[Taxacom] Intuition in taxonomy

Bob Mesibov mesibov at southcom.com.au
Tue Mar 3 18:20:47 CST 2009

According to the manual for the Zanderian Zetetoscope (TAXACOM, 28
January 2009)

"Press the Orange button. Sort specimens and types into groups using
whatever techniques seem appropriate.
Press the Yellow button. Decide evolutionary relationships using
whatever techniques seem appropriate.
Press the Green button. Name smallest distinctive groups that seem
evolutionarily coherent with the earliest name of an included type, then
put other type names into synonymy, and arrange a hierarchy of groups
using similarity and avoiding convergence with whatever techniques seem

It seems to me that intuition applies in pushing the Yellow button. A
zoologist colleague of mine says

"If I find a homology that is so detailed and so complicated that I have
one of those 'Bring me the tree of life! I have found a node' moments
then I have had a good day."

His intuition here is that a particular synapomorphy occurs because the
terminals inherited it from a common ancestor; the structure did not
evolve de novo in distantly related lineages. The more detailed and
complicated the synapomorphy, the stronger the intuition.

Sure, 'de novo' appearances might be possible for complex structures if
these are hidden in the genome and turned on holus bolus by some
regulatory gene. In other words, all the tools for making the structures
might be present but might not be consistently expressed in descendant
lineages. IMO this doesn't invalidate the Yellow intuition, it just
pushes the node of common ancestry further up the hierarchy.
Dr Robert Mesibov
Honorary Research Associate
Queen Victoria Museum and Art Gallery
and School of Zoology, University of Tasmania
Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
Ph (03) 64371195; 61 3 64371195
Webpage: http://www.qvmag.tas.gov.au/mesibov.html

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