Barking up the wrong ape

[John Grehan]

Here's another recent paper by Schwartz that illustrates why I get the
impression that the quality of systematics in hominid phylogeny is
really, really bad. The following article makes a detailed case for why
hominid phylogeny is in critical need of a comprehensive overhaul. The
systematic situation for hominid and hominoid fossils seems to me to be
so bad I am surprised that creationists have not had more of a field day
with the subject in their efforts to discredit evolution (perhaps
because those who are questioning the evolution and the fossil record
are not systematists either).

Schwartz, J.H. 2004. Barking up the wrong ape - australopiths and the
quest for chimpanzee characters in hominid fossils. Collegium
Antropologicum 28. Supplement 2: 87-101.

For those interested I have excerpted some of the points that were
raised:

1. Ramapithecus (=Sivapithecus) was once regarded as hominid because
when it was known only from the lower jaw the thick dental enamel and
low cusped molars which were seen to characterize proper hominids.
Discovery of the Sivapithecus skull showing features that appeared
synapomorphic with orangutans created a dilemma from which the field of
paleo-anthropology never recovered as it was impossible to reconcile the
orangutan-like facial and dental features with prevailing theories of
human-African ape relationship.

2. The synapomorphies for Ramapithecus/Sivapithecus were deemed
sufficient to remove other thick-enameled hominoids from potential
hominid ancestry and reassigning them to an orangutan clade (e.g.
Gigantopithecus, Ouranopithecus, Rudapithecus).

3. Dryopithecus is a wastebasket taxon.

4. Molecular anthropologists denied a role to morphology in deciphering
phylogenic relationships and yet paleonanthropology and paleontology in
general can only be pursued through comparative morphological analysis.

5. Paleoanthropologists face a schizophrenic situation of, on the one
hand, accepting without question a human-chimpanzee sister group based
on molecular evidence, and on the other continuing to speculate about
the affinities of fossil taxa.

6. Australopith supraorbital regions are mounded, which is a character
otherwise characteristic of orangutans, Sivapithecus, Ankarapithecus,
Lufengpithecus, and Ouranopitheucs, and argued by some as a synapomorphy
for an orangutan clade.

7. The upper palate of all australpiths that have a break down the
midline show a posterior thickening of the palate - like orangutans and
their relatives, but not like African apes (which become thinner). AL
200-1a which is illustrated in the literature as showing a thinning of
the posterior palate is broken lateral to the midline and therefore may
only be showing the normal thinning of the palate to either side of the
midline.

8. Tall, oval orbits characteristic of orangutans also sometimes occur
in some Homo specimens.

9. Australopith orbits may be subs circular but they are often ovoid .

10. The anterior root of the australopith zygomatic arch faces forward
like orangutans, Sivapithecus, Ankarapithecus, Lufengpithecus, Can
Llobatares 'Dryopithecus' and Ouranopithecus (with the exception of some
australopiths where the superior portion of the anterior root faces
upward as a highly derived condition).

11. The Taung child (Australopithecus) has a long, slit like single
incisive foramen - as found in orangutans and orangutan fossil
relatives.

12. The nasal bones of orangutans, Sivapithecus, Ankarapithecus, Can
Llobatares Dryopithecus, Ouranopithecus, and Lufengpithecus are long,
and in most cases relatively narrow. They are long and narrow in
australopiths (and short in Homo).

13. Like potential members of the orangutan clade, some australopiths
show size and shape heteromorphy in the upper incisors.

14. The relationships of australopiths may indeed lie closer to other
hominids - those that currently constitute the genus Homo - but the
relationships of australopiths to one another is so uncertain that
nothing more definitive than this obvious generalization can be made at
this time (in other words all those phylogenies in journals and popular
media and web showing species relationships between various
australopiths is basically just so much junk).

15. Until fossils identified as hominid have been scrutinized further at
the pre- alpha level of taxonomy, statements concerning "who's related
to whom" are meaningless.

16. The fact that orangutan-like teeth pervade the drawers of specimens
from supposed hominid sites of the Plio-Pleistocene of East and South
African should send a strong warning about the problem of phylogenic
relationships between supposed hominid specimens.

17. Proclaimed early hominids that are either primitively
chimpanzee-like (Ardipithecus) or surprisingly unchimpanzee-like
(Sahelanthropus) are actually not hominids at all.

18. What became of thick-enameled hominoids subsequent to the Miocene?
They have become identified as Plio-Pleistocene hominids.

 

I hope to get a pdf in the not too distant future and I will announce
its availability as for the previous article.

John Grehan

 

Dr. John R. Grehan

Director of Science and Collections

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