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To all list people:

   I have stayed pretty much in the background, contacting individuals
when it seemed relevant and relying on Tom Holtz's comments to cover
most of what needs to be said here. He generally is right on the money
and reasonable in his tone. I'm a morphometrican/paleontologist here at
the National Museum of Natural History (Smithsonian Institution) and
work on dinosaurs at times as well as lots of other things.

  I just wanted to comment on the tone of PJANKE's comments that greatly
disturbs me. The discussion on whether an impact of some sort happened
at the K-T boundary is an ongoing scientific discussion that includes
lots of people and lots of conflicting evidence. I personally believe
an impact happened there and have been swayed by much of the evidence,
although there are problems and possibilities that surround all the data
that are coming out. However, it is far from totally settled, despite
what PJANKE states. Was there probably an impact then - I think so.
Did it knock off the dinosaurs (minus birds), WE DON'T KNOW. The
correlation of the timing of events documented in the marine sediments
and those in terrestrial sediments is incredibly difficult, especially
in timing extinction events where you have various sampling problems
including the Signor-Lipps effect, etc. If you were to poll most
dinosaur workers I suspect they would still tend to suggest the extinction
of non-avian dinosaurs was still gradual rather than abrupt, taking
all of these factors into consideration. This was done at Drumheller for
the Dinosaur Systematic Conference (ending in the Carpenter-Currie volume)
and this was the result and I suspect it still would be. If there was
a gradual decline in dinosaurs at the end of Cretaceous from many taxa
to few and a few hangers-on were knocked off by an impact, that does not
make the impact the main explanation for the decline of the non-avian dinosaurs
The gradual decline must be addressed. If you look at other groups that
go extinct at various times, some go quick and from many to 0, and others
hang on with their fingernails and give out last gasps around the times of
major extinctions. In the latter case, the major extinction does not
account for why the taxon lost out, it was just the final nail in the coffin.
The interesting questions are in figuring out why the taxon ran out of gas.
   So, back to the K-T discussions. Nothing is fully settled and there is
no reason for this flaming condescension that seems to get so developed
in some of the notes. Some of the comments on this topic, and also in
the discussions of SUE, have entered the realm of religion and are
non-scientific in their nature. Stop it and relax. The dinosaurs aren't
going anywhere and we can be patient as the various players continue to
present and refute evidence here. Will it come out that dinosaurs were
declining at the end of the Cretaceous and there are interesting areas
to research here? I think so. Will it come out that there were still a number
of non-avian dinosaurs running around that, when confronted by an impact,
more or less said the hell with it and kicked off, effectively ending the
time of the non-avian dinosaurs? I think so too. Will there be fossils
(articulated, good ones) of post-Cretaceous non-avian dinosaurs
found somewhere? Probably, but dinos would still be very very rare then
and that would not argue against the importance of the impact, if it
did occur, or the end-Cretaceous drop in dino diversity, if it did
occur. I don't know why Alroy was so strong in his arguments for the impact
because the data still need to stand up to more scrutiny. I say this even
though my opinion and evaluation of the evidence is probably very similar
to his. I just know how quickly evidence can become non-tenable at this
stage in the investigation of events like extinction events.
   So, what I've long-winded here is to suggest that if you cannot
introduce your arguments and data in a civil manner, than you should
think twice about stating them at all. This is a wonderful and complex
issue that should be discussed here, and netters should feel free to
introduce evidence to support any view they have. Just remember it's
a difficult and complex issue with lots of statements being made in
the press to make an impact and freqently even the researchers are
going beyond the evidence they had. The Alvarez research was over-stated
for years before evidence accumulated to back up most of what they were
saying, despite the strong rhetoric that they used in the early days.
Peter Dodson has been cautious for good reason, he knows the dinosaur
evidence that 99% of all those making statements about the extinction
of the dinosaurs do not know. I think paleontologists have a responsibility
to expect all connections and problems to be addressed before they
make wild statements to the public. I think some dinosaur types would do
well to learn from this. The pro-impact people (and I'm probably one at this
stage) have a ways to go to finalize an impact at the K-T boundary. this
is only the start, however, becasue then they have to tie it into
the patterns we see for dinosaur diversity. This will be tough but a
wonderful excuse to keep looking at dinosaurs (as if we need some)

   So, hopefully this wasn't too convoluted. I hope the list can get
into other topics such as sexual dimorphism (a pet of mine since I
described the best example of such in the Dinosauria in Stegoceras
with Bill Wall, Jack Sepkoski and Peter Galton in 1981). I'm
amazed at all this talk about morphs in T rex without much supporting
published evidence that is at all persuasive.

Ralph E. Chapman, Applied Morphometrics Laboratory
National Museum of Natural History, Smithsonian Institution
Washington DC USA:  MNHAD002@SIVM.SI.EDU