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Re: Fossil species



On Tue, 05 Feb 2002 04:51:04  
 Ken Kinman wrote:
>     Well Steve, this has been a problem for a very, very long time.  
>However, there could someday be computer algorithms (utilizing optimality 
>criteria of information content) which could help eliminate much of the 
>arbitrariness.
>      Not sure how well they would work for fossils, but they have been 
>tested on a family of extant fishes (Caesonidae).  It contains 20 species, 
>and this family's optimal classification was mathematically determined to be 
>4 genera (two distinctive species were placed in monotypic genera, one genus 
>with 8 species, and another with 10 species).  With the added stratigraphic 
>data of fossils, I would guess the computer algorithms might be a little 
>trickier.
>     Anyway, if you are interested in quantitative methods and optimality 
>criteria, you might find it interesting:
>
>Carpenter, K.E., 1993.  "Optimal Cladistic and Quantitative Evolutionary 
>Classifications as Illustrated by Fusilier Fishes".
>       Syst. Biol. 42(2):142-154.

Ken,
Thanks for the citation.  Certainly the concept of a "genus" has been a problem 
for quite some time.  It is just that I am relatively new to 
classification/paleontology, and only in recent years have I begun to ponder 
these dilemmas.  

While a computerized method removes personal preferences, it still doesn't seem 
to be any type of solution.  Who, or what, is to say exactly what "optimal 
classification" is?  Every algorithm will be different.  Cladistics isn't 
perfect, but cladistic analyses rely on the principle of parsimony.  Upon what 
principles would these computer programs be based on?  And, yes, stratigraphy 
would probably cause many more problems.  

The simplest solution seems to be to dump terms like "genus," although I wish 
you much luck in your quest to marry cladistics and classical taxonomy.  You 
certainly have your work cut out for you...but I'll always be interested in 
hearing your latest classifications.  

To me, however, the question "what is a genus?" is more complexing than "what 
is beauty?" 

Steve

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