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Well, that was some article in the NY Times on skippy innards. Brought to mind
the following thoughts. I haven't seen the Science paper yet but will go by the
article as given on the list and past talks.
1) Crocs are the only near (or semi-near) basal archosaurs we know much about
so I'm not at all sure what type of respiratory system the Oregon group thinks
that bird respiration actually evolved from. Maybe they don't think they are
archosaurs anymore. I'm also ALWAYS bothered when I hear a scientist pronounce
that something could not have evolved from something else, especially when they
have no real evidence for an alternative. They can imply that birds popped (not
pooped) out of the archosaurs before the croc-like system developed but they
can only make this point, again, with a solid phylogenetic analysis that
demonstrates this and, frankly, I have yet to hear anything even near
persuasive from them that really shows what they say is there. I hope their
paper does a much better job of this than their SVP discussions. I suspect they
are seeing what they want as much or more than dino-origin types are doing with
2. I'm sure glad Larry Martin didn't try and overstate their case for them
(sarcasm here for those who can't tell). His suggestion that dino-origin types
have their opinions set to stone and ignore evidence on this issue is a tad
ironic given some of the near desperate comments I've heard from him and
Feduccia during this debate. Yes, it's far from over but these data far from
tilt things much or at all. I get very tired of hyperbole that seems to become
mandatory these days. Yes it's a nice specimen that's exciting. It's also a
juvenile which complicates things to some degree and there is a tremndous
amount of interpretation going on. Larry is doing a good service these days by
making an effort with phylogenetic stuff and requiring rigor from those doing
phylogenetic work attempting to show dino origins. However, it is now time to
require equal rigor on those arguing against it - or at least some rigor.
3. They may be correct on their interpetation of the croc system but, as I said
above, they cannot just state that x can't evolve from y. Just as models of the
origin of flight that state it must have originated in some way and could not
of in another don't work well either. These are called "just so stories" in the
business and can be fun, but are not particular useful in scientific
discussions that are trying to be quantitative and robust. In the
pre-Continental drift days the opposition said it couldn't have happened
because there is no mechanism. This despite a huge amount of evidence that it
had to. Well, eventually mechanisms were found and the main story to get from
this is "What has happened, can happen".
So, I don't know where birds come from yet. I don;t really care one way or
another, but I'd like to know. The evidence is still overwhelming that a dino
origin best fits the data but there is plenty of room for that to be wrong.
However, it will take lots of evidence, lots of quantitative data, lots of
robust analytical thinking, and lots of new material - and fewer just so
stories from all sides - before we can have total confidence.
This should make for a very interesting meeting in New Haven.
I'll also buy a beer (or diet Coke for me) for anyone that can find a Middle
Jurassic, or thereabouts, lagerstatten from a lake or coastal area that has
verts in it. Obviously that's where the action is (maybe early Upper, or even
late Early). Just gotta find some more rocks. Not asking for much, am I?
Less Hyperbole and More Rigor.
"Deeds not Words"
Ralph Chapman, NMNH
Ralph Chapman, NMNH