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Re: The ACTUAL flying Microraptor paper in PNAS
I finally read the paper.
Right below the author addresses, it says "Edited by Alan Feduccia". The
bottom right corner of the first page says "This article is a PNAS
Direct Submission. A. F. is a guest editor invited by the Editorial
Board." Now, "direct submission" means it was peer-reviewed (judging
from the instructions to authors:
http://www.pnas.org/site/misc/iforc.shtml), but, while the
acknowledgments list a lot of people, nobody is mentioned to have
reviewed the manuscript...
As the abstract describes, the decision between the flat pose and the
biplane one (legs vertical and crouched, metatarsal feathers sticking
out sideways, which would explain why they're so extremely asymmetrical)
was made based on which one makes a better glider. This presupposes that
*Microraptor* was a glider, _and_ that it was anatomically able to
assume both positions.
The abstract and the supp. inf. (1st page) say that sprawling up to ~
70° from vertical was possible -- but this assertion isn't tested
anywhere in the paper or the supplementary information. The authors
merely mention that they looked at "several hundred specimens" and ">100
additional specimens" (p. 2972) or ">300 microraptorians" and "hundreds
of other deinonychosaurians with plumage and feathered feet along with
thousands of Chinese Mesozoic birds" (1st page of supp. inf.), but don't
provide any illustration, any description of what the hip joint looks
like, any mention of diagenesis, anything -- only two specimen numbers
are given in the supp. inf., but those specimens were used for
reconstructing the shape of the plumage; the hip joint isn't mentioned
with them. The text further says (p. 2974) that its hip joint prevented
*Microraptor* from raising its legs _above_ vertical -- now that is not
surprising, so I understand why it isn't backed up with any reference to
specimens, but that's all that's said about the hip joint in the entire
As has already been pointed out, the first page implies continuity
between the plesiomorphic sprawling posture of archosauriforms and the
highly derived sprawling posture of foot-propelled diving birds
(incidentally, this includes the hesperornithiforms which aren't
mentioned even though the third author, Larry D. Martin, has worked on
them). This, laddies and gentlewomen, is a rhetorical trick. It is not
As has also been pointed out, the claimed absence of antitrochanter and
supracetabular shelf in nonavian eumaniraptorans is wrong. But lack of
familiarity with the relevant literature isn't a surprise with these people.
The assertions at the end (that *M.* was able to climb tree trunks and
basically unable to walk) have likewise been addressed. They simply
don't follow from the rest of the paper, and aren't accompanied by a
Fig. S1 shows a model of a *Microraptor* skeleton with legs sprawled 90°
from vertical -- the pose that the SVP meeting presentation by Burnham
et al. 2008 had claimed in all seriousness, but that the text of the
present paper does _not_ claim anymore. Unfortunately the resolution of
that photo isn't good enough to say anything about whether the hip joint
is painfully dislocated. But anyway, have a look at the foot, and laugh.
The metatarsus is twisted by 90° so its plantar side faces ventrally
instead of caudally! Alexander et al. took the ankle apart and put it
back together in an utterly laughable position! :-D This was kept in the
model, as shown in fig. S4.
In the same photo, the 1st toe opposes the others, and the claw on the
2nd toe is way too small while the toe as a whole is too long, as the
photo of the holotype (fig. S2) shows.
The text says at least some specimens support the claim that the tail
fan was V-shaped. Then how did fig. S4 happen, and why does it claim to
show "the actual size and shape of feather impressions on fossil specimens"?
(Never mind that the feathers aren't preserved as impressions.)
Three sad options: either this paper wasn't peer-reviewed (in which case
something is wrong with "direct submission"); or it was, and the
referees recommended publication without changes to the points mentioned
above, in which case it's a rather spectacular failure of peer review --
perhaps all reviewers thought the support for all those strange claims
was given in the supp. inf. and didn't bother reading it --; or the
referees recommended against publication (maybe that's why they're not
thanked???), but the guest editor accepted the manuscript anyway.
All three are disturbingly uncharitable. Can someone suggest more
possibilities of what could have happened?