Paleo Pals
Hello, my name is Australopithecus afarensis!
...But you can call me "Lucy"
Stats: Australopithecus afarensis
Lived: Between 3.8 and 2.9 million years ago
Latin: Southern Ape from Afar
Size: Males averaged 4 feet 11 inches and weighed around 92lbs (42 kg)
Females averaged 3 feet 5 inches and weighed around 64 lbs. (29 kg)
Distribution: Fossils found in Ethiopia, Kenya and Tanzania
On November 24, 1974, Paleoanthropologist (a scientist that studies the fossil remains of hominids) Donald Johanson, discovered nearly half of a skeleton of Australopithecus afarensis, whom he named “Lucy.” Lucy’s skeleton was so important because it was the most complete find of the time! Most fossil finds are usually just pieces of fossils like a tooth or a piece of the skull, so to find half a skeleton was quite the discovery! Lucy was also categorized as the “missing link” between humans and apes. Lucy’s skeleton showed similarities between both modern humans (us!) and chimpanzees, perhaps most importantly, it showed that Lucy was bipedal (she walked up-right just like you and I).
Shared skeletal similarities with Chimpanzees
1. The face of Australopithecus is more similar to a chimpanzee – the nose is flat and the lower jaw is projecting (prognathic, pushed outward)
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Au. afarensis skull ("Lucy") Chimpanzee skull Pan troglodytes
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2. The size of the braincase (the part of the skull where your brain is located) is more similar to chimpanzees than to modern humans.
Left to right: Chimpanzee, Au. afarensis and Homo sapien (modern human us)
3. Afarensis had long, strong arms, and a shoulder blade (scapula) similar to that of chimpanzee for climbing.
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4. Lucy had a triangular shaped / cone shaped rib cage, similar to those of modern apes.
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5. Similar canines (slightly more reduced – smaller) than that of chimpanzees.
Shared skeletal similarities with Homo sapiens (modern humans, that's us!)
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1. Lucy's femur bones were angled at the knee joint, this is referred to as a knock-knee, and is similar to our knees! This is one of the skeletal traits that helped "Lucy" walk bipedally (up-right).
2. Afarensis had a pelvis that is similar to our own. The shape of the pelvis is bowl-shaped - short and wide. This bowl-shaped pelvis also helped "Lucy" walk bipedally. (Put your hand on your hip, feel that bone? That's the illium - part of your pelvis)
3. Afarensis had toes that were in alignment and an arch in their foot. Both of these features helped "Lucy" walk bipedally. *Look at your feet, notice how your big toe is the longest and each toe gets shorter*
4. In the late 1970s, scientist, Mary Leakey discovered what is known as the Laetoli footprints. The footprints were made by Australopithecus afarensis as they walked through volcanic ash! Look closely, how many sets of footprints do you see?
Walking With Lucy!
Lifestyle
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Not much is known about the lives of Australopithecus. Scientists do believe that Australopithecus lived in social groups of multiple males and females. The fossil remains of the males show that they were much larger than the females, this is called "sexual dimorphism". This is also evidence for group living. Think about your family members, are the boys in your family bigger than the girls?
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Diet - What did they eat?
By studying the skeletal remains of their teeth and body, scientists are able to tell that they ate mostly plants and some meat. The shape of their rib cage and the enamel on their teeth are evidence for this.
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References:
https://www.britannica.com/topic/Australopithecus/media/44115/73032
https://sites.google.com/site/lucybyvanessa123456/home/facts-about-lucy
http://www.bbc.com/earth/story/20141127-lucy-fossil-revealed-our-origins
https://www.darwinandwallace.com/products/australopithecus-afarensis-model-skull-bh-001
http://www.efossils.org/book/how-big-was-lucys-brain
https://australianmuseum.net.au/learn/science/human-evolution/australopithecus-afarensis/
https://www.andywhiteanthropology.com/blog/category/australopithecines