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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.
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
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: