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Re: Bahariasaurus & other questions
"Dino Rampage" wrote-
1) What is Bahariasaurus ingens? Is it a carnosaur closely related to the
carcharodontosaurines (as was traditionally assumed) a basal tetanuran with
unknown affinities, or is it possibly a basal coelurosaur similar to
PAUL 1988 placed it as the closest allosaurid to the Tyrannosauridae, but I
think that much of that was based on material now referred to Deltadromeus.
SERENO et al 1996 do not consider a placement for this taxon but refer the
material to D. Mikko Haramo (CMIIW in spelling) placed it as a basal
coelurosaur on his website. Rauhut wrote in his PhD thesis that B. lacks
any characters linking it the Carcharodontosauridae and that it is very
close to Deltadromeus. CARRANO 2002 considers Deltadromeus to be a
KURZANOV 1989 also placed it and Carcharodontosaurus saharicus as the
closest allosaurids to the Tyrannosauridae, but he does not cite PAUL 1988,
and he uses the following characters to determine their placement-
-Superior temporal fenestra merge above the temporals
I don't really understand this character as when I look at the skull of
tyrannosaurids in dorsal view, they do not appear to merge, but they are
very close together. Perhaps the translator made an error.
-Amphicoelous anterior dorsal vertebrae
Also in ceratosaurs, Szechuanosaurus? zigongensis, and nearly all
coelurosaurs (incl. tyrannosaurids).
-Centrally located neural processes in the caudal vertebrae
I presume he's talking about the neural arches, but aren't these always
-Acromial region of the scapula extremely wide
Evidentally, the scapula (HM 1912 VIII 60) was referred away from B., so
this character cannot be used. I presume it was referred to Deltadromeus,
because the figures in SERENO et al 1996 illustrate D. with this character.
-Triangular obturator process
This is supposed to be present in at least maniraptorans. It's not present
in Sinosauropteryx or the Santana compsognathid (SMNK 2349 PAL).
He also considers Acrocanthosaurus atokensis to be a close relative to the
Tyrannosauridae based on the following characters-
Could someone clarify on this character?
-Wide postorbital edge
-Mature pleurocoels on the posterior dorsal vertebrae
Dorsal pleurocoels are present in at least Yanornis, Changchengornis,
Confuciusornis, Deinonychus, Eoalulavis, Hesperornis, Ichthyornis,
Longchengornis, Neuqueornis, Nomingia, Oviraptorids, Protopteryx, Rahonavis,
Saurornitholestes, Cathayornis, the Spanish nestling, Nanshiungosaurus?
brevispinus, Beipiaosaurus, Microvenator, tyrannosaurids, Caudipteryx, and
possibly Archaeopteryx. They should be present in more taxa, but I'm not
BAKKER et al 1988 also consider A. atokensis to be a close relative to the
Tyrannosauridae (and ornithomimids, troodontids, birds, and oviraptorids but
not dromaeosaurids[!]) based on the following characters-
-paroccipital process very deep top-to-bottom at the root
-large excavation around the fenestra ovalis
-pneumatization of the paroccipital root
Are the latter two even present in tyrannosaurids or Acrocanthosaurus?
I also recommend looking at these-
That's all I know. Others will be able to provide more complete information
and probably can correct some stuff in this post and answer some of my
questions too. That's the beauty of the Dinosaur Mailing List. :D
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