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Re: New Ruben Paper

Not quite - the premise is that several adaptations of the avian hip and femur excursion allow the pelvic girdle and thigh musculature to help support the lower, lateral abdominal walls, which appears to provide resistance to collapse for the posterior abdominal air sacs in living birds. It's actually a neat finding, and not at all implausible. The problems don't hit until later in the discussion, at which point the authors make a number of poor assumptions, including (but not limited to): 1) lack of the modern-condition air sac expansion makes flight impossible; 2) lack of the modern-condition posterior air sac expansion means a flow-through lung was not present, and 3) the only way to support the posterior air sacs is with the pelvic condition seen in living neornithines.

I'd be curious to hear what the authors think of flight and respiration in pterosaurs.

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 4:19 PM, Mark Hallett wrote:


As we always say, "wait for the paper", but is Ruben's entire premise actually based (on the the implication as I understand it from the SCIENCE DAILY article) that birds have inflexible or only potentially flexible knee joints? This is incorrect. --Mark

--- On Tue, 6/9/09, Mike Taylor <mike@indexdata.com> wrote:

From: Mike Taylor <mike@indexdata.com>
Subject: New Ruben Paper
To: Danvarner@aol.com
Cc: dinosaur@usc.edu
Date: Tuesday, June 9, 2009, 9:18 AM
Danvarner@aol.com
writes:
http://www.sciencedaily.com/releases/2009/06/090609092055.htm


From the article: 

    "Frankly, there's a lot of museum
politics involved in
    this, a lot of careers committed to a
particular point
    of view even if new scientific evidence
raises
    questions," Ruben said.

*nods wisely*


_/|_ ___________________________________________________________________
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http://www.miketaylor.org.uk
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