UNQUILLOSAURUS IS AVIALIAN?

["Darren Naish" <dwn194@soton.ac.uk>]

I was very intrigued with Tracy's suggestion that _Unquillosaurus_ might be
something to do with _Unenlagia_. But known as it is just from a weird pubis,
I can't really see the case (unless I've misinterpreted what Tracy wrote, in
which case I apologise).

The _Unquillosaurus_ pubis has a slight posteroventrally directed foot, its
shaft seems to have been just about straight and it has this really strange
little notch on the lateral (I think) face just beneath the articulation with
the ilium. This doesn't agree much with _Unenlagia_ where the pubis is this
remarkable J-shape (the hook of the J is directed posteriorly of course) - a
fantastic design that is _not_ unique amongst Dinosauria (eh Pete?;-)).

I found an old drawing in my copy of Weish-Dod-Os where, based on Powell's
(1979) figure, one of my colleagues had attempted to mirror the pubis so as to
reconstruct the pair. Looking at this now, the symphasis is not long and
restricted to the distal third or so. I suppose it looks a bit like the
_Unenlagia_ pubes as figured in cranial view by Puerta and Novas, but then some
other theropods have pubic symphases restricted to the distal third. Can't say
I've looked at enough theropod pubic aprons or symphases in cranial view to
know, though..

_Unquillosaurus_ is from the Los Blanquitos Formation in Argentina - this is
given as ?Campanian by Norman. _Unenlagia_ was Camp-Maastrichtian wasn't it, so
perhaps these animals were roughly contemporaneous. I've always assumed (based
I guess on the silhouette in David Lambert's _Collins Guide to Dinosaurs_!)
that _Unquillosaurus_ was a big beastie, but, silly me, I forgot to check the
size of the pubis. Anyone know off hand?

"Organization is the enemy of improvisation"
Thank god.

DARREN NAISH