Re: beach & brain (was Re: DHA ... savannah and bipedalism.

From: Marc Verhaegen (fa204466_at_skynet.be)
Date: 07/24/04 

Date: Sat, 24 Jul 2004 22:32:47 +0200

"Andrew Nowicki" <andrew@nospam.com> wrote in message
news:4102852C.37252E1@nospam.com...

> > I don't know when fire use evolved (earlier than 1.5 Ma?) & how
important it was, but it might well have been very important (for Homo, not
for apiths of course: enamel micro-wear suggests most apiths ate
predom.wetland plants).

> "Grasses have large quantities of silica crystals in their cells which
scratch tooth enamel. Browsing animals feed on the leaves, branches and
fruits of trees and bushes. These plant materials have fewer silica crystals
in their cells, and a more finely polished tooth surface results. Omnivorous
animals, eating meats as well as plant material, scratch their teeth heavily
when biting into bone."
http://www.yale.edu/ynhti/curriculum/units/1979/6/79.06.02.x.html

Yes.

> "Little is known about the diets of hominids that predate the Homo genus,
because these hominids did not leave archeological traces such as 'kitchen
middens' and stone tools. Consequently, researchers have made inferences
concerning hominid diet on the basis of craniodental morphology, gross
dental wear, and dental microwear. The current consensus is that the
3-million-year-old Australopithecus africanus hominid subsisted on fruits
and leaves, similar to the modern chimpanzee.

Overlapping diets, yes, likely.

> Early hominid diets are of some theoretical significance, since one
current view is that the emergence of the more intelligent Homo genus
depended on the consumption of high-quality animal foods that made possible
biological changes resulting in the evolution of a larger brain.

Yes, Homo = waterside food. Fr.Muskiet cs.2004 "Is Docosahexaenoic Acid
(DHA) Essential? Lessons from DHA Status Regulation, Our Ancient Diet,
Epidemiology and Randomized Controlled Trials" J.Nutr.134:183-6 "African
hominids have long been assumed to have been hunter-gatherers who obtained a
great deal of their food from the open savanna. Meat from savanna animals
is a poor DHA source, but savanna meat does have higher (n-3)/(n-6) ratios
compared with domestic animals. Savanna hunting is, however, not easy even
with modern tools. Hunting hominids at that stage of evolution would have
possessed unimaginable complex cognitive functions for planning, stalking,
coordinating and communication. It is more likely that they lived at the
margins of lakes and rivers or at the seashore, because that is where most
of their remains and tools have been discovered. ... "We may have to trade
the picture of our Afr.ancestors from a brawny hunter who brings home the
wildebeest to butcher it with stone tools into that of a fisherman who wades
the placid lakes and comes home with easily caught fish, seabird eggs,
mollusks and other marine foods". Many fishes from tropical warm waters
incl.those in lakes Nyasa and Turkana, are rich sources of AA and DHA, as
opposed to their EPA- and DHA-rich counterparts from the more northern
climates. ..." (If you're interested, I have the PDF, I believe).

> M.Sponheimer and J.A.Lee-Thorp (1999) now report a stable carbon isotope
analysis of A.africanus fossils from Makapansgat Limeworks, South Africa.
The authors sampled 4 of the 14 Australopithecus africanus individuals that
have been unearthed at that location, and also analyzed the dental enamel of
associated 3-million year old animals (65 individual animals from 19
mammalian taxa) in order to place A. africanus within a broader ecological
context. The authors report their results demonstrate that A.africanus ate
not only fruits and leaves, but they also ate large quantities of carbon-13
enriched foods such as grasses and sedges, or they ate animals that ate
these plants, or both. The authors suggest their results indicate that early
hominids such as A.africanus regularly exploited relatively open
environments such as woodlands or grasslands for food, and that early
hominids may have consumed high-quality animal foods before the development
of stone tools and the origin of the genus Homo. (Science Week April 1999)"
http://cogweb.ucla.edu/ep/Paleoanthropology.html
http://aeroman.de/html/paleoanthropology.html

Yes. When you omit the interpretations & keep the facts, you have: "fruits &
leaves & grasses & sedges & animals that ate these plants". Since their
dentition is the opposite of carnivores (carnassial teeth, large canines
etc.), you only keep "fruits & leaves & grasses & sedges". Since grasses
leave different micro-wear (fabric-like wear etc.), you only keep "fruits &
leaves & sedges". Since leaves require sharp ridges to slice (tough) leaves
(the opposite of apiths), you only keep "fruits & sedges"... :-) This is
exactly what all other other sources of information also suggest: waterside
plants & probably fruits & nuts & possibly some animal food.

