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Re: New Ruben Paper

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.



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:

Danvarner@aol.com wrote:

-- Palaeontography: http://palaeo.jconway.co.uk