Re: Miocene and Pliocene apes familiy tree?

HARRY R. ERWIN (herwin@osf1.gmu.edu)
25 Jul 1995 15:14:44 GMT

Alex Duncan (aduncan@mail.utexas.edu) wrote:
: In article <herwin-2307951648330001@192.0.2.1> Harry Erwin,
: herwin@gmu.edu writes:
: >>

: Harry, I'm going to ask you to dig into your database and answer some
: questions for me. I want to make it clear that I'm not questioning your
: database or its results, but am genuinely curious what answers you have
: available for some of these questions. I'd dig into your database
: myself, but you know your way around in there, and I don't, so...
: >
: >G. seems closer to Pongo.
: >
: Than Siva? What synapomorphies aren't also present in Siva?

This one surprised me the first time I saw it, too. I know you're an
expert on this clade, so I'd be interested in your opinions here. The
database splits the clade at this point based on male weight--a heavy
group (P and G starting at 70 kg and going up to 140 kg) and a lighter
group (heavy and light Sivapithecus and Lufengpithecus in the 40-50 kg
range, which was fairly nominal for ground apes of that time). I've tried
to minimize the importance of weight, but these differences are
significant. Note that there are other features that the database says
_could_ have been synaptomorphies, but I trust them even less.

: >> I don't think anyone really knows what to do w/ Kenyapithecus anymore.
: >> It shows remarkable dental similarities to Sivapithecus, but I don't know
: >> that anyone is comfortable with placing it in the Siva/Pongo clade. Most
: >> of the material is dental, mandibular, or maxillary.
: >
: >K. seems to be the sister group of the Pongines.

: I assume you use pongines to mean Siva/Giganto/Pongo?

Yes, although that's non-standard.

: What
: synapomorphies link Kenyapithecus w/ the pongines?

Development of the inferior transverse torus (Proconsul lacks), maxillary
sinus (?), reduced emphasis on canine honing. Please note that this
reflects the application of parsimony in ways I'm uncomfortable with. I
haven't scrubbed this part of the database recently, and I have new data
to enter from some recent papers.

: I've always thought
: the teeth were dead ringers (though I think K. teeth are more likely to
: retain a cingulum), but never could quantify my observation, since I'm
: not a dental dude.

This is part of the new data.

: >> Dryopithecus is a controversial genus. It almost certainly lies either
: >> just within the large ape clade, or as a sistergroup to the rest of the
: >> large apes. Some of the premaxillary/maxillary anatomy looks "African
: >> hominoid", but there are other features that may indicate relations w/
: >> Siva/Pongo. As is usually the case, more material is needed.
: >
: >D. appears to be the sister group of the AA clade, with the Pongines being
: >the sister group of the Dryopithecines.

: Are you using "Dryopithecines" as the name of the clade containing
: Dryopithecus and African apes? I suspect I know what the synapomorphies
: are here, but what comes out of your database?

Yes on the use of the term "Dryopithecines". The synaptomorphies are
reduced sexual dimorphism in the canine teeth (Oxnard), increased relative
size of anterior dentation, change in diet towards frugivory, stepped
premaxillary, and browridge/glabella development.

: >> Oreopithecus is weird. It almost certainly lies WITHIN the extant
: >> hominoid clade (although there have been claims its a cercopithecoid).
: >> It shows similarities to several different extant groups, including
: >> gibbons and humans. I don't really think anyone knows what to do with it.
: >
: >The database likes the gibbons as a sister group of O., and O. as the
: >sister group of the Kenyapithecines.

: If I'm not mistaken, this would mean that you've broken up the large ape
: clade, and placed orangs in a clade w/ gibbons, since Kenyapithecus is a
: sister clade to Pongines.

That tends to change with the phase of the moon (due to data quality). The
very latest tree has a Pongine/Dryopithecine clade. It still likes the
Oreopithecus/Hylobates link, and has that emerging just below Kenyapithecus.

: >> Proconsul IS NOT considered a common ancestor of the great apes and Homo,
: >> or even of all extant hominoids. It is too primitive, lacking many
: >> derived features shared by all living taxa. It is a sister clade to all
: >> extant apes.
: >
: >Yes. The database has the pliopithecines as the sister group of the
: >cercopithecines and the pair as the sister group of the proconsulids
: >(etc.).

: I was under the impression that pliopiths were to primitive to be INSIDE
: the extant catarrhine clade. They have only a partial tubular tympanic.

The tubular tympanic evolved several times. Prohylobates (a primitive
cercopithecine) still had a ring.

: If you clade them with cercopiths, then cercopiths and 'noids would have
: had to develop this feature independently of one another. What
: synapomorphies link pliopiths and cercopiths?

Not much. They're linked in being more advanced than the Fayum primates
(semimolarized premolars, carotid artery entry, elbow stability) and not
being apes (loss of tail, further molarization of premolars,
encephalization). The split towards Pliopithecus involves increased
arboreality, while the cercopiths became more terrestrial leaf-eaters.
Application of parsimony then drives them together. The database doesn't
think much of the cercopith/platyrhine link, although I think it's wrong
there. Obviously I need to keep adding (and correcting!) data.

: >> The best candidates for common ancestry of African 'noids (including
: >> humans) are Dryopithecus and Ouranopithecus (= Graecopithecus?).
: >> Ouranopithecus especially shows potentially apomorphic features (African
: >> pattern premax/palate articulation, well-developed supraorbital tori)
: >> that link it with African apes. There was a recent suggestion that
: >> Ouranopithecus is in fact a sister group to gorillas, and the discoverers
: >> of much of the recent material make a reasonable case for Ouranopithecus
: >> being the earliest hominid (I use "hominid" in the traditional sense
: >> here).
: >
: >Yes. My DB suggests it's about as far from Gorilla as P. paniscus is from
: >P. trog. That's probably wrong, given the lack of post cranial data.
: >
: >>
: >> Another very interesting Late Miocene (~8 Myr) hominoid is Motopithecus
: >> from the Samburu Hills of Kenya. The genus is based upon a single
: >> maxillary fragment that superficially looks a great deal like a gorilla.
: >> However, the enamel is thick.
: >
: >Samburu hominid?

: I think it has been referred to as a hominid, but there is no good
: evidence (that I know of) to link it w/ humans & australopiths.

OK. It seems to be near Ouranopithecus.

--

Harry Erwin

Internet: herwin@gmu.edu 

Home Page: http://osf1.gmu.edu/~herwin (try a couple of times)

PhD student in comp neurosci: "Glitches happen" & "Meaning is emotional"