> "Marc Verhaegen & Stephen Munro - 23 July 1999 (excerpt) Sponheimer &
Lee-Thorp (1999) say that A.africanus "ate 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 both". Since terrestrial grasses are
incompatible with the polished microwear (e.g. Sponheimer & Lee-Thorp 1999,
Puech et al. 1986), and regular meat-eating is incompatible with the small
front teeth and the huge and broad cheekteeth (e.g. Wood & Aiello 1998,
DuBrul 1977, Walker 1981), their diet more probably included marshland
plants such as Cyperaceae, as is shown by the very different studies by
Puech (1992), Sillen (1992) and Sponheimer & Lee-Thorp (1999)."
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html

:-) Nothing to add, except that the diet of E. & S.Afr.apiths might have
differed a bit (S.Africans more omni-, E.Africans more herbivory?), and that
gracile ("Australop") & robust apith ("Paranthr", see Teaford-Ungar below)
diets also differed (eg, more woody parts in robust diet).

> Teaford & Ungar 2000 "Diet and the evolution of the earliest human
ancestors" PNAS 97:13506-11 As for the early hominids, A.africanus had more
occlusal relief than did Paranthropus robustus, suggesting a dietary
difference between these species (30). Additional preliminary shearing
quotient studies support this idea while reaffirming that the
australopithecines, as a group, had relatively flat, blunt molar teeth and
lacked the long shearing crests seen in some extant hominoids (28). By
itself, this indicates that the earliest hominids would have had difficulty
breaking down tough, pliant foods, such as soft seed coats and the veins and
stems of leaves, although they probably were capable of processing buds,
flowers, and shoots. Interestingly, as suggested by Lucas and Peters (46),
another tough pliant food they would have had difficulty processing is meat.
In other words, the early hominids were not dentally preadapted to eat meat,
they simply did not have the sharp, reciprocally concave shearing blades
necessary to retain and cut such foods. In contrast, given their flat, blunt
teeth, they were admirably equipped to process hard brittle objects. What
about soft fruits? It really depends on the toughness of those fruits. If
they were tough, then they would also need to be precisely retained and
sliced between the teeth. Again, early hominids would be very inefficient at
it. If they were not tough, then the hominids could certainly process soft
fruits."
http://www.cast.uark.edu/local/icaes/conferences/wburg/posters/pungar/satalk.htm
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=17605
"A.afarensis were eating fibrous material. This type of tooth wear is
indicative stripping leaves. Broken enamel also indicates that they were
eating hard foods such as nuts as well. Microwear on anterior teeth in the
form of microstriations suggests they were using their front teeth to strip
vegetation." http://anthroclass.com/lectures/anlec/class12.html

Yes. What did they strip? I guess mostly parts of reeds & cyper & possibly
bamboo, as the microwear & the paleo-environment suggest. No doubt they had
a very varied diet. IIRC chimps eat more than 100 different plant spp.

> The majority view is that A.afarensis inhabited a mosaic environment, a
mixture of dry bushland, riparian woodland, probably with seasonal
floodplains, and riverine forest habitats. A.africanus lived in dry
woodland, with grassland beyond.

Grassland beyond, yes. But dry?? No, no: gracile apiths in waterside
forests, robust apiths in more open wetlands:
§ Kanapoi KNM-KP 29281 Australopithecus anamensis: Fish, aquatic
reptiles, kudus and monkeys are prevalent. 'A wide gallery forest would have
almost certainly been present on the large river that brought in the
sediments' (Leakey et al., 1995).

§ Chad KT 12 A. cf. afarensis: 'The non-hominid fauna contains
aquatic taxa (such as Siluridae, Trionyx, cf. Tomistoma), taxa adapted to
wooded habitats (such as Loxodonta, Kobus, Kolpochoerus) and to more open
areas (such as Ceratotherium, Hipparion) [.] compatible with a lakeside
environment' (Brunet et al., 1995).

§ Garusi-Laetoli L.H. A. anamensis or afarensis: Teeth and mandible
fragments, the hardest skeletal parts which are frequently left over by
carnivores (Morden, 1988), come from wind-blown and air-fall tuffs (Leakey
et al., 1976). Cercopithecine and colobine monkeys are present (Protsch,
1981; Leakey et al., 1976).

§ Hadar, Afar Locality: 'Generally, the sediments represent
lacustrine, lake margin, and associated fluvial deposits related to an
extensive lake that periodically filled the entire basin' (Johanson et al.,
1982)

§ Hadar AL.333 A. afarensis: 'The 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 woodland' (Radosevich et al., 1992).

§ Hadar AL.288 gracile A. afarensis: Lucy lay in a small, slow
moving stream. 'Fossil preservation at this locality is excellent, remains
of delicate items such as crocodile and turtle eggs and crab claws being
found' (Johanson & Taieb, 1976).

§ Makapan A. africanus: '[.] very 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. Taphonomic considerations [.] suggest that
sub-tropical forest was the hominins' preferred habitat rather than
grassland or bushveld, and the adaptations of these animals was therefore
fitted to a forest habitat' (Rayner et al., 1993; see also Reed, 1993; and
Wood, 1993).

