Access

Letters to Nature

Nature 404, 382-385 (23 March 2000) | doi:10.1038/35006045; Received 10 August 1999; Accepted 10 January 2000

Open Innovation Challenges

naturejobs

Evidence that humans evolved from a knuckle-walking ancestor

Brian G. Richmond & David S. Strait

  1. Department of Anthropology, The George Washington University, 2110 G Street, NW, Washington, DC 20052, USA

Correspondence to: Brian G. Richmond Correspondence and requests for materials should be addressed to B.G.R. (e-mail: Email: brich@gwu.edu)

Top

Bipedalism has traditionally been regarded as the fundamental adaptation that sets hominids apart from other primates. Fossil evidence demonstrates that by 4.1 million years ago1, and perhaps earlier2, hominids exhibited adaptations to bipedal walking. At present, however, the fossil record offers little information about the origin of bipedalism, and despite nearly a century of research on existing fossils and comparative anatomy, there is still no consensus concerning the mode of locomotion that preceded bipedalism3, 4, 5, 6, 7, 8, 9, 10. Here we present evidence that fossils attributed to Australopithecus anamensis (KNM-ER 20419)11 and A. afarensis (AL 288-1)12 retain specialized wrist morphology associated with knuckle-walking. This distal radial morphology differs from that of later hominids and non-knuckle-walking anthropoid primates, suggesting that knuckle-walking is a derived feature of the African ape and human clade. This removes key morphological evidence for a Pan–Gorilla clade, and suggests that bipedal hominids evolved from a knuckle-walking ancestor that was already partly terrestrial.

  1. Department of Anthropology, The George Washington University, 2110 G Street, NW, Washington, DC 20052, USA

Correspondence to: Brian G. Richmond Correspondence and requests for materials should be addressed to B.G.R. (e-mail: Email: brich@gwu.edu)