Re: Podokesauridae, Problems of Nomenclature Returned

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

Mickey Mortimer (Mickey_Mortimer11@email.msn.com) wrote:

<Just for the record, the latest comparison of Podokesaurus to Coelophysis
was Colbert's (1964), which wasn't very extensive.  He found two
differences- dorsal neural spines anteroposteriorly shorter; ischium
differently shaped.  The first is a good distinction (assuming it's real),
but the second certainly needs to be more precise.  Contrary to Jaime
Headden's claims, these have never been shown to fall within the
individual/ontogenetic variation of Coelophysis, nor are they obviously
size-related.>

  Actually, Colbert showed several plots of limbs that indicated the
material was either paedomorphic or juvenile. It logs as a small
*Coelophysis*. However, stepping away from that taxon, I can support that
ischial shape is not nearly so congruent in a single taxon as one might
think. In *Allosaurus* and *Syntarsus*, ischia actually vary a little bit
in both size of the distal expansion, form of the obturator plate/prong,
curvature and flexion in the shaft, and relative size compared to pubes.
They are hardly static measures. Such variation is considered typical in
the group and hardly comparative to taxonomy. In the some 30+ odd
individuals recovered by Raath in Rwanda (Rhodesia), the *Syntarsus*
varied a good deal in specific features of the girdles and limbs, though
constants includes the femoral head, tarsal morphology, pubic obturator
openings, and coracoid shape, if I recall correctly.

  For all intents and purposes, the acknowledged (now late) expert on
*Coelophysis* considered it to be a possible junior synonym, though
possibly a distinct species. No other systematic consideration of the
taxon, including Sereno, has found that the specimen is fairly valid, and
I would not take to it much. However, be pleased as any will and examine
the material personally, I want to, but I doubt much will come of it.

<However, Coelophysis desperately needs to be redescribed>

  You mean, Colbert, 1989 wasn't sufficient?

<and illustrated>

  uhm, same as above ... to death I think. Plus Paul and Tykoski, and...
eh, well, leave that alone.

<As for the main issue of definition vs publication priority, I'm all for
publication.  Go Segnosauria, Podokesauridae and Avetheropoda!>

  Not to mention Cerapoda. Ornithischians get such short shrift these days.

=====
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.

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