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Re: When did the comsognathid lineage end? (fwd)



Rutger Jansma (fam.jansma@worldonline.nl) wrote:

<And I suspect that Nquebasaurus is also soms sort of compsognathid based
on the overall similarities between it and Sinosauropteryx +
Compsognathus, like a relatively short arm when compared to the hindlimb.
Furthermore, the pubis is very similair to that of Sinosauropteryx and it
appears to have the characteristic "fan-shaped" dorsal neural arches for
this genus.>

  The fan-shaped neural arches have been questioned by some for both
*Compsognathus* and *Sinosauropteryx* based on defining the phrase, and
may actually be a basal coelurosaurian feature as they are present also
*Deltadromeus* for the caudal vertebrae, and could corresponded to
proximal ossification of the intraspinous tendons.

<And the unnamed Solnhofen genus, which, according to some sources, might
be a new species of Compsognathid. It only comprimises of a complete skull
and a few cervical vertebrae, more might be present though, given the
excellent preservation we have all come to love from this formation and
all I had to go on was a partial photograph.>

  Viohl mentioned this in issue 17 of the journal _Archaeopteryx_, and
theat partial photograph of the skull only and the few verts shows all
that there is.

<Scipionyx is another small theropod, and based on the pubic similarities
to Compsognathus, might also be a compsognathid, but it is based on a
juvenile specimen so many other distinctive characters are not present to
code for a detailed analysis.>

  In fact, all these taxa are fairly similar, and the so-called
compsognathid autapomorphies, some of which are seen in *Coelurus* and the
nearly complete skeleton of the "coelurid" that may geta  new name, may be
symplesiomorphies of a basal radiation of coelurosaurs.
 
  The youngest "compsognathid" appears to be from the Romualdo Member of
the Santana Formation, and is therefore Aptian in age.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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

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