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Re: tyrannosaurid ancestry, raptors and other fun things...
Michael Keesey wrote-
>Seeing as all the non-tyrannosaurid tyrannosauroids are ambiguous, that
>would have to be _Alectrosaurus_, from the Turonian(?).
Not true. Aublysodontines/shanshanosaurines are considered to be true
tyrannosaurids and have been reported from earlier sediments. Undescribed
aublysodontine material (teeth, I suspect) has been reported from the early
Cenomanian of the upper Cedar Mountain Formation and from the middle-late
Cenomanian of the Dakota Formation, both in Utah, by Kirkland et al. (1998).
Gangloff (1998) also refers a tooth from the Chandler Formation (Cenomanian)
of Alaska to Alectrosaurus, which is certainly a tyrannosaurid (Mader and
Bradley 1989) and was referred to the Aublysodontinae by Currie and Eberth
(1993). A tooth from the Kitadani Formation of the Akaiwa Subgroup of the
Tetori Group (Aptian) (I think I have that straight) in Japan is D-shaped
with serrations, which is only known in tyrannosaurine premaxillary teeth.
I don't think it's been described yet, but it was discussed on the list a
while back. Kirkland et al. (1998) also reported tyrannosaurine remains
from the Dakota Formation. Finally, Zinke (1998) described sixteen teeth
from Guimarota in Portugal (early Kimmeridgian) that probably came from an
aublysodontine. Also, what makes Siamotyrannus' (Berriasian-Barremian)
referral to the Tyrannosauroidea ambiguous? It seems to share quite a few
synapomorphies with tyrannosaurids.