February 26th, 2009 in Breaking News

Modern Feet Step Back 1.5 Million Years

Science News / Modern Feet Step Back 1.5 Million Years.

Human ancestors created some remarkably lasting impressions on the eastern African landscape around 1.5 million years ago. Walking across a muddy patch of terrain near what’s now Ileret, Kenya, these ancient individuals left footprints that hardened and have now been excavated by a team of scientists.

On close inspection, the preserved footprints provide the oldest evidence for a virtually modern-human foot and walking style in a human ancestor, report geologist Matthew Bennett of Bournemouth University in Poole, England, and his colleagues in the Feb. 27 Science. Finding what amounts to the fossilized behavior of these creatures provides new clues to the evolution of upright stance and walking in modern humans.

Bennett’s team identifies the ancestor as an early Africa-based Homo erectus, or Homo ergaster as some scientists call it.

Measures of the size, spacing and depth of the Ileret impressions allowed the researchers to estimate individuals’ heights, weights and stride lengths, all of which fell within the range of modern humans. Digitized images of the newly discovered footprints show a big toe in line with the other toes, an arrangement that contrasts with the angled, grasping big toes of apes. Other humanlike features of the prints include a pronounced arch and short toes.

Ancient foot impressions at Ileret complement earlier fossil leg and pelvis finds in Africa indicating that, by about 2 million years ago, early H. erectus displayed much the same body size and proportions as modern humans, the researchers say.