§ Taung australopithecine: 'the clayey matrix from which the Taung
cranium was extracted, and the frequent occurrence of calcite veins and void
fillings within it (Butzer, 1974, 1980) do suggest a more humid environment
during its accumulation' (Partridge, 1985).

§ Sterkfontein A. africanus and Swartkrans A. robustus: Many South
African australopithecines are discovered in riverside caves, presumably
often filled with the remainders of the consumption process of large felids
(Brain, 1981).

§ Kromdraai: A. robustus was found near grassveld and streamside or
marsh vegetation, in the vicinity of quail, pipits, starlings, swallows, and
parrots, lovebirds and similar psittacine birds (T. N. Po*** in Brain,
1981).

§ Turkana KNM-ER 17000 and 16005: A. aethiopicus was discovered near
the boundary between overbank deposits of large perennial river and alluvial
fan deposits, amid water- and reedbucks (Walker et al., 1986).

§ Lake Turkana: 'The lake margins were generally swampy, with
extensive areas of mudflats [.] Australopithecus boisei was more abundant in
fluvial environments, whereas Homo habilis was rare in such environments [.]
Australopithecus fossils are more common than Homo both in channel and
floodplain deposits. The gracile hominids [.] seem to be more restricted
ecologically to the lake margin than are the robust forms' (Conroy, 1990).

§ Ileret A. boisei: 'the fossil sample reflects climatic and
ecological environmental conditions differing significantly from those of
the present day. At Ileret, 1.5 Myr ago, climatic conditions must have been
cooler and more humid than today, and more favourable to extensive forests
[.] The prominence of montane forest is particularly striking [.] dominated
by Gramineae and Chenopodiaceae appropriate to the margins of a slightly
saline or alkaline lake' (Bonnefille, 1976).

§ Konso A. boisei: 'The highly fossiliferous sands at the
mid-section of KGA10 are interpreted to be the middle to distal portions of
an alluvial fan, deposited adjacent to, and extending into, a lake. Fossils
and artefacts deriving from horizons of sands and silts are not abraded and
show evidence of minimal transport. A large mammalian assemblage has been
collected from the deposits, showing a striking dominance of Alcelaphini [.]
to indicate the presence of extensive dry grasslands at KGA10' (Suwa et al.,
1997).

§ Chesowanja A. boisei: 'The fossiliferous sediments were deposited
in a lagoon [.] Abundant root casts [.] 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, and such situation would also be suitable for
turtles and crocodiles' (Carney et al., 1971).

§ Olduvai middle Bed I: A. boisei O.H.5 as well as habilis O.H.7 and
O.H.62 were found in the most densely vegetated, wettest condition, with the
highest lake levels (Walter et al., 1991), near ostracods, freshwater
snails, fish, and aquatic birds (Conroy, 1990); '[.] the middle Bed-I faunas
indicate a very rich closed woodland environment, richer than any part of
the present-day savanna biome in Africa [.]' (Fernández-Jalvo et al., 1998).
'Fossilized leaves and pollen are rare in the sediments of Beds I and II,
but swamp vegetation is indicated by abundant vertical roots channels and
casts possibly made by some kind of reed. Fossil rhizomes of papyrus also
suggest the presence of marshland and/or shallow water' (Conroy, 1990). '[.]
Cyperaceae fruits were common in H.habilis habitat (Bonnefille, 1984).
Ancient Egyptians ate Cyperus papyrus root which was also present at Olduvai
in swamp-margins and river banks' (Puech, 1992).

____________________________________________________________

> My comment: A.afarensis may have eaten buds, flowers, and shoots of marsh
plants,

Yes.

> but A.africanus did not.

?? Ah?

> A.africanus ate meat

Not totally impossible (cf. hunting chimps), but not the slightest direct
evidence.

> but its teeth do not look like teeth of an animal which ate raw meat.

Indeed.

> Homo have smaller masticatory apparatus than Apiths. This may be explained
as Apiths eating smaller, fried animals (snakes, lizards, and insects) along
with their bones. It would take too much time to remove the bones and skin,
so the Apiths ate these small animals whole.

The masticatory reduction in Homo is incompatible with more hunting or
scavenging, although it's likely they butchered animals drown at annual
treks etc. (no doubt they had learnt to process turtles & stranded whales
etc. at the coasts, after they had learnt to use stone to open oysters
etc.). The only explanations for the remarkable reduction in dentition,
cheek bones & masticatory musculature (MYH16 gene) in Homo is fire use or
(more likely = fitting with all other evidence) suction feeding (eg,
seafood).

> I am not a professional paleontologist, so I may be wrong,

:-D That's no problem; Andrew: many prof PAs (except Puech, Ungar etc.)
are obviously completely wrong.

Marc Verhaegen
http://www.onelist.com/community/AAT
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html