February 26, 2009

Early Humans Walked On Modern Feet

Ancient footprints discovered near Ileret in northern Kenya show that some of the earliest humans walked like us and did so on anatomically modern feet more than a million years ago, the Associated Press reported.

A Rutgers field school group of mostly American undergraduates excavated the site yielding the footprints, dated to between 1.51 million and 1.53 million years ago, researchers reported in the journal Science.

The researchers said the prints indicate a modern upright stride with a large toe parallel to the other toes. They are likely to have been made by the early hominid Homo ergaster or early Homo erectus "” the first hominids known to have had the same body proportions (longer legs and shorter arms) as modern Homo sapiens.

The rare impressions yielded information about soft tissue form and structure not normally accessible in fossilized bones. The Ileret footprints constitute the oldest evidence of an essentially modern human-like foot anatomy.

Ancient footprints found in Tanzania dating to 3.6 million years ago have been attributed to the less advanced Australopithecus afarensis. Those prints indicate an upright posture but with a shallower arch and a more ape-like, divergent big toe.

Lead author, Professor Matthew Bennett of Bournemouth University in the United Kingdom, scanned and digitized the Ileret footprints to ensure that comparisons made with modern human and other fossil hominid footprints were objective.

Emma Mbua of the National Museums of Kenya, said in a statement that the footprints are one of the most important discoveries of recent years, and the museum is doing everything possible to ensure the safety of such a unique site.

The authors reported that the upper sediment layer contained three footprint trails: two trails of two prints each, one of seven prints and a number of isolated prints. Five meters deeper, the other sediment surface preserved one trail of two prints and a single isolated smaller print, probably from a juvenile.

Others researchers who took part in the study include John W. K. Harris of Rutgers University and Brian G. Richmond of The George Washington University and the Smithsonian's National Museum of Natural History.


Image 2: In the foreground, Christine Galvagna, a Rutgers undergraduate at the time, meticulously cleans a trail of hominid footprints as Professor Harris (dark blue shirt) looks on. Credit: David Braun


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