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New specimens and confirmation of an early age for Australopithecus anamensis

Nature volume 393, pages 6266 (07 May 1998) | Download Citation

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Abstract

The discovery of Australopithecus anamensis fossils1 from strata lying between tephra dated at 4.17 and 4.12 million years ago, and from slightly higher strata not well constrained in age by overlying dated units, provoked the claim that more than one species might be represented: it was suggested that the stratigraphically higher fossils, which include the important tibia, humerus and a large, presumed male, mandible (KNM-KP 29287), might belong to a later, more derived hominid2. We have recovered new fossils from Kanapoi and Allia Bay, Kenya, during field work in 1995–1997 that confirm the primitive status of Australopithecus anamensis, the earliest species of Australopithecus. Isotope dating confirms A.anamensis' intermediate age as being between those of Ardipithecus ramidus3,4 and Australopithecus afarensis5,6. New specimens of maxilla, mandible and capitate show that this species is demonstrably more primitive than A. afarensis. A lower first deciduous molar (dm1) is intermediate in morphology between that reported for Ardipithecus ramidus4 and A.afarensis7. Single-crystal 40Ar–39Ar age determinations on the Kanapoi Tuff show that, except for a large mandible, all of the hominid fossils from Kanapoi are from sediments deposited between 4.17 ± 0.03 and 4.07 ± 0.02 million years ago.

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References

  1. 1.

    , , & New four million-year-old hominid species from Kanapoi and Allia Bay, Kenya. Nature 376, 565–571 (1995).

  2. 2.

    Paleontology—Ecological apes and ancestors. Nature 376, 555–556 (1995).

  3. 3.

    , & Australopithecus ramidus, a new species of early hominid from Aramis, Ethiopia. Nature 371, 306–312 (1994).

  4. 4.

    , & Corrigendum: Australopithecus ramidus, a new species of early hominid from Aramis, Ethiopia. Nature 375, 88 (1995).

  5. 5.

    & Asystematic assessment of early African hominids. Science 202, 321–330 (1979).

  6. 6.

    , & The first skull and other new discoveries of Australopithecus afarensis at Hadar, Ethiopia. Nature 368, 449–451 (1994).

  7. 7.

    , & Dental remains from the Hadar Formation, Ethiopia: 1974–1977 collections. Am. J. phys. Anthrop. 57.545–603 (1982).

  8. 8.

    & Stratigraphy, depositional environments and palaeogeography of the Koobi Fora Formation.in Koobi Fora Research Project Vol. 3(ed. Harris, J. M.) 1–30 (Clarendon, Oxford, (1991).

  9. 9.

    Geology of Miocene Sediments of the Lower Kerio Valley, Kenya(Thesis, Univ. Princeton, (1980).

  10. 10.

    Geochemistry, Geochronology and Tephrostratigraphy of Tephra from the Turkana Basin, Southern Ethiopia and Northern Kenya(Thesis, Univ. Utah, (1995).

  11. 11.

    , , & Hominid carpal, metacarpal, and phalangeal bones recovered from the Hadar Formation: 1974–1977 collections. Am. J. phys. Anthrop. 57, 651–677 (1982).

  12. 12.

    Early Hominid Posture and Locomotion(University of Chicago Press, Chicago, (1972).

  13. 13.

    Unusual unity. Nat. Hist. 106, 20–23 and 69–70 (1997).

  14. 14.

    et al. The Fish Canyon Tuff, a potential standard for the 40Ar/39Ar and fission track dating methods.(Abstract) Terra Cognita 6, 139–140 (1986).

  15. 15.

    & Geochronology and Thermochronology by the 40Ar/39Ar Method(Oxford Univ. Press, New York, (1988).

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Acknowledgements

We thank the Government of Kenya for permission to carry out this research and the National Museum of Kenya for logistical support. The National Geographic Society funded the field work; the National Science Foundation and the Leakey Foundation awarded grants to C.F. and A.W. Neutron irradiations were facilitated by the Australian Institute of Nuclear Science and Engineering and the Australian Nuclear Science and Technology Organization. We thank Caltex (Kenya) for fuel and Rover Group and the NGS for vehicles, and T. White and F. Spoor for their help. The expedition included K.Cheboi, S. Dominic, G. Ekalale, M. Eregae, J. Erus, N. Ewalan, J. Kaatho, C. Kiarie, K. Kimeu, F. Kyalo, M. Kyeva, B. Kyongo, L. Leakey, N. Lowis, S. Makathimo, B. Malika, W. Mangao, S. Milledge, L. Moru, M.Muoka, J. Mutaba, D. Mutinda, N. Mutiwa, S. Ngui, B. Onyango and J. Wynn; S. Hagemann and L.Hlusko assisted at Allia Bay; J. Mya undertook the mineral separations; R. Maier assisted with handling of samples for irradiation; and A. Ibui, F. Kyalo, E. Mbua, M. Muungu and A. Mwai provided curatorial assistance.

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Affiliations

  1. *National Museums of Kenya, PO Box 40658, Nairobi, Kenya

    • Meave G. Leakey
  2. †Department of Anthropology, Rutgers University, New Brunswick, New Jersey 08901, USA

    • Craig S. Feibel
  3. ‡Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia

    • Ian McDougall
  4. §Departments of Anthropology and Pathology & Anatomical Sciences, University of Missouri, Columbia, Missouri 65211, USA

    • Carol Ward
  5. Departments of Anthropology and Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • Alan Walker

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Correspondence to Meave G. Leakey.

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https://doi.org/10.1038/29972

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