Boyer diss 2009 1046..

petrosal bulla predicts that a suture delimiting the presence of two different bones was
present at some point during the ontogeny of a given individual. If the bulla was not
petrosally derived then it is possible that sutures, or some remnant of a mostly obliterated
suture between the petrosal and the bulla, will eventually be preserved.
The position of the posterior carotid foramen, presence of an intratympanic route
for the internal carotid plexus, and the presence of the foramen rotundum are addressed
by assessment of morphology in new and existing specimens described here. The
controversial suggestion that plesiadapids had a petrosal bulla (Russell, 1964; Gingerich,
1976; Bloch and Silcox, 2006) is addressed with these new fossils, new comparative data,
and use of advanced visualization techniques such as high resolution x-ray computed
tomography (HRxCT) and scanning electron microscopy (SEM). Specifically, I present
new detailed photographic, HRxCT, and SEM data on the medial tympanic processes of
new and existing plesiadapid specimens, various rodents (marmots – Marmota,
chinchillas – Lagostomus, and kangaroo rats - Dipodomys), other plesiadapiforms
(paromomyids) and euprimates (Indri). These data allow a more detailed assessment of
the morphological evidence for bullar composition than was possible previously.
Anatomical terminology
The anatomical terminology employed in this study follows that of MacPhee
(1981) with respect to anatomy of the tympanic region (i.e., structures of and surrounding
the petrosal). Generally speaking, Miller’s Anatomy of the Dog (Evans, 1993), Nomina
Anatomica Veterinaria (1994) and Nomina Anatomica (1983) are followed with respect
to the rest of the cranium. Wible and Gaudin (2004) and Wible (2008) provide glossaries
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