Natural Science Forum / Biology / Paleontology / May 2007

Op 22-05-2007 03:30, in artikel eIr4i.100$%T3.26@bignews8.bellsouth.net,
George <george@yourservice.com> schreef:

There is no conclusive paleo-ecol.evidence (but certainjly no
paleo-ecol.contra-evidence): AAT is mostly based on comparative data.

"waded in shallow waters":
- Primates wade biepdally = (partial) origin of human bipedality?
- Sahelanthr, Orrorin, apiths are all found in wetlands, at first more
wooded wetland, later (robust apiths) more open wetlands.
- Ndoki gorillas wade a lot in shallow wqater, eating aquatic herbaceous
herbs.

"in forest clearings, gallery forests or mangrove areas":
- All early hominids are found in well-watered & well-wooded milieus.
- The example of Ndoki gorillas.
- Trees (climbing arms overhead) were necessary to explain the curved
phalanges, the gorilla like scapula, the upward oriented glenoid fossa etc.

"in search for floating fruit":
- Hypothetical (all apes eat fruits): fruits leave no microwear traces.

"segdes, reeds, AHV":
- Isotopic data suggest sedge-eating (Sponheimer...).
- Paleo-ecol.data: many robusts are found amid reeds.
- Dentitional arguments: broad cheekteeth...: calorie-poor diet.
- Microwear data: afarensis enamel is polished by wet plants (Puech).

"fish &/or shellfish":
- Poly-unsat.fatty acids = healthy for humans.
- Easy to find, collect & digest.
- Explains stone tool use (cf.sea otters, capuchins opening mangrove
oysters...).
- Human (slow-)diving skills.

