re: Pisanosaurus and Effigia

["Jaime A. Headden" <qilongia@yahoo.com>]

David Peters (davidpeters@att.net) wrote:

<I should eye with suspicion, I suppose, all present and future analyses that
report a boot on the pubis of Effigia. It may or may not be there. Or for that
matter, we should all eye with suspicion any matrix that uses any published
matter for data. Right? Or for that matter, we should eye all data matrices no
matter their source with suspicion. After all this is science and we should
test everything. Trust nothing.>

  ... but observation that has been verified, I should add, independantly, but
other means than the initial observation.

  My examination of fig. 42 (pg. 50) in Nesbitt, 2007 (_Bulletin of the
American Museum_ 302) confirms the presence of a large and hook-like pubic
boot. If the argument above is meant to be sarcastic, this doesn't seem to be
the case. 

<And if anyone can appress the metatarsals of Effigia to form a theropod-like
metatarsus, I'd like to see it. From what I can gather, I and IV fall slightly
behind II and III with gaps present despite strongly overlapping proximal ends,
again, as in sister taxa. This one could actually be a judgment call. And
again, it matters little because proximal sister taxa go both ways.>

  Presumably, the proximal view of the articulated metatarsals (fig. 47a, pg.
55) will not provide the same view of metatarsals as seen in fig. 47b of the
same page. In fact, to attain the latter view, as can be seen by viewing the
proximal spaces between the metatarsals, they are in fact not closely
appressed. When articulated fully, each shaft will be slightly rotated about
its axis from the central metatarsal (mtIII) and be viewed slightly at an
angle, so that each distal condyle will orient its corresponding digit outward
from the main axis. This view when corrected will result in more closely
appressed metatarsals than fig. 47b will produce. This is due to the
metatarsals being lain in direct dorsal aspect, regardless of oriention. I
suspect a direct examination of the fossils (or a conversation with Sterling)
will confirm this statement.

  Cheers,

Jaime A. Headden
http://bitestuff.blogspot.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


      
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