>I offer this in the argument of "what physical features can be used to
>determine a species," because I believe you have to take each family/genus
>individually to decide what features are determinant as well as use a
>mixture of physical traits.  For years people have (overly) relied upon
>radular characteristics - sometimes to the exclusion of all other
>characteristics.  In fact the 1866-1893 work by Troschel and Thiele has 50+
>pages devoted to classifying the Neritidae on just radular characteristics.
>The problem is, the radula can vary within a single species of nerite so
>much that it could be linked with a number of other, closely related
>species!
>
>I am not saying we need a mystical "gestalt" process for species
>identification - but we do need to look at all that is available to us.
>This includes the supposed magic bullet of DNA.  As this becomes more
>available it should be considered just another useful marker and not the
>"final " determinant.

For sure, and this goes for cladistics too... just a tool, not the be-all.
>
>And with that, I'll go back to my corner.

Don't fall into that tray of Clithon...