The end Lucy’s life can be a starting point for the evolutionary history of humans. A new fossil analysis discovered in 1974 in Afar in northern Ethiopia, allowed to give a unique explanation for the final moments of Australopithecus afarensis , who lived 3.18 million years. Lucy will have fallen from a tree, broke several bones, suffered internal injuries and died, according to an article published on Monday in the edition online magazine Nature .
the fall may be related to the hybrid capabilities Lucy’s locomotion, whose skeleton had some features associated with bipedalism, making it one of the most interesting fossils from the study of human evolution.
“it is ironic that the fossil, which is at the center of the debate on the importance of arboreal environment in human evolution, has probably died from injuries sustained during the fall of a tree,” says John Kappelman, a paleoanthropologist at the University of Texas at Austin ( USA), leader of the study, said in a statement that institution.
the fossil of Lucy was discovered on 24 November 1974 by the famous American paleoanthropologist Donald Johnson, the archaeological site of Hadar. The skeleton was of an adult female with little more than a meter tall and contained some skull fragments, the lower jaw (mandible), part of the vertebrae and ribs, most of the bones of the two arms of the bowl and some fragments of leg bones.
About 40% of the skeleton survived until today. At the time, it was one of the most complete fossils of a pre-human hominid. Ie before the gender Homo , which have emerged less than 2.8 million years. So it is not surprising happiness of the team.
“On the night of 24 November, there was much enthusiasm and celebrated the discovery of what appeared to be a skeleton of a fairly complete hominid,” describes If an article of questions and answers about this fossil in the site of the Institute of Human Origins at Arizona State University in the United States. Among a lot of information, the article explains the name given to Australopithecus. “There were drinks, dancing and singing. The Beatles song Lucy in the Sky with Diamonds was happening repeatedly. Sometime that night, no one remembers when or by whom, the skeleton was dubbed Lucy . The name stuck. “
At the crossroads of human evolution
The explanation of how human evolution happened in the last six million years, is dependent on fossil and remains as the Lucy. Africa is central to this investigation. It was on this continent that first emerged gender Homo , and later, our species, the Homo sapiens .
Among the prehuman hominids, as the Ardipithecus and Australopithecus and Homo sapiens , there were a number of anatomical and cultural changes that are the subject of study. The ability to walk upright, the use of tools, the development of speech are some key features that scientists think they have marked our evolution. The paleoanthropology attempts to understand how and when to have these transitions. Lucy is one of these crossroads.
fossils from other Australopithecus afarensis had old features like a small brain volume, a bony crest on the skull and facial bones thrown forward, that departed from the genus Homo . However, Lucy had characteristics that helped to understand the transition from the style of arboreal life and a bipedal lifestyle. The pelvic region of Lucy is more like gender Homo and the knee indicates that she walked right as us. In the region of Southern Africa, the expansion of savannas in the last million years ago may have been an important factor in the appearance of this type of movement.
For all this, the skeleton became important. “Lucy is precious. There is only one Lucy, and the aim is to study it as much as possible, “says Richard Ketcham, a geologist from the same university John Kappelman, quoted in the statement. The opportunity for a fresh look at the fossil came in 2008 when Lucy made a tour by the United States and entered the Computer Tomography Laboratory of High Resolution X-Ray of the University of Texas.
This equipment is used to analyze geological material like rocks. This time, instead of rocks, fossil analyzed. “The computer tomography is a non-destructive technique. So, can see the details and the internal arrangements of the bones, “explains Richard Ketcham. For ten days, all of Lucy’s bones were analyzed.
The 35,000 new images required a reinterpretation of broken bones that had so far been associated with processes occurring after the death of Australopithecus. The tip of the right humerus (upper arm bone) has a fracture that is not usual to find the fossil preserving a series of sharp bone fragments remained in place. “This compression fracture occurs when the hand hits the ground during a fall, causing a clash between the shoulder bones,” said John Kappelman, who asked for help to the orthopedic surgeon Stephen Pearce, to interpret new information.
in addition to the humerus, the team identified fractures in his left shoulder, ankle, left knee, the pelvis and the first rib. According to scientists, the best way to explain the injuries set is that there was a big drop. According to the context of the local landscape, it appears that the fall will have been a tree.
“Poor Lucy!”
According to John Kappelman, it is very likely that the small Australopithecus seek food and pernoitasse in the trees, where he would be safe. There are studies on chimpanzee falling trees in these primates hit the ground at a 60 kilometers per hour. Lucy had less than 30 kilos, the scientists calculate that have fallen from a height of 12 meters and hit the ground at 56 kilometers per hour: the feet hit the ground first, then your hands. The fossil shows no trace of the fractures have healed. So death will have been almost instantaneous.
It is a “sad news, poor Lucy!”, Yves Coppens shoots with a hint of humor. This famous French paleoanthropologist was the one responsible for shipping in Hadar, where it found the remains of Australopithecus. “In general, arboreal primates are skilled, agile and have balance. After 20 years watching them (chimpanzees, gorillas) in their natural surroundings, have never seen such a thing [a fall] happen, “he tells AFP. “But a priori am not hostile to this thesis, though, is as valid as any other, especially if the researcher has argued well.”
The team argues that the fall may be related to the adaptations of this kind to bipedalism. “The adaptations that facilitated bipedal locomotion committed capacities of individuals from climbing the trees safely; this combination of features may have predisposed the species to falls, “reads the article Nature . For the team, find traumas like other fossils may help uncover the lifestyle of other hominids.
We’ll never know what caused the Lucy fall. One would have to be in that place, in the middle of Africa, there are 3.18 million years. But for John Kappelman, understanding how she died gives a dramatic dimension to this icon of paleoanthropology, “When I realized the extent of various injuries, Lucy’s image popped into my mind and I felt a sudden empathy across space and time. Lucy ceased to be a simple set of bones in a box, and in his death, became a real person:. A small body every party, abandoned on the edge of a tree “
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