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otundum appears to be formed between the alisphenoid and orbitosphenoid. These facts<br />

suggest the previously identified foramen rotundum is actually a sphenorbital fissure.<br />

Therefore, I changed the coding for P. tricuspidens to the “0” state (absent). This allows<br />

Plesiadapidae to also be represented by a “0.”<br />

For, cranial character 23, “Shielding of cochlear fenestra,” Bloch and Silcox<br />

(2006) and Bloch et al. (2007) coded Plesiadapidae and Paromomyidae as “2,” indicating<br />

that the fenestra is “shielded by a bony septum.” Adapid euprimates, on the other hand<br />

were coded by them with a “1,” indicating that the fenestra is “shielded by an arterial<br />

tube.” The bony shield referred to in cranial character 23 is the “posterior septum” of<br />

MacPhee (1981). As discussed for plesiadapids and and paromomyids in Chapter 2, a<br />

bony tube for the internal carotid plexus runs through the base of the posterior septum.<br />

This can be observed directly in P. tricuspidens (MNHN CR 125 and the Pellouin skull),<br />

Pr. gaoi (UALVP 46685, UALVP 46687, UALVP 49105) and I. graybullianus (e.g.,<br />

USNM 482353, USNM 421608). I cannot see how this differs from the state assigned to<br />

Adapidae, for instance. Therefore I changed the coding from “2” to “1” for both<br />

plesiadapids and paromomyids.<br />

For cranial character 24, “Auditory tube that runs through lateral wall of anterior<br />

chamber,” Bloch and Silcox (2006) coded carpolestids as having the “present” state.<br />

Study of the original specimen of Carpolestes simpsoni UM 101963 and discussion with<br />

J. Bloch lead me to conclude that the bone separating the carpolestid bulla into an<br />

anterior and posterior chamber (the “platform bone” of Bloch and Silcox 2006), is in fact<br />

a piece of the ectotympanic bone that has been pushed out of place. Therefore, the<br />

515

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