Re: Pygostyle

["Ralph W. Miller III" <gbabcock@best.com>]

> Grant Harding wrote:
>
> <I heard mention somewhere that someone once suggested
> (references please?) that the stiffened tail of
> dromaeosaurids was an early stage in the evolution of
> the pygostyle.  As a result, I have a question: does
> _Sinornithosaurus_ have such a tail?

Apparently it does.  While most of the tail is missing, there are the
following (quoting the caption to Figure 2):

spine of caudal vertebra
elongated prezygapophyses and chevrons of mid- and posterior caudal
vertebrae

These elements rest adjacent to one of the hands.  They are easiest to
see in Figure 4, "_S. Millenii_, selected elements of the postcranial
skeleton."

The tail was stiffened by the elongate prezygapophyses, as in other
known dromaeosaurid dinosaurs.

-- Ralph W. Miller III       gbabcock@best.com