Boyer diss 2009 1046..

have been present in the complete column. From a small dataset in Table 4.24, it can be
seen that standard numbers of vertebrae among a few scansorial sciurids, generalized
euprimates, scandentians, and some marsupials are seven cervical, 12 thoracic, seven
lumbar, three sacral and 25 caudal vertebrae. However, there is a bit of variation in the
number of thoracic, lumbar, and sacral vertebrae, and a lot of variation in the number of
caudals. UM 87990 preserves five cervical (Fig. 4.41), 12 thoracic (Fig. 4.42), and six
lumbar vertebrae (Fig. 4.43). For descriptive and comparative purposes, I reconstruct the
plesiadapid vertebral column as having seven cervical, 13 thoracic and seven lumbar
vertebrae (Table 4.24). The sacrum is complete with three vertebrae (Fig. 4.44). There is
no way to generate a constrained estimate of the number of caudal vertebrae from the
comparative data. However, there are 17 preserved caudal vertebrae and at least three
specific anterior positions are missing (Fig. 4.45). There were thus at least 20 caudal
vertebrae.
Vertebral column comparisons.—Comparisons of P. cookei’s vertebral column to
those of other taxa were made using four different principal coordinate analyses on
Euclidean distance matrices relating cases in the sample (Fig. 4.46). Variables for these
analyses were calculated from craniocaudal length measurements of the vertebrae and
vertebral column. More specifically, as discussed in the Methods section, “size free”
shape variables were created as natural log ratios of each measurement to the geometric
mean of all measurements included for a specimen in a given analysis. The first analysis
(Fig. 4.46A) uses measurements and/or estimates (in the case of some incomplete fossil
specimens) of five vertebral segment lengths from Table 4.24. The second (Fig. 4.46B)
uses all available vertebrae lengths in the column of P. cookei up to Ca10 (31
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