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Re: When carnivores kill other carnivores... (Morrison movie questions)

Cliff Green wrote-

Most of the Ph.D vert Paleontologists here in Utah are extremely up on
allosaurs, and are highly dubious of the Saurophaganax not being a species
of allosaurus. Paul Bybee believes, as do I, ( for what my opinion is
worth, ) that Sauro is just a big A. fragilis. I own a cast of a first digit
hand claw of what was originally called Epantarias ( sp ? ) It is enormous.
It's at least twice the size of the same claw from a 30 foot allosaur, and
three times the mass. They were definately T-rex sized. FYI, If anyone wants
to see a photo of the 1/35th scale one that I sculpted last year, email me
off list and I will send you a jpeg.

Regardless of whether Saurophaganax maximus is included in Allosaurus, it seems sufficiently distinct to be a separate species. Chure (2000) listed the following diagnostic characters- postorbital lacks rugosity; atlas lacks prezygapophysis for proatlas, does not roof over neural canal; some cervicals with nearly vertical postzygapophyses; horizontal lamina along base of each side of pectoral neural spines arising from spine base cranially, free caudally; pleurocoels well developed further posteriorly than Allosaurus; chevrons craniocaudally expanded distally; femur bowed laterally; no astragalar butress on anterodistal tibia; distomedial crest of tibia more strongly developed than Allosaurus; metatarsal IV less divergent distally than Allosaurus.
Notably, not all large Morrison allosaurids are Saurophaganax. For instance, the holotype of Epanterias amplexus and NMMNH P-26083 (Williamson and Chure, 1996) share characters with Allosaurus fragilis, not Saurophaganax.

Mike Keesey wrote-

IIRC (and I could be wrong), some analyses actually place _Sinraptor_
and _Yangchuanosaurus_ closer to carcharodontosaurids than
allosaurids, so I suppose they might be equally good ancestor

That's true. Holtz (2000), Holtz et al. (2004), and Novas et al. (2005) place allosaurids and carcharodontosaurids together. Allain (2002), Coria and Currie (2002), and Rauhut (2003) place sinraptorids and carcharodontosaurids together. However, Novas et al. (2005) and Allain (2002) place Acrocanthosaurus in Allosauridae, while Holtz (2000) places Neovenator in Allosauridae. Also, Coria and Currie place Acrocanthosaurus outside their sinraptorid+carcharodontosaurid clade. Only Holtz (2000), Holtz et al. (2004) and Rauhut (2003) examine Neovenator, which may be a critical taxon.

Mickey Mortimer