Boyer diss 2009 1046..

tricuspidens postcrania in the Chapter 4 illustrate that the two taxa are also nearly
identical in their long bone diameters. The fact that so many skeletal elements suggest
equivalent sizes for these two taxa is taken as strong evidence that P. cookei and P.
tricuspidens are of equivalent size, despite differences in tooth sizes.
In contrast, the P. cookei skull is much larger than known skulls of other
plesiadapid taxa. Using the direct comparisons method, it is 154% the size of that of
Plesiadapis anceps (YPM-PU 19642), 170% the size of Nannodectes gidleyi (AMNH
17388), 176% the size of Pronothodectes gaoi (UALVP 46685), and 210% the size of
Nannodectes intermedius (USNM 309902) (Table 3.3).
The accuracy of these estimates for smaller plesiadapids can be checked by
comparison to measurements of the skull, teeth and skeleton of P. insignis (Gingerich,
1976). Gingerich measured the skull length of P. insignis at 50 mm (Gingerich, 1976:
p.35, table 6). The measurements of its teeth are in the range of those of N. intermedius.
(Gingerich 1976: compare p.35, table 5 with p.105, table A-3) Furthermore, its
postcrania are nearly identical in their lengths to those known of N. intermedius (see
Chapter 5). I would thus predict the skull length of N. intermedius to be the same as that
of P. insignis. In fact, dividing the estimated length of P. cookei’s skull by 210% (=105.8
mm/2.10) gives an estimated length of 50.4 mm for N. intermedius.
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