Some data on paleo-ecol.sites:
(Stephen Munro has a much more complete list.  We have a paper on this in
press.  I'll let sci.bio.pal know.)
§      Orrorin Lukeino KNM-LU 335: ŒThe red beds seems to contain marginal
lacustrine deposits as indicated by the presence of algal mats and
lacustrine bivalves (including complete specimens with valves in the closed
position)¹ (Pickford, 1975).
§      Tabarin KNM-TH 13150 ³pre-australopithecine²: ŒThe fauna includes
aquatic animals such as molluscs, fish, turtles, crocodiles, and hippotami,
along with others that might be found in the vicinity of a lake of river¹
(Ward & Hill, 1987).
§      Ardipithecus ramidus: ŒSedimentological, botanical and faunal
evidence suggests a wooded habitat for the Aramis hominids [Š] Aquatic
elements (turtle, fish, crocodile) are rare. Large mammals (hippopotamus,
proboscideans, rhinos, equids, giraffids, bovines) are rare. Primates are
very abundant¹ (WoldeGabriel et al., 1994); Œ[Š] interpreted to have been a
closed woodland. At Aramis, aquatic species and large mammals are rare, and
colobines make up over 30% of all vertebrate specimens collected¹ (Leakey et
al., 1995).
§      Kanapoi KNM-KP 29281 Australopithecus anamensis: Fish, aquatic
reptiles, kudus and monkeys are prevalent. ŒA wide gallery forest would have
almost certainly been present on the large river that brought in the
sediments¹ (Leakey et al., 1995).
§      Chad KT 12 A. cf. afarensis: ŒThe 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) [Š] compatible with a lakeside
environment¹ (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).  Colobines & pythons.
§      Hadar, Afar Locality: ŒGenerally, the sediments represent lacustrine,
lake margin, and associated fluvial deposits related to an extensive lake
that periodically filled the entire basin¹ (Johanson et al., 1982)
§      Hadar AL.333 A. afarensis: ŒThe bones were found in swale-like
features [Š] it is very likely that they died and partially rotted at or
very near this site [Š] this group of hominids was buried in streamside
gallery woodland¹ (Radosevich et al., 1992).
§      Hadar AL.288 gracile A. afarensis: Lucy lay in a small, slow moving
stream. ŒFossil preservation at this locality is excellent, remains of
delicate items such as crocodile and turtle eggs and crab claws being found¹
(Johanson & Taieb, 1976).
§      Makapan A. africanus: Œ[Š] 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 [Š] suggest that
sub-tropical forest was the hominins¹ preferred habitat rather than
grassland or bushveld, and the adaptations of these animals was therefore
fitted to a forest habitat¹ (Rayner et al., 1993; see also Reed, 1993; and
Wood, 1993).
§      Taung australopithecine: Œthe 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 accumulation¹ (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. Pocock 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: ŒThe lake margins were generally swampy, with extensive
areas of mudflats [Š] Australopithecus boisei was more abundant in fluvial
environments, whereas Homo habilis was rare in such environments [Š]
Australopithecus fossils are more common than Homo both in channel and
floodplain deposits. The gracile hominids [Š] seem to be more restricted
ecologically to the lake margin than are the robust forms¹ (Conroy, 1990).
§      Ileret A. boisei: Œthe 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 [Š] The
prominence of montane forest is particularly striking [Š] dominated by
Gramineae and Chenopodiaceae appropriate to the margins of a slightly saline
or alkaline lake¹ (Bonnefille, 1976).
§      Konso A. boisei: ŒThe 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 [Š]
to indicate the presence of extensive dry grasslands at KGA10¹ (Suwa et al.,
1997).
§      Chesowanja A. boisei: ŒThe fossiliferous sediments were deposited in
a lagoon [Š] Abundant 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, and such situation would also be suitable for turtles and
crocodiles¹ (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); Œ[Š] the middle Bed-I faunas
indicate a very rich closed woodland environment, richer than any part of
the present-day savanna biome in Africa [Š]¹ (Fernández-Jalvo et al., 1998).
ŒFossilized 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 water¹ (Conroy, 1990). Œ[Š]
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 banks¹ (Puech, 1992).
§      Olduvai O.H.24 habilis: ŒCrocodile remains predominate among the
faunal material from this site and more than 2,000 teeth were found.
Tortoise plates, shells of Urocyclid slugs, fish vertebrae and scales, bird
bones and pieces of ostrich eggshell were also relatively common (Leakey et
al., 1971).
§      Malawi UR 501 early Homo: ŒThe Plio-Pleistocene Chiwondo Beds of
Northern Malawi have yielded molluscs and fragmented remains of fish,
turtles, crocodiles and large mammals [Š] Microvertebrates and carnivores
are virtually unrepresented in the assemblage [Š] The general ecological
setting of the Malawi Rift during the Late Pliocene was a mosaic environment
including open and closed, dry and wet habitats, and which harbored a small
and ecologically unstable paleolake Malawi¹ (Schrenk et al., 1995).
§      Chemeron KNM-BC1 early Homo: ŒThe Fish Beds [Š] seem to be almost
entirely lacustrine and fluviatile; fish remains are abundant [Š] Molluscs
also lived in the lake, and locally their remains accumulate to form shelly
limestones¹ (Martyn & Tobias, 1967).
§      Turkana Boy KNM-WT 15000 H. erectus: ŒMammalian fossils are rare at
this locality, the most abundant vertebrate fossils being parts of small and
large fish. The depositional environment was evidently an alluvial plain of
low relief [Š] Typical lacustrine forms (for example, ostracods, molluscs)
could invade the area [Š] The only other fauna found so far in the
fossiliferous bed are many opercula of the swamp snail Pila, a few bones of
the catfish Synodontis and two fragments of indeterminate large mammal bone
[Š]¹ (Brown et al., 1985).
§      Mojokerto H. erectus: ŒThe basal part of the Putjangan Beds is
composed of volcanic breccias containing marine and freshwater molluscs. The
rest of the Putjangan Beds is composed of black clays of lacustrine origin¹
(Ninkovich & Burckle, 1978).
§      Peking H. erectus: ŒA big river and possibly a lake were located to
the east and contained various water species; along the shorelines grew
reeds and plants, which were home for buffalo, deer, otters, beavers and
other animals¹ (Poirier, 1978); Œ[Š] accumulation in quiet water. The cave
at this time was probably the locus of ponded water and was probably more
open to the atmosphere¹ (Weiner et al., 1998).
§      Hopefield, Rabat & Terra Amata: H. erectus fossils came from
sandstone made up from dune sand resting upon a former sea beach (De Lumley,
1990). In Terra Amata, Œthere are also indications that the inhabitants ate
oysters, mussels and limpets ­ shells of which are present. The presence of
fish bones and fish vertebrae indicate that the population also fished¹
(Poirier, 1987).
Etc.Etc.

Schematically:
- early hominids: water+trees
- gracile apiths: water+trees
- robust apiths: more open wetlands
- Homo: near shellfish

--Marc