Fossil fossil of the juvenile hominid exhibiting features similar to those of monkeys

A rare juvenile fossil of our early hominid ancestor, Australopithecus afarensis has several foot features similar to those of monkeys that could have facilitated planting to climb trees, a new study finds. This conclusion challenges the long-standing hypothesis that A. afarensis was exclusively bipedal (using only two legs to walk) and only occasionally climbed into the trees . Juvenile hominid fossils provide unique insights into how traits (such as foot seizure) become less apparent when the individual grows up in adulthood. However, the juvenile specimens of most ancestors of human hominids are rare, and it was therefore difficult to trace the importance of traits chosen in animals over time. In 2002, archaeologists discovered a well-preserved partial skeleton of an infant A. afarensis that was thought to be about 3 years old at the time of death. Although this fossil from Dikika, Ethiopia, 3.32 million years old, was announced in a previous 2006 study, many skeletal elements, including the partial foot known as DIK-1 -1f, were buried in the sediments and therefore had to be carefully discovered. Many of these structures have now been exposed after additional preparatory work until 2013, and here, Jeremy M. DeSilva and his colleagues report the characteristics of this young hominin. They discovered that this baby possessed many of the structures needed to walk on two legs that were found in adult specimens, but it also retained a medial cuneiform convexity – an important bone for joint movement, like the one involved in the Climbing – in adulthood, they say. This evidence of the increased mobility of the toe is a model similar to that of the monkeys that DeSilva et al. to say is suggestive of a selective advantage of this trait and that offers new perspectives on the evolution of bipedalism.