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Re: The Enigma of Psittacosaurus

----- Original Message -----
From: "Steve Brusatte" <dinoland@lycos.com>
To: <dinosaur@usc.edu>
Sent: Monday, July 08, 2002 11:30 PM
Subject: The Enigma of Psittacosaurus

> >8. laterally projecting jugal horn.
> A good character that has been recognized since Sereno's paper in _The
Dinosauria_.  The polarity is known, >which makes it valuable in deducing
psittacosaurid relationships.

I think that the usage of laterally projecting jugal horn is a generalized
character for Psittacosaurus species, infact within Psittacosaurus the jugal
horn is highly varibale, in most species the jugal horns point backward with
the skull in dorsal view, nevertheless P. sinensis and P. xinjiangensis have
jugal horn that point almost forward and the rostral edge is nearly
perpendicular to the skull mid-line. P. meileyingensis has small jugal horn,
while P. neimongoliensis and P. youngi have larger jugal horn directed
backward. P. ordosensis has fairly large jugal horns also directed backward,
P. mongoliensis has long jugal horns directed laterally.

Alessandro Marisa
Via Achille Grandi n°18
Rovereto (TN) ITALY
Tel: 039-0464-434658 Email: amaris@tin.it