[Taxacom] twists and turns of molecular supremacy for paleontologists

[John Grehan]

I read with interest "The evolutionary context of the first hominins" by
Bernard Wood and terry Harison (Nature, 2011) in which they assert that
molecular supermatrix (what a great rhetorical device!) analysis based
on both on mitochondrial and nuclear genes supports the Pan-Homo
relationship, and that humans and chimps are sister taxa. But despite
this there are "substantial morphological, molecular, and behavioral
differences". Even so there are "sound logician reasons based on the
morphology (!] of their nearest modern outgroups to support the
inference that the skeleton of the chimp-human MRCA would have had more
in common with chimps than humans. 

 

The most telling section is their assertion that "shared morphology does
not mean shared history". Of course one would have to agree, but it is
interesting that the same thing is not said of molecular evidence.

 

The solution is, of course clear, that "for extant taxa, this hypothesis
(relationship between morphological similarity and genetic relatedness)
can be tested against relationships on the basis of molecular evidence."
So here they clearly subordinate morphology to molecular evidence
(ironically these guys are paleontologists working with morphology) and
morphology is so unreliable that one has to find congruence with
molecular results. They later say morphology "can produce results
congruent with the relationships generated from molecular data as long
as the anatomical regions targeted have a high enough signal to noise
ration" What a mess.

 

Now when it gets really interesting for me is when they say 

 

"Although there is overwhelming [great propaganda word, tirelessly used
by molecular advocates] molecular and morphological evidence for a
(Pan-Homo) Gorilla) Pongo) pattern of relationships among the extant
hominids" ......

 

Of course that is a dubious assertion in the light of Grehan and
Schwartz (2009) where we laboriously show that the morphological
evidence for a Pan-Homo relationship is just not there.

 

But it gets better.

 

"...selected morphological character states can be used to infer a
(Homo-Pongo...) pattern of relationships, but these are almost certainly
homoplasies"!

 

So there you have it, an admission that there is another possibility -
but the evidence is "almost" (almost?) certainly homoplasies. Why? Well
of courses because molecules are the Truth. 

 

But like that Harry Potter story about He Who Shall Not Be Named, there
is no citation! Grehan & Schwartz (20009) do not really exist. Is this
great scholarship or what? And we are guilty of "selected morphological
character states" - well yes of course as we did a cladistic analysis
that requires us to use uniquely shared features!

 

I might add some more comments for the rest of the paper later.

 

John Grehan

 

 

Dr. John R. Grehan
Director of Science and Research
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, NY 14211-1193

email: jgrehan at sciencebuff.org
Phone: (716) 896-5200 ext 372
Fax: (716) 897-6723

Panbiogeography
http://www.sciencebuff.org/biogeography_and_evolutionary_biology.php

Ghost moth research
http://www.sciencebuff.org/systematics_and_evolution_of_hepialdiae.php

Human evolution and the great apes
http://www.sciencebuff.org/human_origin_and_the_great_apes.php