- Samburupith = part of maxilla IIRC (no evidence of bipedality)

Open environment. Thick enamel.

I don't see the connection: capuchins & orangs live in closed
environments.

Hominoid thick enamel probably arose in forests (Griphopith), possibly in
coastal forests (eg, Peter Holec & Robert J Emry 2003 Ch.24 "Another Molar
of the Miocene Hominid Griphopithecus suessi from the Type Locality at
Sandberg, Slovakia" Bull.Am.Mus.Nat.Hist.279:625-631).

- Ouanopith // robust apiths (wetlands, some KWing features)

Hey Marc, wait a minute. Ouranopith is EXTREMELY open
environment,
and extremely thick enamel. Robust Apiths came much later (Ouranopith at
the
time just before the emergence of grass, and robust apiths A LOT MILLION
years later).

Were there reed sedges at the time, Mario?

Apiths probably partly fed on parts of sedges (eg, M.Sponheimer cs.2006
Science), bamboo (L.Du Brul 1977 AJPA 47:305), papyrus P-F.Puech 1992
Scanning Microscopy 6:1083) etc., not on grasses (this requires a
different sort of dentition & wear, cf. Geladas etc.).

But all this has nothing to with Homo: Ain-Hanech Algeria, Dmanisi
Georgia, Mojokerto Java... 1.8 Ma. --Marc

Of course. But Homo HAS something with that. -- Mario

Homo appears +-1.8 Ma at the coasts of the warm regions of the Old World.
That is where Homo began. That is what AAT is about.

BTW, baboons use kopjes in savanna, and geladas use cliffs.

Yes, and both are very different from us, don't you think? Any
parallels you see?

They are baboons, monkeys of open spaces. Even such non-adapted
climbers (primates) can use cliffs. But, they have to be adapted for
quadrupedal running in open spaces. In my scenario, we should be
adapted for fast climbing of cliffs, as well as for running downhill.

Also, they have big canines and large groups. I don't think
they
climb cliffs in a hurry. They are only using it for sleeping, I
believe.

Do humans have parallel features to cliff-hangers or hill-down-runners,
Mario? --Marc

No. I don't see any animal that lives this kind of lifestyle.

IOW, nothing sensible can be said about this.
Hardy's theory OTOH is based on SC fat, fur loss, aligned body etc.

Of course. And it is a good one. But, I am talking about bipedality.
This has no direct connections with SC fat and fur loss. But it has
something with aligned body.

Possibly some monkeys that live in hilly regions could have the similar
conditions for downhill running.
Your version of AAT has parallels in Proboscis monkey and
Oreopithecus. None of them show similarity to bipeds because of that,
although they are completly immersed in that kind of lifestyle.

http://en.wikipedia.org/wiki/Proboscis_Monkey
³While wading, the monkey uses an upright posture, with the females
carrying
infants on their hip. Troops have been filmed continuing to walk upright,
in
single file, along forest trails when they emerge on land, the only
non-human mammal, with the exception of gibbons and giant pangolins, known
to use this form of locomotion for any length of time²

Algis says that all the apes wade bipedaly. So, it isn't strange
that Proboscis is wading bipedaly, and why shouldn't it? OTOH, gibbons are
bipedal on land, although they don't wade.

But, Harcourt-Smith/Aiello issued a paper called "Fossils, feet
and
the evolution of human bipedal locomotion" (2004). They named only two
current hypotheses that they think are valid today:
"a knuckle-walking ancestor was proposed by Washburn (1967) and
has
recently been championed by Richmond and colleagues (Richmond & Strait,
2000; Richmond et al. 2001) on the basis of the wrist morphology of A.
afarensis and other early hominins.

On the basis of their belief.
They correctly described some KWing features in anamensis & Lucy (also
described by Leakey in boisei).
But their interpretation is nonsense: there no evidence that the H/P LCA
ever KWed, to the contrary:
- KWing P & G is different, ontogenetically & anatomically (studies of
Inouye).
- Parallel evolution (to the same climatic changes) is to be expected in
strongly resembling spp.
- Not the slightest rudiment of KWing in Hs
http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Human_Evolution.html

Tuttle & Basmajian (1974) rejected
Washburn's original 'knuckle-walking' hypothesis on the grounds that
modern
human hands showed no evidence of a knuckle-walking ancestry.

