Reverend AtheiStar Posted September 21, 2006 Share Posted September 21, 2006 http://www.world-science.net/othernews/060...y-afarensis.htm “Lucy’s Baby”: pre-human fossil dazzles scientists Sept. 20, 2006 Special to World Science Researchers say they’ve unearthed the possibly most complete known fossil of a forebear of humans: a baby of the same species as the famed “Lucy” fossil found in 1974. Human-like below the waist, ape-like above, the tot is a “once-in-a-lifetime” find, said Ethiopian paleoanthropologist Zeresenay Alemseged, who led the scientific team credited with the discovery. Described as the skull of an Australopithecus afarensis baby, this measures about 12 cm (5 inches) from the bottom of the chin to the top of the head vertically. (Courtesy Zeresenay Alemseged; © Authority for Research and Conservation of Cultural Heritages). -------------------------------------------------------------------------------- The find revived memories of “Lucy,” believed to be a female in her mid-20s and hailed, when discovered, as the most complete known skeleton of a pre-human hominid. A hominid is a species on the human branch of the evolutionary tree. The new specimen, dubbed “Lucy’s baby” by some—though it’s actually thought to have lived a bit earlier than Lucy—is likewise causing a stir over its splendid condition. That, scientists say, makes it a treasure trove of additional clues to human origins. Years ago, Lucy, in many researchers’ view, overturned a widespread assumption: that our ancestors evolved intelligence first and upright walking later. She was seen to refute that because her bones suggested at least some upright-walking ability, yet a small, ape-like brain. This helped revive a notion proposed by Charles Darwin: that upright movement spurred brain evolution by freeing hands for tool use. Henceforth, success in the battle for survival would depend on ever-better tool use, and the brains to enable it. Like Lucy, the newfound child shows the marks of a species able to walk upright, researchers said; it also offers more clues to the evolution of that skill, and of the brain and speech. It’s a “mine of information about a crucial stage in human evolutionary history,” wrote paleobiologist Bernard Wood of George Washington University in Washington, D.C., in a commentary in the Sept. 21 issue of the research journal Nature. The scientists credited with the find described it in another paper in the same issue. They estimated that the infant died at age three, possibly in a flood that also buried it in pebbles and sand, helping preserve it. Artist's conception of a mother and child Australopithecus afarensis. Adult females of the species were some 3½ feet tall, judging from the "Lucy" specimen. -------------------------------------------------------------------------------- Lucy and the baby, which date to slightly more than three million years ago, are far from the oldest known members of the human family. That distinction belongs to the chimp-sized Sahelanthropus tchadensis or “Toumai Man,” estimated as seven million years old and found in Central Africa four years ago. But Lucy and the tot—said to represent a later species, Australopithecus afarensis—would be part of a burst of hominid diversity noted in the fossil record from four to two million years ago. This is thought to reflect some of the rich evolutionary experimentation that nature tossed up on the way to producing our species, Homo sapiens. Hominids of that period are collectively called Australopiths. Which lineage led to us is unknown, though. The newfound bundle of bones, found like Lucy in the Ethiopian desert, was also a female, and lived about 3.3 million years ago, its discoverers said. Lucy is thought to have lived 3.2 million years ago. “The most impressive difference between them is that this baby has a face,” said team leader Zeresenay (Ethiopians’ first names are their formal names.) This face gave away the species, added Zeresenay, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Also unlike Lucy—nicknamed after a Beatles song—the baby has fingers, a foot and a torso. Tooth structures clued researchers in to its rough age and its sex, they said, while the sediments that had trapped it revealed its time period. The tot helps explain how A. afarensis blurred ape-human boundaries, Zeresenay said: her shoulder blades resemble a young gorilla’s, suggesting she could climb trees, but her thigh bone is angled like humans’, implying good upright walking ability. Members of the species seem to have been foraging, upright walkers, capable of “climbing trees when necessary, especially when they were little,” he said. Zeresenay first led a band of fossil hunters into Ethiopia’s Dikika region in 1999, researchers recounted. Punishing heat, flash floods, malaria, wild beasts and occasional shootouts between rival ethnic groups plague the zone. On a shadeless December day the next year, the scientists recalled, they hunted under a pounding sun for the prize that had eluded them—our ape-like forebears. Team member Tilahun Gebreselassie then spotted the tot’s face, no bigger than a monkey’s, peering out from a dusty slope. Tucked beneath it in hard sandstone were more bones, the whole bundle of them no bigger than a canteloupe, one finger still curled in a tiny grasp, researchers said. Zeresenay found a rare example of a hyoid bone, a throat structure later crucial to human speech, he said. This offers a glimpse of the evolution of the voice box, which under some theories is interwoven with that of speech. Zeresenay spent the next five years scratching away rock from the skeleton with a dentist’s drill, according to members of his team. What killed the baby is unclear. But it seems the ancient Awash River rapidly buried the body in a flood, the scientists said, preserving rare details such as a full set of both milk teeth and unerupted adult teeth. The brain cast will help reveal “whether our earliest ancestors grew their brains in the uniquely human way,” said a member of the research group, Fred Spoor of University College London. One of her humanlike knees was complete with a kneecap no bigger than a dried pea, researchers said. But her upper body, like Lucy’s, had many apelike features: small brain, nose flat like a chimp’s, face projecting forward. Her two complete shoulder blades are the first found from an australopith, Zeresenay said; analyzing their function “will be among the exciting challenges that we will face.” Link to comment Share on other sites More sharing options...
scitsofreaky Posted September 21, 2006 Share Posted September 21, 2006 What an awesome find she is. One question to anyone who knows: do other primates have kneecaps? Link to comment Share on other sites More sharing options...
Reverend AtheiStar Posted September 26, 2006 Author Share Posted September 26, 2006 What an awesome find she is. One question to anyone who knows: do other primates have kneecaps? http://www.eskeletons.org/cmpAna/comparativeAnatomy.html I thought all primates did. Link to comment Share on other sites More sharing options...
scitsofreaky Posted September 26, 2006 Share Posted September 26, 2006 http://www.eskeletons.org/cmpAna/comparativeAnatomy.html I thought all primates did. Alrighty then. I barely know my ass from my hands when it comes to anatomy. That is a cool site Rev, thanks for sharing and answering my stupid question. Link to comment Share on other sites More sharing options...
Reverend AtheiStar Posted September 26, 2006 Author Share Posted September 26, 2006 http://www.eskeletons.org/cmpAna/comparativeAnatomy.html I thought all primates did. Alrighty then. I barely know my ass from my hands when it comes to anatomy. That is a cool site Rev, thanks for sharing and answering my stupid question. That's fine. I'm glad I could help. Link to comment Share on other sites More sharing options...
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