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Re: Bahariyasaurus ingens



Todd Marshall wrote-
 
I was wandering if any of you kind souls could please help me out? I'm getting ready to work on an illustration for a client, of Bahariyasaurus ingens. I'm aware that the specimen type was destroyed in WW II, a femur, fibula and some postcranial elements if I'm not mistaken. I was reading in Gregory S. Paul's book PDW, that this therapod was put into the megalosaur group, but there were aspects of the bones gracility that make it very tyrannosaur-like. Has there been any new fossils or evidence on this animal unearthed? Any information on this animal would be greatly appreciated. Any size and length estimations to reconstruct this animal would also help a lot.
 
First of all, the remains of Bahariasaurus are not nearly complete enough for a restoration in my opinion.  Information on the holotype-
holotype- (IPHG 1922 X47) dorsal vertebra (200 mm), dorsal vertebra (~180 mm), neural arch, rib fragment, sacral vertebra (~135 mm), sacral vertebra (~120 mm), sacral vertebra (~120 mm), pubes (1.03 m), proximal ischium
If we compare the pubic length to that of Allosaurus, we get a length of 11 meters and a mass of 3.5 tons.
The specimen including the femur and fibula (IPHG 1912 VIII) was referred to Deltadromeus by Sereno (1996).  Bahariasaurus differs from Deltadromeus in- broader pubic shaft; pubic foot divided in the midline; iliac peduncle of ischium narrower.  However, I have heard from good sources that the supposed pubis of Deltadromeus is really an ischium, rendering the first two characters moot.  Is the narrower iliac peduncle reason enough to keep these two genera separate?  So on the one hand, you have a situation where Bahariasaurus could be synonymous with Deltadromeus, which is non-tyrannoraptoran, and possibly non-coelurosaurian.
Rauhut (1995) did a study on Carcharodontosaurus and Bahariasaurus where he considered the latter a member of the Carcharodontosauridae within the Allosauroidea.  This was before the description of Deltadromeus, so he included IPHG 1912 VIII in Bahariasaurus.  I unfortunately lack this paper, but the summary in Glut's encyclopedia indicates at least some proposed carcharodontosaurid synapomorphies are determinable in the holotype (pubic symphysis reduced proximally and distally; pubis bowed anteriorly; obturator process offset from pubic peduncle).  Whether these are actually characteristic of Bahariasaurus and Carcharodontosaurus (and perhaps Giganotosaurus and Acrocanthosaurus) would require an analysis beyond the scope of this post.  Thus we have a second possibility for Bahariasaurus- that it's a carcharodontosaurid carnosaur.
I can't recommend one possibility over the other at the moment, but you can see why I don't think a reconstruction is a good idea at this point.
 
Mickey Mortimer