[Taxacom] morphology in molecular phylogeny

[John Grehan]

Unbelievable though it may seem it is definitely pervasive. Those who
have been on TAXACOM for a while will be familiar with my campaign
regarding the assumed reliance on molecular similarities as the final
word on the evolutionary relationships between humans and great apes and
the fact that the molecular chimpanzee relationship is contradicted by
morphology which points to the orangutan. The morphological evidence is
also consistent with the fossil record (which has to be totally
disregarded if molecules are the final word since the morphology gives
the 'wrong' answer). 

Some theorists invoke the 'total evidence' principle which I thing is ok
where apples are being compared to apples, but I do not at this time see
a direct correspondence between the comparability between a single
character with four states (or four characters) at different sites on a
molecule being necessarily cladistic in the way morphological characters
are (but acknowledging that others on TAXACOM to not agree).

Whatever the case, it is a fact for primates, for example, that the
quality of comparative morphology in modern times for living taxa is
actually worse than it was in the 1950's (this came out by the fact that
I could not get comparative information on the simplest and most obvious
features of morphological and behavioral biology for primates). We are
actually witnessing regression of a science.

The worst example of disregard for comparative morphology occurs in
hominid systematics (which is in a dreadful state of overall disrepair)
where there is a paucity of good comparative descriptive information on
morphology and a total indifference by some hominid specialists for
nomenclatural conventions by withholding access to holotypes
(effectively rendering their work beyond science), a practice seemingly
supported by NSF which funds these 'scientists'. Perhaps it is no
coincidence that these morphologists also believe in the final authority
of molecular similarity.

I'll step down from my bandwagon now.

John Grehan



> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Maarten Christenhusz
> Sent: Friday, January 19, 2007 10:04 AM
> To: taxacom at mailman.nhm.ku.edu
> Subject: [Taxacom] morphology in molecular phylogeny
> 
> Dear all,
> 
> To continue the discussion about the destruction of evolutionary
> morphology in modern biology and systematics, I also think it is
> unbelievable that anyone can do taxonomy on a group solely based on
> molecular data, without taking the morphology into account. I would
think
> that the samples used were identified by someone (who seldomly gets
> acknowledged for doing so correctly) using morphological characters
> (provided in keys or species descriptions). Many moleular people just
> believe the identification given with the specimen, without checking
if
> these are correctly identified.
> I also noticed that mostly when a phylogeny at the family level is
> attempted, the type genus is neglected, and these families have not
always
> been tested for monophyly. This can be seen even more commonly at the
> generic level, where at least the type species of the genus should be
> included, before any taxonomic conclusions can be drawn.
> 
> Maarten Christenhusz
> University of Turku, Finland
> 
> 
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