Late Pliocene Homo and hominid land use from Western Olduvai Gorge,Tanzania

Excavation in the previously little-explored western portion of Olduvai Gorge indicates that hominid land use of the eastern paleobasin extended at least episodically to the west. Finds included a dentally complete Homo maxilla (OH 65) with lower face, Oldowan stone artifacts, and butchery-marked bones dated to be between 1.84 and 1.79 million years old. The hominid shows strong affinities to the KNM ER 1470 cranium from Kenya (Homo rudolfensis), a morphotype previously unrecognized at Olduvai. ER 1470 and OH 65 can be accommodated in the H. habilis holotype, casting doubt on H. rudolfensis as a biologically valid taxon.     

Lower Pliocene hominid remains from Sterkfontein

Cosmogenic aluminum-26 and beryllium-10 burial dates of low-lying fossiliferous breccia in the caves at Sterkfontein, South Africa, show that associated hominid fossils accumulated in the Lower Pliocene. These dates indicate that the skeleton StW 573 and newly discovered specimens from Jacovec Cavern have much the same age: approximately 4 million years. These specimens are thus of an age similar to Australopithecus anamensis from East Africa.     

Early hominid humerus from East Rudolf, Kenya

A fossil hominid humerus discovered in 1970 by the expedition to East Rudolf, Kenya, led by R. E. F. Leakey is examined in comparison with a large series of extant hominoids. This comparison as well as a multiple discriminant analysis shows the uniqueness of the fossil among the hominoids.     

Multivariate analysis of an early hominid metacarpal from swartkrans

Discriminant analysis permits hand bones of living primate genera to be represented as swarms of points in a multidimensional statistical framework within which intergroup relationships, and the affinities of fossil forms, can be examined. The metacarpal of Paranthropus from Swartkrans, South Africa, was so located with respect to groups of monkeys, apes, and modern man. The results suggest that the fossil metacarpal may be functionally similar to that of chimpanzees.     

Australopithecus garhi: a new species of early hominid from Ethiopia

The lack of an adequate hominid fossil record in eastern Africa between 2 and 3 million years ago (Ma) has hampered investigations of early hominid phylogeny. Discovery of 2.5 Ma hominid cranial and dental remains from the Hata beds of Ethiopia's Middle Awash allows recognition of a new species of Australopithecus. This species is descended from Australopithecus afarensis and is a candidate ancestor for early Homo. Contemporary postcranial remains feature a derived humanlike humeral/femoral ratio and an apelike upper arm-to-lower arm ratio.     

Evolutionary implications of pliocene hominid footprints

Hominid footprints discovered at the Pliocene (3.6 to 3.8 million years ago) site of Laetoli in northern Tanzania represent the earliest evidence of bipedalism in human evolution. This new evidence emphasizes the mosaic pattern of human evolution.     

U-Pb isotopic age of the StW 573 hominid from Sterkfontein, South Africa

Sterkfontein cave, South Africa, has yielded an australopith skeleton, StW 573, whose completeness has excited great interest in paleoanthropology. StW 573, or "Little Foot," was found 25 meters below the surface in the Silberberg Grotto. 238U-206Pb measurements on speleothems immediately above and below the fossil remains, corrected for initial 234U disequilibrium, yield ages of 2.17 +/- 0.17 million years ago (Ma) and 2.24(-0.07)(+0.09) Ma, respectively, indicating an age for StW 573 of close to 2.2 Ma. This age is in contrast to an age of approximately 3.3 Ma suggested by magnetochronology and ages of approximately 4 Ma based on 10Be and 26Al, but it is compatible with a faunal age range of 4 to 2 Ma.     

Early hominid population densities: new estimates

Proportional faunal representations in excavated fossil occurrences (Shungura Formation, Omo, Ethiopia) are very similar to modern sub-Saharan mammalian faunal proportions in a variety of environments. Early hominids comprise between 0.6 and 1.6 percent of the excavated assemblage, corrected to reflect numbers of individuals. With allochthonous faunal localities for comparison, direct analogies to modern fauna suggest early hominid population densities of between 0.006 to 1.7 individuals per square kilometer. Calculations based on population densities of modern large mammals indicate that population densities of early hominids were between 0.001 and 2.48 individuals per square kilometer.     

Late Miocene teeth from Middle Awash, Ethiopia, and early hominid dental evolution

Late Miocene fossil hominid teeth recovered from Ethiopia's Middle Awash are assigned to Ardipithecus kadabba. Their primitive morphology and wear pattern demonstrate that A. kadabba is distinct from Ardipithecus ramidus. These fossils suggest that the last common ancestor of apes and humans had a functionally honing canine-third premolar complex. Comparison with teeth of Sahelanthropus and Orrorin, the two other named late Miocene hominid genera, implies that these putative taxa are very similar to A. kadabba. It is therefore premature to posit extensive late Miocene hominid diversity on the basis of currently available samples.     

Linkage disequilibrium and recombination in hominid mitochondrial DNA

The assumption that human mitochondrial DNA is inherited from one parent only and therefore does not recombine is questionable. Linkage disequilibrium in human and chimpanzee mitochondrial DNA declines as a function of the distance between sites. This pattern can be attributed to one mechanism only: recombination.     

Primitive helium in diamonds

Thirteen diamond stones from various unspecified mines in South Africa were analyzed for the isotopic ratio of helium-3 to helium-4. Values of the ratio ranged from less than 10(-7) to (3.2 +/- 0.25) x 10(-4). The latter value is higher than the primordial helium-3/helium-4 ratio in meteorites and close to the ratio for solar-type helium. Such extremely high values may represent primitive helium that evolved very little (that is, showed very little increase in radiogenic helium-4) since the formation of the earth.