Correctly.

I agree.

Both Dainton
(2001) and Lovejoy et al. (2001) have also questioned the modern revival
of
the hypothesis by offering different interpretations of the A. afarensis
wrist morphology.
A second current hypothesis for the ape-like locomotor behaviour
immediately antecedent to the evolution of bipedalism is the 'climbing
hypothesis' involving vertical climbing and orthograde clambering
behaviours, but no significant terrestrial locomotion (Fleagle et al.
1981).
Tuttle & Basmajian (1974) and Tuttle (1975, 1981) envisage this ancestor
as
a small-bodied climber and arboreal bipedal whereas others (e.g. Stern,
1975; Prost, 1980; Hunt, 1996) argue for a larger-bodied ancestor who
used
all four limbs to grasp supports during vertical climbing and suspension.
Most recently, Crompton and colleagues (Crompton et al. 2003; Thorpe &
Crompton, 2004) have argued on the basis of comparative bipedal
kinematics
that the antecedent locomotor type would have been more similar to
pronograde clambering as observed in modern orang-utans and unknown in
extant African apes."
(I don't understand this last sentence. I think that orang-utans
are orthograde.)

Yes, or even upside-down (suspensory = "anti-pronograde").
The hypothesis of vertical wading-climbing early hominids (H, P & G) is
likely IMO.

When you are climbing tree vertically, you CLINCH a tree trunk with
your legs (even cats can do it), to maintain grip. While doing that, you
squizze your legs, and put knees aside of a tree trunk. This is the very
thing you cannot do when you are climbing cliffs, so you MUST align your
legs, othervise your knees would bump into cliff.

As is usually the case, they are missing for just a little, but
for
just enough to completly miss the target. IOW, those top scientiests are
very close to my scenario. Also, your version of AAT is also very close
to
my scenario, and you are also missing for just a little, : ). There was
AAT,
only not in shallow, floaded waters, but on sea cliffs.
My scenario involves vertcal climbing of sea cliffs, plunge
diving
and swimming, and feeding on small tree fruits, plus downhill running. I
believe that all those things push in the direction of straight-body
bipedality, but the strongest factor is climbing of vertical surfaces,
where
you have the need to position the centre of mass of your body (ie., your
ass) right above your feet. -- Mario

Mario, no comparative data = no evidence.
There were no cliff-hanging hominids or so. --Marc

According to data and evidence, hominids didn't live ANY kind of
lifestyle.
There are few theories, and mine is one of them. It is in tune with
the avaible evidence. -- Mario

We are cliff-hangers.

Yes, and savanna-runners, Mario... :-D

For 200 million years we had rain forest. We never had a savanna
environment, before. 8Mya emerged savanna environment, with grass and all
its animals. Along with that emerged bipedals. Not before, and not after,
but right at that time. AFAIK, early bipedals are found in open
environment.

Extremely doubtful, Mario:
- Oreopith = swamp forest (bipedal?? parttime wading??)

Bipedal? No.

- Samburupith = part of maxilla IIRC (no evidence of bipedality)

Open environment. Thick enamel.

- Ouanopith // robust apiths (wetlands, some KWing features)

Hey Marc, wait a minute. Ouranopith is EXTREMELY open environment,
and extremely thick enamel. Robust Apiths came much later (Ouranopith at the
time just before the emergence of grass, and robust apiths A LOT MILLION
years later).

If some hominids-pongids (eg, robust apiths, Ouranopith, Gigantopith...)
lived in "savannas", it was in wetlands: parttime wading (probably bipedal
cf. lowland gorillas wading; rarely running & not impossibly on 4 legs
then).

Gee Marc, Ouranopithecus (the very first species which can, in some
dental ways, but dental is pretty much everything we have, be related to
bipedals) is found in EXTREMLY open environment. Even "impoverished",
environment, poor with plants. It was found in Greek-Iranian Province in
Vallesian time, the very place and time which was the first with open
ecology. And more, while EVERYWHERE in the whole world was still rain
forest, Ouranopithecus (the first which can be tied to bipedals) was found
at the very place where there WASN'T rain forest. Now, isn't that a strange?

But all this has nothing to with Homo: Ain-Hanech Algeria, Dmanisi
Georgia, Mojokerto Java... 1.8 Ma. --Marc

Of course. But Homo HAS something with that. -- Mario