Re: Pygostyle-like structure from Beipiaosaurus

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
Sent: Monday, October 13, 2003 3:31 PM

> Also, although I haven't seen Beipiaosaurus' pygostylar structure, that of
> Nomingia is by no means as extensive as those of pygostylian birds,

However, those of *B.* and *N.* are apparently equally extensive -- 5 fused
vertebrae. In *B.*, the 2 preceding vertebrae are also fused to each other.
The
sutures are less visible than in *N.*. And based on the apparently separate
last sacral, the specimen may be immature, so perhaps the pygostyle would
still have grown. *Caudipteryx* is mentioned as lacking a pygostyle.

The long, oblique prezygapophyses look like in *N.*, and the ilium looks
like in *Alxasaurus*. It's interesting that there are at least 30 vertebrae
in the tail.

I don't know if the preparation is good enough to tell if there were
rectrices. According to the text, the preservation may be too bad anyway.