Re: Broader than Dinosauria

["Alessandro Marisa" <amaris@tin.it>]

----- Original Message -----
From: "Jaime A. Headden" <qilongia@yahoo.com>
To: <dinosaur@usc.edu>
Cc: <kinman@hotmail.com>
Sent: Sunday, September 09, 2001 8:20 AM
Subject: Re: Broader than Dinosauria


>   In *Lagerpeton*, the acetabulum is completely closed.
>   In *Marasuchus* and *Lewisuchus* and, I believe, *Psuedolagosuchus*,
there is a triangular apse
> between ischium and pubis, with a level ventral margin of the
intra-acetabular portion of the
> ilium. This is a "partially open acetabulum" as not all elements appear to
be "regressing" from
> the apse.

I want to remember that in his paper on SVP 16 (4) 1996 Dr. Novas argued
that the presence of a perforate acetabulum in Marasuchus is equivocal, the
problem merges from an erroneous reconstruction of the acetabulum based on
PVL 3870 in which the ilium forms a triangular ventral projection, as in
others Archosaurs with imperforate acetabulum (es. Saurosuchus, and
Gracilisuchus). The ischium and pubis do not contact the ilium because the
acetabular extremity was broken, resulting in an artefact semicircular gap,
erroneously interpreted as an acetabular perforation. In the right pelvis of
PVL 3871 the acetabular portion of both pubes and ischium is completely
preserved and lacks the semicircular gap of PVL 3870, Novas concluded that
the combined information of pelvis morphology of PVL 3870 and 3871 suggests
that Marasuchus has an imperforate acetabulum.

By
____________________________________________
Marisa Alessandro
"Volounteer of Museo Paleontologico Cittadino, Monfalcone"
Via Achille Grandi n°18
38068 ROVERETO (TN) ITALY
Tel:039-0464-434658 Email amaris@tin.it
Museum Web-Page: http://www.fante.speleo.it
____________________________________________