Re: Pygostyle

["Jaime A. Headden" <qilongia@yahoo.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? If he does (being
a basal deinonychosaur himself), then it may indeed be
an ancestral pygostyle. On the other hand, if he
doesn't, then the stiffened tail was only a later
adaptation within the Deinonychosauria and cannot be a
primitive pygostyle.>

  Given that *Sino* does have the feature (not the
pygostyle) this doesn't neccesarily mean anything
besides the early development of the stiff tail
balancing feature in the group, that
"hypsilophodontians" and pachycephalosaurs also
possess. Go fig.

<(Assuming, of course, that Deinonychosauria is
monophyletic, which I don't think anyone disputes.) 
So does he?>

  What version of Deinonychosauria? Sensu Gautier?
Sensu Padian et al.? Do you include Troodontidae in
this, or not? The inclusion of specific taxa is the
dispute, and as the Ostrom Symposium demonstrated,
there's evidence they are closer to each other than
either is to other taxa, from independant studies.
Check out the posts on "Ostrom" in the archives for
further details, but I think Norell and Martin were
the two main (or only) presenters of this phylogeny.

<Also, do _Archaeopteryx_, _Rahonavis_ and _Unenlagia_
have such a tail as well?  (I don't think so, but...)>

  *Archeopteryx* and *Rahonavis* do have stiffened
tails formed by elongate centra and chevrons, more so
in *Rahonavis* and dromies than in Archie, while the
only specimen of *Unenlagia* lacks caudal material
(same if *Megaraptor* is referrable to Unen).

  Speaking of Unen, what is the correct
pronounciation? Following Spanish rules, it's
yoo-nyen-LAG-ee-yah; following Latin, it's
oon-EHN-lahg-yah or oo-nehn-LAHG-ee-yah. Ben, you got
a handle on the Mapuche rules on this, or what?

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