THE UNIVERSITY OF CALGARY Eric Snively A ... - Ohio University

Troodon, with the most gracile metatarsal proximally, has the highest eigenvalue
for PC2 at 0.607. Elmisaurus has the lowest PC2 value among proximally gracile
forms, at 0.13. Because Elmisaurus is a member of the oviraptorosaur clade, its
position relative to others in that group is noted below.
2. Oviraptorosauria (Oviraptoridae (Ingenia, Rinchenia) + Elmisauridae
(Elmisaurus)), Therizinosauridae (Segnosaums), Dromaeosauridae
(ûeinonychus), and Ornitholestes (Figure 2.1 7). These coelurosaurs show a
great diversity in MT III shape. Elmisaurus, which is qualitatively considered
arctometatarsalian (Holtz 1994a, b), shows the highest value for PC2 among
oviraptorosaurs. The oviraptorid Ingenia shows high variability (PC2 values of
-22 and -û.06), while Rinchenia mongoliensis is intermediate between lngenia
and Elmisaurus. The dromaeosaurid Deinonychus and Omifholestes are
undifferentiable from the oviraptorosaur cluster.
In contrast, the therizinosaurid Segnosaurus is set apart from its
oviraptorosaur sister group in both size (PC1) and shape (PC 2). Its PC1 value is
fairly high at 0.61, and its PC2 value is the lowest of any of the examined
theropods, at 4-39.
3. Carnosauria (Figure 2.18). Carnosaurs, al1 of which are relatively large, cluster
strongly along PC1. They show more variation in shape than the similariy large
tyrannosaurids, however, and are spread out further along PC2. The carnosaur
MT III appears to become more gracile proximally with increasing linear size; the
highest PC2 values occur for the large Allosautus (Saurophaganax) maximus