Showing posts with label 2011.. Show all posts
Showing posts with label 2011.. Show all posts

Tuesday, July 26, 2011

Laetoli Footprints

The Laetoli footprints of Tanzania date back to approximately 3.5Ma. There are two sets of parallel prints that pressumably belong to Australopithecus afarensis due to their age. The prints were created when these hominids walked over freshly fallen ash from the Sadiman volcano. Due to its chemical composition, the next rainfall hardened the ash and preserved the footprints (Cowen, 2005). 

There has been much debate as to whether the prints indicate a hominid using a bent-knee, bent-hip biped walking posture like that used by chimpanzees or if they indicate a straight hind limb walking posture like that used by modern humans. Raichlen, Pontzer, and Sockol concluded in their kinesthetic study that either walking posture could have been utilized the by Laetoli hominids to create those particular track patterns (2008). 

Australopithecus ghari

Australopithecus ghari was found in Ethiopia and dates approximately 2.5Ma. Stone tools were found with A. ghari that date to the same time. Did A. ghari utilize tools?

Australopithecus robustus

Sometimes assigned to a separate genus, Pronthropus, Australopithecus robustus, is called so due to its features, particularly the larger, more powerful mandible and dentition. A. robustus lived approximately 2-1.3Ma. 

"Lucy"

The famous Lucy was nicknamed by Don Johanson who discovered her in Hadar, Ethiopia. Lucy is grouped among the gracile australopithecines, including A. afarensis, A. ghari, and A. anamensis, indicating a less robust and smaller framed skeletal structure. Australopithecus afarensis approximately 3.2Ma.