Skippy innards

["Ralph Chapman" <Chapman.Ralph@NMNH.SI.EDU>]

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 
Sinosauropteryx "protofeathers".

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