Oldest evidence of tool making hominins in a grassland-dominated ecosystem.
BACKGROUND
Major biological and cultural innovations in late Pliocene hominin evolution are frequently linked to the spread or fluctuating presence of C(4) grass in African ecosystems. Whereas the deep sea record of global climatic change provides indirect evidence for an increase in C(4) vegetation with a shift towards a cooler, drier and more variable global climatic regime beginning approximately 3 million years ago (Ma), evidence for grassland-dominated ecosystems in continental Africa and hominin activities within such ecosystems have been lacking.


RESULTS
We report stable isotopic analyses of pedogenic carbonates and ungulate enamel, as well as faunal data from approximately 2.0 Ma archeological occurrences at Kanjera South, Kenya. These document repeated hominin activities within a grassland-dominated ecosystem.


CONCLUSIONS
These data demonstrate what hitherto had been speculated based on indirect evidence: that grassland-dominated ecosystems did in fact exist during the Plio-Pleistocene, and that early Homo was active in open settings. Comparison with other Oldowan occurrences indicates that by 2.0 Ma hominins, almost certainly of the genus Homo, used a broad spectrum of habitats in East Africa, from open grassland to riparian forest. This strongly contrasts with the habitat usage of Australopithecus, and may signal an important shift in hominin landscape usage.
Department of Anthropology, Queens College and NYCEP, Flushing, New York, USA. thomas.plummer@qc.cuny.edu
Thomas W
TW
Plummer
Peter W
PW
Ditchfield
Laura C
LC
Bishop
John D
JD
Kingston
Joseph V
JV
Ferraro
David R
DR
Braun
Fritz
F
Hertel
Richard
R
Potts
D000818:Animals; D005075:Biological Evolution; D002244:Carbon; D002980:Climate; D017753:Ecosystem; D005580:Fossils; D005843:Geography; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D010163:Paleontology; D006109:Poaceae / Q000235:genetics
D002244:Carbon