Re: BAD vs. BADD (was: Re: Most popular/common dinosaur misconceptions)

[mike@miketaylor.org.uk (Mike Taylor)]

David Marjanovic writes:
 > Secondly, ranks are not just merely useless. They are actively
 > misleading.  I'm sure you've seen many studies that count genera or
 > families and pretend to have measured biodiversity, when in fact
 > they've measured the opinion of one particular splitter or lumper
 > and nothing else! Such studies have even been conducted by people
 > who elsewhere emphasize that ranks have no real meaning.

Yo!  *Raises hand*  Over here!  :-)

I've done exactly this -- compare the explicitly phylogenetic context
of Taylor and Naish 2005 with the genus-level diversity survey of
Taylor 2006:

        Taylor, Michael P., and Darren Naish. 2005. The
        Phylogenetic Taxonomy of Diplodocoidea (Dinosauria:
        Sauropoda). PaleoBios 25 (2): 1-7.

        Taylor, Michael P. 2006. Dinosaur diversity analysed
        by clade, age, place and year of description.
        pp. 134-138 in Paul Barrett (ed.), Ninth international
        symposium on Mesozoic terrestrial ecosystems and
        biota, Manchester, UK. Cambridge Publications,
        Cambridge, UK. 187 pp.

Why did I do it?  Because I don't see any alternative way of surveying
diversity.  I'll be delighted to hear one if you have something up
your sleeve, though :-)  Any diversity survey has to count occurrences
of_some_ unit of diversity.  What, then?  Counting individual
specimens is clearly assessing something different from diversity;
that leaves the option of counting occurences of some taxonomic unit.
While an argument can be made that species are "more real than" genera
for extant taxa (in which the biological species concept can be
tested) you will surely concede that for dinosaurs at least the
species-level taxonomy is more arbitrary that genus-level, and that
the wild variations in speciosity of different genera represents a net
signal loss.

So I counted genera.  What would you have done?

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor  <mike@miketaylor.org.uk>  http://www.miketaylor.org.uk
)_v__/\  "Conclusion: is left to the reader (see Table 2).
         Acknowledgements: I wrote this paper for money" -- A. A. Chastel,
         _A critical analysis of the explanation of red-shifts by a new
         field_, A&A 53, 67 (1976)