[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Allosauroid cladogram

----- 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 +
> + 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.

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