Re: Crown groups

["Jonathan R. Wagner" <jonathan.r.wagner@mail.utexas.edu>]

> However, I was questioning the wisdom of
> constructing naming conventions around these crown clades, especially the
> use of the Pan- prefix.

Yeah, that gives me pause too. I am not really excited about renaming every
"total group." To quote my comments from a recent off-list message (can I
quote myself?):

"... Tim Rowe pointed out that [the Pan- convention] means that even a
non-expert will be able to quickly and concisely associate name with
definition. Assuming you know the accepted "higher" names for at least one
taxon containing every extant species (not too bad, since most of it can be
swept into Archaeobacteria and Eubacteria, you can actually give a taxon
name for almost any fossil form without knowing ANY of the fossil taxonomy.
I hate to say it, but I find this compelling."

So it may be unpleasant to give up Synapsida, but we gain the ability to
more effectively communicate with people who weren't familiar with the term.
Is it worth it? I'm not entirely sure. After all, "they" are already getting
crown clades, maybe paleontology should get to keep something!


> SimilarIy, having the name 'Mammalia' anchored to the node of the crown
> group will not change the imprecise and often subjective usage of the word
> 'mammal' in the scientific literature.  I have a feeling that
_Morganucodon_
> will continue to be called a mammal, even if it lies well outside the
crown
> group.  Ditto for _Eryops_ being an amphibian.

I partially agree on amphibian as a vernacular term; it has traditionally
referred to a grade, and, like pelycosaur, it is sometimes useful to retain
that usage colloquially. However, unlike with pelycosaur, I would refrain
from using it in scientific literature, because it corresponds to a named
taxon with a different content. I am similarly wary of reptile; I will use
it in the paraphyletic sense when talking to the public, but even then I
usually qualify it as including- or excluding birds. Bird is easier, because
there is no taxon Birdales to confuse the situation. I remember Chris Brochu
pointing out bemusedly on this list that the "supercroc" wasn't really a
"croc." Here I draw the line... it is not a crocodile, and not a
crocodylian, but I have absolutely no problem referring to any member of any
taxon with the croc- stem as a "croc," and it is a croc-form croc-morph.
"Mammal' is like "amphibian," but you run risk of offending paleomamalogists
no matter what you do. I wouldn't call Morganucodon a "mammal" in front of
my advisor. Heck, I got lambasted yesterday to talking about "saber-toothed
tigers," even though I am well aware they are not tigers (the absence of a
forged steel blade and a basket-hilt on the dentition is apparently not an
issue...). However, some people would get pretty hot is you said it isn't a
mammal.

BTW: I DO feel Lissamphibia should be abandoned. For one thing, it was
originally coined to *exclude* frogs (!). Second, if one follows the
crown-clade convention, Amphibia is the appropriate name for the extant
'phibs, with all the justifications that go along with crown-clades. Third,
who the heck knows what a "lissamphibian" is? It is not a very widely-used
term outside paleontology, AFAIK.


Wagner