[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
RE: PTEROSAURS: AVIAN ANCESTORS?
-----Original Message-----
From: Jeffrey Martz [SMTP:martz@holly.ColoState.EDU]
Sent: Monday, September 28, 1998 11:50 AM
To: Matthew Troutman
Cc: dinosaur@usc.edu; larryf@capital.net
Subject: Re: PTEROSAURS: AVIAN ANCESTORS?
A couple of these topics will be addressed at SVP...
> Larry Martin views these animals as crocodylomorphs based on
several
> features. However, the majority of people think that _Cosesaurus_
and
> _Megalancosaurus_ are prolacertiforms. Dave Peters views
_Cosesaurus_
> as the sister-group to pterosaurs.
>4) There is really no "time problem in the theropodian=>bird
hypothesis.
Early maniraptorians are springing up all over.
John Ruben will be giving a talk at SVP backing up the
assignment of
Megalancosaurus as a bird predecessor. Chris Brochu will be giving
a talk
on the "time problem" (or lack thereof), and, and there will also be
a
talk describing a possible way around the embryological problem bird
digits. No one has yet explained to my satisfaction why the "time
problem" between Megalancosaurus and Archaeopteryx is less
significant
then the one going in the opposite direction between really
bird-like
theropods and Archaeopteryx.
Larry Dunn mentioned the scientist who claims that "naughty
mice
could trip T.rex" if it ran. If you've read Farlow's paper, I think
it is
pretty clear that the "tripping mouse" drawing was a joke. Farlow's
point
was "if a multi-ton animal falls down, its going to hurt itself, so
maybe
being a huge bipedal runner was kind of dangerous". Continued
resistance
to this pretty unpretentious suggestion presumably continues because
it makes T.rex look like a wuss.
I've thought a lot about this one & frankly wonder how an NFL
lineman ever recovers from a high speed collision??? :-) Large animals,
LIKE NFL lineman are inclined to be pretty darn sturdy. And if
Tyrannosaurus Rex was as muscular as it now SEEMS he or she was, then
falling down, even while running at it's top speed should not prove too
catastrophic. Yes, T. rex was much taller AND longer than MOST NFL linemen,
but wouldn't a lot of that massive body be hard muscle?
Muscle is a terrific shock absorber. Also, Tyrannosaurus rex (as it
is envisioned now) looks pretty well balanced to my 49 year old physicist's
eyes. :-) I suspect he/she would be mighty doggone difficult to trip up!
Elephants & rhinos take some pretty nasty spills & (usually) shrug it off.
Dwight
I think most of the resistance to Scott Hartman's claim
regarding
feathers on _Velociraptor_ results mostly from his questionable use
of
"almost certainly". Apparently unfeathered skin impressions in at
elast
some theropods make the exact distribution of integument among
theropods
pretty ambiguous.
LN Jeff
(Not saying much of importance these days.)