Re: Allosauroid cladogram

["Alessandro Marisa" <iguanodontia@yahoo.it>]

----- Original Message -----
From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
To: <muaddib7@unm.edu>; <dinosaur@usc.edu>
Sent: Friday, July 11, 2003 2:00 PM
Subject: RE: Allosauroid cladogram

> My 2000 paper had fewer taxa, and had the form Monolophosaurus +
((Sinraptor
> + Yangchuanosaurus) + ((Allosaurus + Neovenator) + (Acrocanthosaurus +
> (Giganotosaurus + Carcharodontosaurus)))).
> Sereno et al.'s 1996 phylogeny similarly had a polytomy: Sinraptoridae,
> Cryolophosaurus, Monolophosaurus, Allosaurus, and Giganotosaurus +
> (Acrocanthosaurus + Carcharodontosaurus).

Using their previous analysis (Currie e Carpenter 2000) Coria and Currie
(2002) in describing the Giganotosaurus's braincase performing a new
analysis adding 15 new braincase's characters and obtain an interesting
result: Sinraptor, Carcharodontosaurus, and Giganotosaurus form a
monophyletic group in which Sinraptor is the sister taxon to a
Carcharodontosaurus+Giganotosaurus clade.
The Sinraptor_Carcharodontosaurus_Giganotosaurus group is supported by five
(unequivocal) synapomorphy and one (equivocal): (1) strong posteroventral
orientation of the braincase in relation to the frontal region of skull
roof; (2) vertical longitudinal axis of temporal fossa inclined at an angle
of more than 120°; (3) supratemporal fenestrae open more anteriorly than
dorsally; (4) parallel postorbital articulation and parietal margin; (5)
supraoccipital knob at least twice the width of foramen magnum.
Unfortunately for the fun (I'm one) of a Carcharodontosaurids affinities of
Acrocanthosaurus, Coria and Currie stated that the braincase of
Acrocanthosaurus lacks all of the Carcharodontosaurids braincase
synapomorphy, suggesting that it is not related to this group.

By
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Alessandro Marisa
Via Achille Grandi n°18
38068 Rovereto (TN) ITALY
Email: iguanodontia@yahoo.it
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