[Taxacom] Intuition in taxonomy

Torbjørn Ekrem Torbjorn.Ekrem at vm.ntnu.no
Wed Mar 4 01:27:58 CST 2009

Hi Bob

what you state here sounds a lot like 'underlying synapomorphies', a
term coined by Ole Sæther in the late 1970s. The use of such arguments
as true synapomorphies are problematic because it is difficult to
positively identify the potential of a structure if it is not present.
(unless you find the gene regulating the feature) . Thus, there has been
a lot of debate around the value of 'underlying synapomorphies' in
phylogenetic analysis. Although I think this type of characters are
problematic to use a priori, I agree with you that they could be used a
posteriori to explain certain character distributions on established

Best regards,

Dr. Torbjørn Ekrem
Vitenskapsmuseet, NTNU 
Seksjon for naturhistorie 
7491 Trondheim

Museum of Natural History and Archaeology
Norwegian University of Science and Technology
NO-7491 Trondheim, Norway

Tel: +47 73 59 78 12
Email: Torbjorn.Ekrem at vm.ntnu.no
Web: www.ntnu.no/~torbjoe

> 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.

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