely to the maxillary division of
the trigeminal would have existed, and thus a foramen rotundum did not exist.
My observations of the original material lead me to conclude that there is no
foramen rotundum [i.e., what Russell called the “t.d.a.” is in fact the suboptic foramen, as
Kay et al. (1992) suggest]; however, the evidence for this conclusion must partly be
gleaned from MNHN CR 965 and is discussed below. One point that can be made on
MNHN CR 125, however, is that the “suboptic foramen” appears to be entirely within the
orbitosphenoid, unlike the superior orbital fissure, which falls between the orbitosphenoid
and alisphenoid. Notably, MNHN CR 125 has a different small foramen just posterior to
the optic foramen and anterior to the “sphenorbital fissure.” This small foramen could
also plausibly be considered a superior orbital fissure because it appears to open
anteriorly through the junction of the alisphenoid and orbitosphenoid (Fig. 2.20: 93).
However, this foramen is not bilaterally present and it is absent from MNHN CR 965,
suggesting that it is simply another, variably present hole. It does, however, serve to
reveal the alisphenoid/orbitosphenoid suture, which spans between said foramen (93) and
the sphenorbital fissure (90).
Interpretations of foramina of the basicranium have also been contentious. As
discussed in the introduction, Bloch and Silcox (2001) implied that this specimen was
lacking evidence of a posterior carotid foramen. However, Figure 2.19B’ shows the
posterior carotid foramen perpendicular to its canal and illustrates its caliber and shape.
There is no doubt regarding the interpretation of this feature given the consistency of its
presence in other specimens of this species, as well as in other species (see above). The
canal leading from the posterior carotid foramen through the base of the posterior septum
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