Boyer diss 2009 1046..

is not convoluted like many other sutures; however, the contact between these particular
bones frequently looks this way in various other taxa (e.g., tenrecs). Furthermore, two
features (only one could be photo-documented) of this contact strongly suggest it is a
suture: (1) the form of the discontinuity between the alisphenoid and orbitosphenoid is
revealed by the absence (i.e., broken condition) of the orbitosphenoid in the region of
interest. Instead of appearing “crack-like” and planar, the discontinuity is dished like a
sutural contact (Fig. 2.24: 102). (2) Even though the discontinuity is not convoluted like
other sutures, it is still more complex than would be expected for a crack created by
brittle deformation. Identification of this final suture helps interpret cranial foraminal
patterns. Having recognized this suture on MNHN CR 965, it becomes apparent that it
has a slightly different course than that preserved on the left side of MNHN CR 125
connecting foramina 90 and 93 (Fig. 2.20D’). The latter suture would likely have
resulted in the orbitosphenoid forming most of the medial wall of the sphenorbital fissure.
Cranial foramina.— Foramina for the trigeminal nerve’s mandibular division
(Figs. 2.22, 25: 103), for its combined maxillary and ophthalmic divisions (Figs. 2.22-25:
104), and for the optic nerve (Figs. 2.22, 24-25: 105) are clearly visible and traceable to
endocranial space. There are a number of small foramina representing sinus drainage
from the lateral aspects of the alisphenoid and the lateral aspect of the orbitosphenoid
(Fig. 2.23, 24: 106). These cannot be mistaken for cranial nerve foramina because they
are not bilaterally present in some cases or do not lead to the endocranium in other cases.
This is also true for the “suboptic foramen” located posteroventral to the optic foramen
(Figs. 2.22, 24: 107). It appears to lead into the trabecular space of the orbitosphenoid
and probably communicates directly with the blood sinus foramina on the opposite side.
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