Boyer diss 2009 1046..

provides measurements of these and other features. Table 2.6 provides natural log ratio
variables quantifying their shape (see table 2.4 for descriptions of variables). Although
sample sizes are too small for statistical confidence of any sort, it is interesting to note
that P. tricuspidens has substantially proportionally narrower nasals (Table 2.6: N/GM),
wider premaxillae (Table 2.6: N/Pmx, Pmx/GM), and a more tubular external auditory
meatus (Table 2.6: EAM-S) than any of the other plesiadapids. Thus other plesiadapids
are not as distinctive in these features as is P. tricuspidens. Another interesting
difference between P. tricuspidens and other plesiadapids is its proportionally larger
glenoid fossae (Table 2.6: Gld/GM). Finally, it appears that the largest plesiadapids
(mainly P. tricuspidens) have the proportionally shortest cochleae (Table 2.6: Cl/GM),
smallest petrosals (Table 2.6: Pcsa/GM) and smallest fenestra vestibulae (Table 2.6:
ac/GM).
NEW EVIDENCE BEARING ON THE COMPOSITION OF THE PLESIADAPID
BULLA
As mentioned in the introduction, the morphological prediction for a non-petrosal
bulla is the presence of a suture separating the bulla from the pars cochlearis of the
petrosal bone. However, whether and when this suture would have been obliterated by
remodeling, and what the physical evidence for its presence should look like have not
been outlined. A preliminary survey of mammals with basicranial forms similar to those
of plesiadapids and basal euprimates includes several rodents, treeshrews, and two
paromomyids. These taxa have large inflated bullar cavities with bony septa buttressing
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