Classifying apes & relatives

[John Grehan]

I know far too little about even higher primate systematics to start on
about the formalities of classification, but I guess that won't stop me
from a making a couple of (poorly?) informed comments   On the premise that
humans and orangutans are each other's closest living relatives, I see the
possibility of two major clades:

The first is the immediate 'human' line that might include Homo and
Australopithecus, and also perhaps Kenyanthropus (whether or not it is
subsumed within Australopithecus), and Orrorin - although admittedly its
not well known.

The second is an Orangutan line. There are several fossil taxa that are
possibilities, although its also possible (and well beyond my current
knowledge to know) that some are actually part of the human line). Taxa
that might be included are Sivapithecus (well accepted as the closest
sister group to orangutans), Lufengpithecus, Gigantopithecus (both also
closely allied with orangutans), Ouranopithecus, Ankarapithecus, and
Hispanopithecus.

The above taxa of both clades share thick dental enamel, a single incisive
foramen (where known), and lack or have poorly developed molar cingula. I
haven't had a chance yet to learn about the shoulder girdle which also
exhibits Human-Pongo features.

Outside these clades things get a bit more fuzzy. There are two taxa -
Kenyapithecus and Afropithecus with thick dental enamel, but Afropithecus
has two incisive foramena and well developed molar cingula, and then there
is Rudapithecus with thin dental enamel, a single incisive foramen, and
lacking molar cingula.

Then there are three other taxa with thin dental enamel for which the upper
palate is not known at all or well enough to determined the incisive
foramen - Equatoriaus (reduced molar cingula), Sahelanthropus (molar
cingula?), and Ardipithecus (molar cingula?).

That's my current speculation. Its frustrating that the upper palate is
either unknown, or too poorly preserved to confirm the incisive foramen in
several taxa.

John Grehan

At 07:56 PM 5/23/2003 +0000, Ken Kinman wrote:
>Dear All,
>     Well since we are on the subject, here is the part of my "sketchy"
>preliminary primate classification showing how the main families of apes and
>relatives may have split off.  I recognize broader (fewer) families than
>most workers.  Family Pongidae (great apes excluding "hominids sensu
>stricto") is obviously paraphyletic.  The recently described genus
>Kenyanthropus is placed within Australopithecus.  Orrorin is too fragmentary
>and controversial to place in either Pongidae or Hominidae with any
>confidence.
>     Anyway, if a chimp-human clade is disproven, the {{Hominidae}} exgroup
>marker would just need to be moved up closer to Pongo.  Once again, this
>kind of modular approach to classification gives us flexibility without
>sacrificing stability.
>
>  1  Cercopithecidae
>  2  Propliopithecidae
>  3  Pliopithecidae
>  4  Proconsulidae
>  ?  Oreopithecidae
>  5  Hylobatidae
>  6  Pongidae
>        1  Dryopithecus
>        ?  Ouranopithecus
>        2  Lufengpithecus
>        B  Sivapithecus
>        C  Pongo
>        3  Gorilla
>        ?  Samburupithecus
>        4  Pan
>        5  {{Hominidae}}
>_a_ Hominidae
>        1  Ardipithecus
>        ?  Sahelanthropus
>        2  Australopithecus
>       _a_ Homo
>
>              ----- Cheers,
>                      Ken Kinman
>
>_________________________________________________________________
>MSN 8 with e-mail virus protection service: 2 months FREE*
>http://join.msn.com/?page=features/virus

Dr. John Grehan
Director of Science and Collections
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, New York 14211-1293
Voice 716-896-5200 x372
Fax 716-897-6723
jgrehan at sciencebuff.org
http://www.sciencebuff.org/biogeography/Panbiogeography/Panbiogeography-Gate.htm
http://www.sciencebuff.org/HepialidaeGate.htm