Boyer diss 2009 1046..

Description of new cranial material of Pronothodectes gaoi
UALVP 46685 is a highly deformed skull of Pronothodectes gaoi. Heavy wear
on P 4 and a concealed M 1-3 (revealed with HRxCT) demonstrate it to be an
ontogenetically old individual. The alveolar processes of the maxillae have been rotated
medially toward one another. The neurocranium has been rotated ventrally and folded
anteriorly so that the right glenoid fossa actually faces dorsally (Fig. 2.1), while the
basicranium has been translated anteriorly, ventral to the molar dentition, thereby
concealing these teeth (Fig. 2.2). Finally, the convoluted specimen was flattened
dorsoventrally. Due to this deformation, many sutures, foramina, and morphological
details are obscured. Even so, the specimen provides a large amount of new information
about cranial morphology in Pronothodectes that can be compared to that of other
plesiadapids in order to assess patterns of change that may have characterized the
family’s evolutionary history.
Nasal.—The nasals contact only the premaxillae (Fig. 2.1: 1) and frontals (Fig.
2.1: 2). They have distinct sutures with the premaxillae but contact with the frontal is
more difficult to discern due to crushing and missing bone. It is apparent that the nasals
have a mediolateral width that is fairly constant from anterior to posterior (average
unilateral width = 2.6 mm). They appear to have extended posteriorly to the level of P 3-4 .
Premaxilla and Premaxillary Dentition.—Both premaxillae are preserved. The
right side has suffered less damage than the left side (Figs. 2.1-3). The nasal (Fig. 2.1: 1),
maxillary (Fig. 2.1-3: 3) and frontal (Fig. 2.1: 4) sutures are visible. The suture with the
nasal is straight and simple (Fig. 2.1: 1). The suture with the right maxilla is observable
just posterior to I 2 (Figs. 2.2, 3: 3). It is convoluted, but runs dorsoventrally for ~3 mm
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