Op 12-07-2007 17:25, in artikel
1184253930.858436.159620@k79g2000hse.googlegroups.com, Lee
Olsen <paleocity@hotmail.com> schreef:
> On Jul 12, 4:37 am, Marc Verhaegen
> <m_verhae...@skynet.be> wrote:
>> Op 12-07-2007 12:27, in artikel
>> Aonli.20826$j7.378...@news.indigo.ie, Paul Crowley
>> <slkwuoiutiuytciu...@slkjlskjoioue.com> schreef:
>>
>>> "Rich Travsky" <traRvE...@hotmMOVEail.com> wrote in
>>> message news:4695C356.B76C3346@hotmMOVEail.com...
>>>> claudiusd...@sbcglobal.net wrote:
>>>>> Dr Haile-Selassie said the new dig sites yielded the
>>>>> bones of many monkeys, antelopes and wild pigs,
>>>>> suggesting that the hominids lived in a far greener and
>>>>> more wooded countryside than the bare stony Afar desert
>>>>> region seen today.
>>>> What, no oyster shells?
>>
>> Why??
>>
>> (This man is confusing apiths & Homo??)
>>
>>> The interesting feature about all these sites is their
>>> closeness to the (fossil) Sea of Afar. Bear in mind also
>>> that the whole region has been rising (as the result of
>>> geo- tectonic forces) over the past few million years. The
>>> sites would have been much closer to sea-level when they
>>> were occupied by hominids. Paul
>> Yes, not unlikely. Homo seems to appear in the Rift with
>> high sea levels: MH Trauth cs.2005 "Late Cenozoic Moisture
>> History of East Africa" Science
>> 309:2051-3: "3 humid periods at 2.72.5, 1.91.7 & 1.10.9
>> Ma ... could have had important impacts on the
>> speciation & dispersal of mammals & hominins"
> I like this post. Marc, the guy who thinks mountain beavers
> are semi- aquatic, is discussing the finer points of science
> with the guy who thinks chimps can't dig.
I like this post too, my little boy: it proves your stupidity:
just leave out the word "mountain beaver" & you get exactly
the same results: Australopithecine lifestyle - It has become
increasingly clear that most, if not all, hominids dwelt in
Œwet¹ rather than Œdry¹ habitats, and there is little doubt
that the early australopithecines of between four and three
million years ago dwelt in well-wooded and even forested
milieus such as swampy woodlands or streamside forests. For
example, Radosevich and co-workers, in a paper on
Australopithecus afarensis from Hadar, East Africa, said: ŒThe
bones were found in swale-like features ... it is very likely
that they died and partially rotted at or very near this site
... this group of hominids was buried in streamside gallery
woodland¹6. In addition, Rayner and co-workers wrote that the
A. africanus fossils of Makapansgat, South Africa, were found
in Œvery different conditions from those prevailing today.
Higher rainfall, fertile, alkaline soils and moderate relief
supported significant patches of sub-tropical forest and thick
bush, rather than savannah ... sub-tropical forest was the
hominins¹ preferred habitat rather than grassland or bushveld,
and the adaptation of these animals was therefore fitted to a
forest habitat¹7. Tobias, on the same species, recently wrote:
ŒFrom Sterkfontein, suggestions of greater woodland cover at
the time when Australopithecus was deposited in Member 4, had
emerged from studies on fossil pollen, but these were not
compelling. Then Wits team member Marian Bamford identified
fossil vines or lianas of Dichapetalum in the same Member
1184253931: such vines hang from forest trees and would not be
expected in open savannah. The team at Makapansgat
found floral and faunal evidence that the layers
containing Australopithecus reflected forest or
forest margin conditions. From Hadar, in Ethiopia,
where ŒLucy¹ was found, and from Aramis in
Ethiopia, where Tim White¹s team found
Ardipithecus ramidus, possibly the oldest hominid
ever discovered, well-wooded and even forested
conditions were inferred from the fauna
accompanying the hominid fossils. All the fossil
evidence adds up to the small-brained, bipedal
hominids of four to
1184253932.5 million years ago having lived in a woodland or
forest niche, not savannah¹5. The later robust
australopithecines of two to one million years ago,
lived in more open, though not treeless,
environments, apparently near riverbanks, lake
margins and reedbeds. For example, Kromdraai A.
robustus was found near grassveld and streamside or
marsh vegetation, in the vicinity of quail, pipits,
starlings and swallows, as well as parrots,
lovebirds and similar
psittacine birds19. Turkana A. aethiopicus was discovered in
Œoverbank deposits of a large perennial river¹, amid water-
and reedbucks20. Chesowanja A. boisei lay in a lagoon amid
exclusively aquatic species21. ŒAbundant root casts Š
suggest that the embayment was flanked by reeds and the
presence of calcareous algae indicates that the lagoon was
warm and shallow. Bellamya and catfish are animals tolerant
of relatively stagnant water Š¹21. This impression of marsh
vegetation the early australopithecines in more wooded and
the robusts in more open milieus is compatible with all
other information we have on australopithecines: postcranial
skeleton, masticatory and dentitional data, enamel
microwear, strontium/calcium ratios, and isotopic evidence.
