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specimens the internal carotid plexus left a groove on the lateral aspect of the
promontorium (see chapters 2 and 3). These taxa are thus considered to exhibit the “0”
state, “groove for at least promontorial branch present.” Only N. gidleyi (AMNH 17388)
appears to lack evidence of the internal carotid plexus. Optimization of this character
reveals that Plesiadapidae should be coded with the “0” state.
For cranial character 6, “Position of posterior carotid foramen,” Bloch and Silcox
(2006) and Bloch et al. (2007) coded Plesiadapidae with a “0” indicating that the foramen
had a “posteromedial position.” The same set of specimens mentioned for character 5
reveal that the posterior carotid foramen is directly adjacent to the stylomastoid foramen
when preserved, which is a criterion for considering the foramen to have a
“posterolateral” position. Furthermore, in other taxa with the posteromedial state, the
posterior carotid foramen is often medial to the medial edge of the promontorium. In the
plesiadapids studied in Chapter 2, the foramen is lateral to the medial edge of the
promontorium. In fact it is lateral to the entire promontorium. Therefore, this character is
re-coded as “1,” “posterolateral” for the Plesiadapidae.
For cranial character 16, “Flaring of nasals,” Bloch and Silcox (2006) and Bloch
et al. (2007) coded Plesiadapidae with a “1” indicating that the nasals “do not flare at
caudal extent and have a narrow contact with frontal.” Pr. gaoi (UALVP 46685), N.
intermedius (USNM 309902), P. anceps (YPM-PU 19642), and P. cookei (UM 87990),
however, have nasals that are proportionally much wider mediolaterally than those of P.
tricuspidens (MNHN CR 125) at their caudal end and even appear to flare slightly
compared to the mediolateral width of these bones at their rostrocaudal midpoint.
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