[Taxacom] fossil myths and molecules

John Grehan jgrehan at sciencebuff.org
Wed Nov 19 09:30:10 CST 2008


A list colleague brought to my attention a lecture by the molecular
biologist Alan Cooper as part of a Darwin series in New Zealand
(http://www.radionz.co.nz/national/programmes/the_darwin_lectures)
because of reference to the molecular relationships of humans and apes
being a more or less rock solid example of orangutans splitting off
earlier than humans and African apes. Of course this is not surprising
given the pervasive molecular avoidance of the conflicting morphological
evidence. But what did catch my attention was Cooper's assertion of the
existence of a gorilla fossil (or at least a fossil member of the
gorilla lineage) at 10 Ma and this could be used to time subsequent
divergence events. This might be a good example of where science may be
more mythology than science.

 

The 'facts' as I understand them are that there is a fossil called
Nakalipithecus nakayamai dated at 9.9-9.8 Ma. The cusps configuration
"appears reminiscent of that of modern gorillas" although "the cusps are
lower". The authors state that it "could be a close to the last common
ancestor of the extant African apes and humans" but present no
supporting evidence. The molars also have thick enamel, something no
found on gorilla molars. Another fossil dated to 10.5-10.0 Ma is
Chororapithecus abyssinicus comprising some teeth fragments with
shearing crest features that "partly" resemble the modern gorilla
condition. They state that the "combined evidence suggests that
Chororapithecus MAY be a basal member of the gorilla clade" so they
openly admit that they really don't know. These teeth also have thick
molar enamel and the authors acknowledge that it's three dimensional
structure is "reminiscent" of patterns seen in orangutans. The authors
state that there is "a coherent set of derived features hared with the
modern gorilla" although I could not find any demonstration of a set of
features uniquely diagnostic of gorillas that also characterized this
fossil.

 

In light of the above it would seem that there is no such thing as a
fossil gorilla or gorilla clade at 10 Ma so reference to such a fossil
would seem more like a myth than science (and certainly not good
systematics).

 

John Grehan

 

Dr. John R. Grehan

Director of Science

Buffalo Museum of Science1020 Humboldt Parkway

Buffalo, NY 14211-1193

email: jgrehan at sciencebuff.org

Phone: (716) 896-5200 ext 372

 

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

 

 




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