SelamThe World’s Oldest Baby Vicki Hughes Anth1, Gavilan Fall 06
Dikika (4 kilometers from “Lucy”)
New Finds 1st afarensis Scapula found, good swinging / climbing ability Intact Hyoid Bone, “chimp-like” voice box and speech Curved fingers and toes, ability to climb. Biped maybe lived in trees.
Mosaic Evolution • Small-brained • Projecting face • Bipedal • Gorilla-like Scapula • Chimp-like Hyoid • Curved Fingers & Toes • Dependent youth ”This puts afarensis in a special position to play a pivotal role in the story of what we are and where we come from” Zeresenay Alemseged, Max Planck Institute
“But the most impressive difference between them is that this baby has a face” ~ Zeresenay Alemseged
On December 10th in the year 2000, in Ethiopia’s Afar region just four kilometers from where Lucy was found, a 3.3 million year old fossil belonging to a three-year old Australopithecus afarensis was discovered. The team had been digging in the Dikika region since early 1999 led by Ethiopian paleoanthropologist Zeresenay Alemseged. Dikika has a badlands reputation; the region is plagued by extreme heat, flash floods, malaria not to mention lions, hyenas, and other nocturnal guests. “It is one of the most difficult places on Earth to hunt for fossils-and one of the most fruitful” (Sloan, 2006). The team had found many fossils of other mammals such as elephants, hippopotamuses, rhinoceroses, and antelopes, Zeresenay knew that the team was on the right track he figured that if so many other mammals were living around the ancestral Awash River and the now gone shady woodlands that the extinct afarensis would also be one of those mammals. The fossil find is one of the most exciting finds because the bones are so well intact. The 3 year old Selam was found peering out from a dusty slope and tucked behind her intact skull was most of her upper torso that had been locked in sandstone. Zeresenay’s not sure how the baby died but suggests that the river must have rapidly buried the body in pebbles and sand, protecting it from scavengers and weather before gradually hardening into rock. The task of slowly etching away the hard sandstone from the delicate bones of Selam has taken Zeresenay over five years, and the task is still not complete. But what has emerged from the sandstone is a remarkably intact skeleton of a three-year old Australopithecus afarensis that lived 3.3 million years ago, pre dating Lucy by more than 100,000 years. The skeleton consists of a skull with brain endocast, full set of milk teeth and un-erupted adult teeth, scapula, ribs, spinal column, part of the humerus, several curled fingers, parts of the femur, knee and patella, tibia and fibula, and parts of the foot. More importantly an understanding of how afarensis children grow up to be adults is emerging. Anthropologists in every field are excited about learning what Selam’s skeleton can tell us. Selam’s bones are said to be a good example of mosaic evolution. Her remains have both human-like and ape-like characteristics. Her small brain, projecting face and the hyoid bone mimic that of a chimp. The size of her brain and the hint that at three her brain was no larger than a chimps might mean that brain growth may have started taking longer, “a change that prolonged the dependence of human young on their parent” (Sloan, 2006). It might have taken longer to reach adult size which is a human trait. The hyoid bone, which rarely ever found (the only one found in a Neanderthal), appears to be like that of a chimp, telling us that afarensis speech pattern was very similar to a chimps. The scapulas, the first to be found in this species, are very gorilla-like in appearance and function. Having an upward-facing shoulder socket may indicate that afarensis was very good at climbing. Which leads me to the fingers and toes, they are curved which also aids in climbing. The most important find with this skeleton has got to be the fact that evolution selects for one trait at a time. Afarensis was a capable biped with ape-like arms and digits, “A good example of mosaic evolution” (Wong, 2006), bipedalism was selected for first in the lower limbs then in the upper. “We’re getting to know more and more about the sequences of changes that produced a terrestrial biped from a tree-dwelling, apelike creature” (Wong, 2005)
Bibliography 1. (2006, 09/20 ). 'Lucy's baby, found in Ethiopa'. Retrieved December 11, 2006, from BBC News Web site: http://news.bbc.co.uk/ go/pr/fr/-/1/hi/sci/tech/5363328.stm 2. Wong, K (2006, Sep, 20th). Special Report: Lucy's Baby. