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Re: tooth counts in systematics



At 9:25 -0400 12/4/99, Joshua Smith wrote:

>chris brochu wrote:
>>
>> You've got some great points here, but they actually focus on two
>> independent issues.
>
>       Yeah, that doesn't surprize me at all...
>>
>>  One of them is intraspecific variation.  Norell's talk at the Ostrom
>> Symposium gently chastized all other previous theropod systematic
>> studies for ignoring (or miscoding) interspecific variation, e.g. by
>> coding a large multispecific group with a single character state, and I
>> think we'll see more rigorous approaches to this in the future.
>> Intraspecific variation is a different matter, and as we've discussed,
>> there are ways of handling it - provided it's made explicit in the first
>> place.
>
>       I hope Mark doesn't take offense at this, but I thought that that
>was the best talk I have heard him give.  He said a lot of things that I
>had been waiting to hear a systematist say.  Honestly though, I didn't
>expect him to be the source of it.  I was very pleasently surprized.

[snip]

>       Not much that I can say about all of this except that I (?predictably)
>agree completely.  Character description/discussion has been my principal
>anti-cladism bitch for a while now (ask Holtz about long days in the
>Lance of characters, beef jerky, and Simpson's quotes...).  There are
>several sorts of variation here that need to be accounted for in
>analyses, but I understand quite well the very real editorial problems
>associated with character matrices.  Maybe places like JVP et al. are
>just not the vehicles to present these sorts of works and as such the MCZ
>or YPM bulletins need to be revisited more.  I don't know.  I will be
>pigheaded though and maintain that these issues of character
>desciption/discussion and handling of intra/intertaxonomic variation need
>to be addressed if we are going to get theropod systematics beyond the
>"flavor of the month" stage that it seems to be in right now.

And all that leads right back to the old clumper/splitter debate.  You
can't decide what intraspecific/intrageneric variation is without first -
often quite subjectively - deciding just what makes a species/genus.


Laurie Nyveen                                  lawrence@dsuper.net
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