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Re: Lumping Spinosauridae Redux



[For those of you on the PhyloCode list, this stems from a discussion on
synonymy of *Baryonyx* and *Suchomimus*, and how you can prove this
scientifically. Appologies for cross-posting, but this contains material
relevant to both lists.]

Mike Taylor (mike@indexdata.com) wrote:

<To be clear, I fully realise that you are not advocating going to these
extremes.>

  ... quite the opposite, in fact, Mickey likes genera :) ...

<But I do think this shows that you can't just rely on monophyly of the
new, broader genus when deciding whether one should be sunk into another.>

  I have a different position, one of first assignment with given
priority. If, in the course of a taxon's assignment, a species is coined
and assigned to a genus, it pertains to that genus from thenceforth. IF,
however, a species is separated from a genus and established in its own
right, it should be determined to belong to this new genus. Thus
preserving historical artifacts. However, if a species is referred to
another genus, one which is NOT new, and the species had its own unique
container (a genus) separate from this new referral, it should remain in
its own container, unless the species too is also a synonym.

  Example:

  *Aublysodon molnari* was originally designated, until at some point, it
was recognized that *Aublysodon* was not the "correct" container for
*molnari*; *A. molnari* was assigned a new container, *Stygivenator
molnari,* at which point this referral business ends. However, if
*molnari* belongs to either *libratus,* *sarcophagus,* *torosus,* *rex,*
or potentially even *bataar,* we should lose *Stygivenator* in referral of
*molnari* to one of those species as a juvenile form. The only way we lose
*Stygivenator* is with loss of *molnari* as a junior objective synonym.

  Hence, until one can prove that *walkeri* is a senior synonym of
*tenerensis,* the separation of *Baryonyx* and *Suchomimus* is just as
valid. They currently contain equivalent taxa, from the "species" to the
"genus," which Mickey himself has yet to determine _how_ these are to be
differentiated, only treated them as if they were distinct entities. This
is my idea as it stands.

  One consideration (Mike Keesey has advocated this in part for the sake
of defining "genera") is that everything above the "traditional"
species-level taxaon is not a named type of clade, but just a clade,
including "genus." In this manner, Clade={*Suchomimus*} is inclusive of
only *tenerensis,* and all other designated type species are not (this
would have to have another temporal modifier). By using the same formula,
*Baryonyx* can never include *tenerensis,* even if they were found to be
synonymous, because their definitions would mutually prohibit it. I don't
like this solution.

  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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