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Assuming that segnosaurs do belong in the theropoda, what is thier
exact position? Given the scatter of bullatosaur, oviratosaur, and
dromeosaur characters, there has got to be a lot on convergence going on.
As near as I can see, the only thing really tying them to dromeosaurs is
the opisthopubic pelvis. Most features suggested by Clark et. all,
and Russel & Dong seem to suggest ties with oviraptosaurs and
bullatosaurs, especially ornithomimids.
1) primitive metatarsel (non-arctometatarsalian)
2) basipterygoid process redued or absent, fused to pterygoids
3) broad quadrate ramus
4) vomers extend to basicranium
5) Palantine fenestra
6) Ulnar facet of humerus expanded, merges with entepicondyle (alo in
7) expanded preacetebaular area of illium
8) enlarged medial tuber on clacaneum.
1) big pneumatic basisphenoid (also in oviraptids?)
2) troodont-like teeth, and troodont-like depression in otic region
3) Supratemporal fossa does not extend forward (ornithomimids)
4) small teeth (ornithomimids)
5) dentary teeth more numerous then maxilla (troodontids)
6) Capitular facet situated above lamina on prezygapophyseal base
7) cotylus for ibula on tibia small and medially situated
Oviraptosaurs AND ornithomimids:
1) edentulous premaxilla
2) broad, rounded premaxilla with large palatal shelf
3) secondary palate over vomers formed by maxilla and premaxilla
4) coronoid absent
Again, a litle discussion would help clear things for me, and I'm sure
certain people would be happy to reopen this particular can of worms.