New specimens and confirmation of an early age for Australopithecus anamensis

摘要: The discovery of Australopithecus anamensis fossils from strata lying between tephra dated at 4.17 and 4.12 million years ago, slightly higher not well constrained in age by overlying units, provoked the claim that more than one species might be represented: it was suggested stratigraphically fossils, which include important tibia, humerus a large, presumed male, mandible (KNM-KP 29287), belong to later, derived hominid. We have recovered new Kanapoi Allia Bay, Kenya, during field work 1995-1997 confirm primitive status anamensis, earliest Australopithecus. Isotope dating confirms A. anamensis' intermediate as being those Ardipithecus ramidus afarensis. New specimens maxilla, capitate show this is demonstrably A lower first deciduous molar (dm 1) morphology reported for Single-crystal 40Ar-39Ar determinations on Tuff that, except large mandible, all hominid are sediments deposited 4.17+/-0.03 4.07+/-0.02 ago.