Re: New Ruben Paper

[Mike Habib <habib@jhmi.edu>]

I may post some more thoughts on the paper (which I just read through  
quickly), if I have a chance later.  For now, though, I think it bears  
noting that if the presence of abdominal support and hindlimb position  
in derived birds (and lack of these traits in theropods) precludes a  
theropod origin for birds, then it also precludes an avian origin  
within any other group of tetrapods, since, as the authors themselves  
note in both the paper and press release, those characters are  
apomorphies of crown-group birds.   Examination of the paper reveals  
that the authors favor a model in which an avian flow-through lung  
appears *within* Aves, somewhere near the base of Ornithurae.  Now,  
perhaps I have missed something critical, but I do not understand why  
this is any better supported than a transition to an avian flow- 
through lung further down the phylogeny, especially given the recent  
work by individuals like O'Connor and Claessens that indicate likely  
correlates related to an avian-style breathing system.  Quick and  
Ruben do address those studies, but not in a way that I found  
satisfactory (for what my opinion is worth).

I find this particular phylogenetic placement of the flow-through lung  
origins especially odd in the paper, because the authors also suggest  
(in both the popular press and the manuscript) that the expansive  
abdominal air sacs are required for flight.  This is probably not the  
case, but given that Quick and Ruben think it *is* true, I would  
expect their subsequent hypotheses to be consistent with a model in  
which the modern bird-grade air sac system is absolutely essential for  
powered flight.  I actually have quite a few gripes with their  
conclusions on what is required for flight, but that can wait for  
another time.  I will say that they spend and awful lot of time  
talking about how pneumatized skeletons are lighter than apneumatic  
ones, which bothers me quite a bit given that it was shown as far back  
as 1979 (via Prange et al.) that pneumatized skeletons are not lighter  
in total mass.  Granted, it still comes down to strength:weight  
ratios, so it's not completely off, but the semantics are inaccurate  
enough that they should have been caught in peer review.

I admit that I do not particular feel good about talking down a paper  
whose lead author is a fellow young researcher that just finished her  
PhD.  Devon does have some very good work here, and I hope that the  
recently minted Dr. Quick continues to work on avian respiration and  
physiology, because there is some very useful stuff in the paper.   
Several of the conclusions, though, just aren't up to snuff, and I  
simply do not see any way around that.

Cheers,

--Mike


Michael Habib, M.S.
PhD. Candidate
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
(443) 280-0181
habib@jhmi.edu



On Jun 9, 2009, at 12:35 PM, John Conway wrote:

> Reading that, I was wondering how this stuff gets past peer review...
>
> Well, the answer is that it doesn't. At least not in this case, from  
> what I can see.
>
> It's a dishonest tactic to imply in press releases and interviews  
> that your (peer reviewed) paper supports a conclusion which it  
> doesn't--especially because we know full well that most people won't  
> read the paper.
>
> This kind of stunt is really damaging to science.
>
> The paper is open access:
> http://www3.interscience.wiley.com/journal/122395783/abstract
>
>
> Danvarner@aol.com wrote:
> > http://www.sciencedaily.com/releases/2009/06/090609092055.htm
>
> --
> Palaeontography: http://palaeo.jconway.co.uk