Re: Time for PT rules?

["Jonathan R. Wagner" <znc14@TTACS.TTU.EDU>]

Nick Pharris wrote:
>Since there are no hard and fast rules yet in phylogenetic taxonomy, we
>have an excellent opportunity to set up a rational, well-defined system
>here.
        Except that "here" is a non-publically available, non-peer-reviewed
format which is not frequented by a large number of phylogenetic
taxonomists. This makes "here" an inappropriate venue for determination of
such a system (what an hypocrite I am!). Additionally, I'm not sure that
such a discussion falls under the perview of the dinosaur list. I personally
am more than willing to discuss such matters off-list.
        Rest easy, I'm positive there are people working on such things...

>(Alas, I realize that paleontologists in particular are an
>independent lot who tend to chafe at rules ;-)
        Well, that and the traditional lack of rules for higher taxa. How
many times has George Olshevsky balked at the idea of priority for
suprafamilial taxa?        

>I am all in favor of using multiple exclusive anchor taxa in stem-based
>definitions.
        I have argued this many times on the list (to toot my own pathetic
little horn, I actually invented the term "anchor taxa", AFAIK). There are
some, however, who seem to believe that no more than two anchors are
appropriate in PT. I have yet to hear a conclusive statement regarding this.

>For instance, Ornithomimosauria could be defined as
>"everything closer to _Ornithomimus_ than to _Troodon_ and closer to
>_Ornithomimus_ than to _Tyrannosaurus_." 
        "_Ornithomimus_ and all taxa sharing a more recent common ancestor
with _Ornithomimus_ than with _Troodon_ or _Tyrannosaurus_, " is the
formulation considered most pleasing (at least under the current
Buchholz/Wagner methodology). This is represented as: Ornithomimisauria == {
_Ornithomimus_ > _Troodon_, _Tyrannosaurus_ }

        Oh boy, I hope Dr. Holtz doesn't see us messing with
Ornithomimisauria on the list... :)

>That way, the three arctomet
>branches are kept separate even if their interrelationships get shuffled
>around.
        This was a particular whippin' stump of mine a while back when a
dataset of mine produced (Troodontidae, (Ornithomimidae, Tyrannosauridae)). Eek!

>Similarly, multiple *inclusive* taxa can be used in node-based
>definitions.  That way, for example, the allosaurs, sinraptorids, and
>carcharodontosaurs can all be kept in the Allosauroidea regardless of who
>is closest to whom.
        Another whippin' stump of mine actually. I remember when Nick had
his own ideas... ;)

>Perhaps there should also be a proviso for redefining groups in the light
>of later discoveries.
        Noooooooooooooooooooooooooooooooooooo nonononononononononononono!
That, my dear friend, is a typological concept, i.e. what we are trying to
*avoid* in P.T. You are saying "I know what this taxon *should* contain,
because I have an idea in my head of what it *is*, and if the phylogeny
overturns this, we *must* redefine." Not at all what DeQ and G meant.

>We have a profusion of endings for names of taxa:  -morpha, -opsida,
>-formes, -idae, -inae, -oidea, etc.  Perhaps some of these could be
>restricted to stem-based or node-based usage, in the interest of clarity
>and as an aid to memory.
        I think someone has suggested something similar. I know I wanted at
some point to restrict established family names to stem-based taxa with
multiple exclusive anchors in order to better ensure access to the
literature. The only similar suggestion I know was DeQ and G suggesting that
-gens be used as the stem for total groups (a taxon defined as a crown clade
and all taxa sharing a more recent common ancestor to that crown clade than
to the next most closely related crown clade).
        Anyway, I don't think this'd fly. Besides, you'd have to suspend
priority and re-organize everything, and each set of workers (fish, mammals,
NADs, avian dinosaurs, etc) would do theirs differently. Yucky!

>For instance, -idae could be used for a
>low-level node-based grouping,
        Not keen on the node-based family, except in the case of Hadrosauridae.

>and -oidea for the stem-based grouping that
>contains it.
        Cute.

>(As much as I am in favor of abandoning Linnaean ranks, I still prefer to
>have my -oideas above my -idaes above my -inaes.)
        Me too, oddly enough. Oh well.

>Finally, as a speaker of Greek and Latin, I am all in favor of quietly
>correcting malformed names like "Ceratopsia."
        Not here. Quite fond of that, very well established, sounds better.
I'm gettin' crotchety in my young age.

>The "i" in Maniraptora, BTW, is not a problem.
        Good, because I don't really care to see it changed.

>Much as I idolize Paul Sereno, his Latin is usually terrible.  I think all
>bio and paleo types could benefit from a little Latin background.
        Many of us do have one, but I personally am forced constantly to
consult a latin dictionary anyway. Besides, this is why folks like George O.
are so valuable...

        :)
        Wagner
--------------------------------------------------------------------------------
     Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
 "Only those whose life is short can truly believe that love is forever"-Lorien