Fossilized footprints and skeletal remains suggest that
australopithecines were bipedal, though their short-legged
style of bipedalism was different from that seen in
humans22, and apparently included a somewhat forward-leaning
trunk posture23. The StW 573 foot Œhad both bipedal and
climbing adaptations. This skeleton¹s foot morphology is
consistent with the bipedal Laetoli footprints, which are
not those of fully human feet, but which have very clear
ape-like morphology¹ xxx. Other tree-climbing features in
early australopithecines include the apelike upward directed
shoulder joints (glenoid fossae) and curved finger and toe
phalanges, whereas such features are less obvious in the
later robusts.
Dental studies suggest that whereas gracile australopithecines
preferred softer fruits and vegetables, the robusts¹ diet
included harder food items24-28,pp. Estimates of robust
australopithecine bite force suggest Œlow-energy food that had
to be processed in great quantities¹ and food objects Œhard
and round in shape¹29. DuBrul noticed striking dental
parallelisms between the robust australopithecines and the
bamboo-eating giant panda (broad, high and heavy cheekbones,
reduced prognathism and front teeth, very broad molar teeth,
premolar molarization), particularly when compared to gracile
australopithecines and non-panda bears respectively25.
Students of fossil hominid teeth agree that broad molars with
thick enamel and rounded cusps, while unsuitable for the
regular processing of tough foods like leaves or meat, are
suitable for the processing of hard food items. Papyrus and
reed were abundant in the paleo-environment of the later
australopithecines (e.g. Olduvai, Chesowanja, Kromdraai), and
Cyperaceae and Gramineae are part of the diet of living
African hominoidspp. Gorillas eat sedges and bamboo shoots and
stalks, all African hominids eat cane, chimpanzees and humans
eat water lilies, and rice and other cereals are staple food
for humans. Supplementing their diet with harder parts of
plants possibly helped the robusts to bridge the dry season,
when fruits and soft vegetables were scarcer.
Studies of dental enamel microwear provide further details. In
the early A. afarensis (Garusi-Laetoli and Hadar), the
cheekteeth enamel has a typical glossy polished surface and
the microwear has resemblances to that of capybaras and
mountain beavers30. These animals are semi-aquatic rodents
that feed mainly on succulent marsh and riverside herbs, as
well as grasses and the bark of young trees. It has recently
become clear that Western lowland gorillas spend some time
eating what researchers call AHV (aquatic herbaceous
vegetation) such as Hydrocharitaceae herbs and Cyperaceae
sedges3. Comparisons of molar enamel in South African fossils
show that A. robustus ate substantially more hard food items
than the earlier A. africanus31. Incisal microwear suggest
that A. robustus may have ingested foods that required less
extensive incisal preparation than the foods consumed by A.
africanus32, and incisal reduction in A. robustus also
suggests a less frugivorous diet, since Œincisors need not be
employed in the manipulation of hard objects¹33. The enamel of
the East African robusts (A. boisei of Olduvai and Peninj)
displays more pits, wide parallel striations and deep recessed
dentine27,pp. This microwear pattern has some resemblances
with that of beavers, which feed on riverine and riverside
herbs, the roots of water lilies, bark and woody plants. It
thus seems probable that an early australopithecine diet of
fruits (larger front teeth) and aquatic herbs (polishing) was
supplemented with woody plants in the robusts (more wear). The
suggestion of Walker, that
A. boisei KNM-ER 406 and 729 were bulk-eaters of Œsmall, hard
fruits with casings, pulp, seeds and all¹26, could explain
the deep recessed occlusal dentine, but not the glossy
appearance of the heavily polished enamel, which is more
typical of marsh plant feeders27,30. In terrestrial
grazers, tooth wear is very different34. In sheep, for
instance, the occlusal wear facets are not rounded. These
microwear data are consistent with the strontium/calcium
ratios35, as well as with the isotopic data of South
African australopithecines34. Apart from partial carnivory,
Sillen provides two possible explanations for the low Sr/Ca
ratios of A. robustus: eating leaves and shoots of forbs
and woody plants, and eating food derived from a wet
microhabitat, for instance, from well-drained streamside
soils35. Sillen as well as Sponheimer and Lee-Thorp,
following Œhunting hypotheses¹, prefer the regular
consumption of animal food as an explanation for the Sr/Ca
ratios and the isotopic data in A. robustus35,34, rather
than considering in our opinion the more logical
explanation that they might have eaten invertebrates as
well as cyperaceous sedges and other marshland plants.
Sponheimer and Lee-Thorp say that A. africanus Œate not
only fruits and leaves but also large quantities of
carbon-13-enriched foods such as grasses and sedges or
animals that ate these plants, or both¹34. Since
terrestrial grasses are incompatible with the polished,
rounded microwear30,34, and predominant meat-eating is
unlikely in view of the blunt, huge and broad
cheekteeth25,26,36, their diet more probably included
marshland plants such as Cyperaceae, as is indicated by
several very different studies27,30,34,35,pp. Several
independent lines of evidence paleo-milieu, postcranial
skeleton, dental morphology, enamel microwear, Sr/Ca
ratios, isotopic data suggest that some or all
australopithecines regularly waded bipedally in search of
plants growing in and near shallow waters. They might have
waded in much the same way as living hominid species such
as bonobos and Western gorillas do today (Figure 4), only
much more frequently2,3. This does not exclude the
possibility, however, that early hominids, including some
australopithecine species, might have processed and
consumed animal food when available37,38.