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Re: Recoded Aves introduces a lot of fog?



David Marjanovic wrote-

> But the pygostyle is preserved close to the sacrum, and very few free
> caudals are preserved. This is of course little evidence, but IMHO
> suggestive. What weighs much heavier is that *Sapeornis* was a good flier,
> better than the confuciusornithids, and surely couldn't have afforded a
> reasonable tail. Over 20 caudals, maybe (as embryos recent birds have 18
to
> 23, I've cited once), but then many must have been very short.

The sacrum is not even preserved.  The pygostle is about 30 mm from an
ilium, but an ischium is about 160 mm away from that ilium, while a free
caudal vertebra is over 200 mm away.  Though not completely disarticulated
(an arm and some vertebrae are articulated, and the posterior and anterior
elements are in the correct halves of the specimen), I don't think we can
depend on the distance between the pygostyle and ilium to determine the tail
length (the pygostyle's distal end isn't even pointing away from the rest of
the specimen).  I also doubt our knowledge of evolution and biomechanics of
tails in flight are complete enough to use those as reasons to code the tail
as being short.

Mickey Mortimer