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re: ICZN & PhyloCode (was RE Stegosaur volume of Swiss Journal of Geosciences



On Mon, 20/9/10, Anthony Docimo <keenir@hotmail.com> wrote:


> How can it be both crap *and* valid?


With consummate ease.  A specimen can be fragmentary and/or poorly preserved, 
but nevertheless yield at least one character (an autapomorphy, or a unique 
character combination) to be diagnosed as a valid genus.  _Ceratops_ may fall 
into this category.  It's still a crap genus, though.

 

> I could understand why a person might consider a nomen dubium to be crap.


Nomina dubia are always crap.  But crappy specimens are not always necessarily 
nomina dubia.  You need only one diagnostic character to be gleaned from a 
specimen in order for it to qualify a valid taxon.


> >_Tyrannosaurus_ is infinitely better than _Deinodon_, 
>
> why is that?


Because _Deinodon_ is known only from teeth.


> > Y'know, I would use the Deinodontoidea example as a *reductio ad 
> > absurdum* to show why blindly applying ICZN rules is so 
> > counterproductive. There is just no way that Deinodontidae should be 
> > used in place of Tyrannosauridae,
>
> why not?


Tyrannosauridae has over a century of usage, and is based on none other than 
_T. rex_.


Go ahead.  Try using Deinodontidae instead of Tyrannosauridae.  See how many 
people follow your lead.   ;-)



> the fact that there are exceptions, automatically means "something is 
> rotten"?


The fact is that family-level nomenclature as dictated by the ICZN often serves 
dinosaur taxonomy exceedingly poorly.


> so...."it is bad to fix problems" AND "it is bad to leave problems 
> alone".   please make up your mind.

 
My point was that because of the clunky nature of certain ICZN rules, that 
these rules are often circumvented or ignored.  That's why Tyrannosauridae is 
used instead of Deinodontidae, despite (as Mickey notes) the latter having 
priority.  Strict application of priority would see Tyrannosauridae trumped by 
Deinodontidae.  Now, speaking for myself, I think this is a bad thing, because, 
well, I've kinda gotten used to Tyrannosauridae.  Plus, my sympathies go to 
_Tyrann
rus_ over _Deinodon_ over who should get the honor of having a family named 
after it.  
 

> wait, you were just calling for the rules being hard-and-fast and 
> applied equally everywhere.  


No, I certainly wasn't.  


> by that logic, please stop your protests about Ceratops.  experts in the 
> field have already made their choice.


Actually, they haven't.  If said experts had settled on _Ceratops_ being an 
appropriate genus to name a clade after, they would include _Ceratops_ in the 
definition of Ceratopsidae.  But they don't; not ever.  _Ceratops_ (the 
name-giving genus) is conspicuously absent from ANY published definition of 
Ceratopsidae.  That's a vote of no confidence in _Ceratops_.  Therefore, 
Ceratopsidae cannot stand.  Either include _Ceratops_ in the definition of 
Ceratopsidae, or forgo _Ceratops_ as a name-giving taxon.  You can't have it 
both ways.


It's also pertinent that those same experts have yet to decide whether the 
sister taxon to Centrosaurinae should be called Ceratopsinae or Chasmosaurinae. 
 Both Ceratopsinae or Chasmosaurinae have been used, and still are.  Again, 
_Ceratops_ is the root of the trouble, and is causing instability at the 
'subfamily' level.



Cheers

Tim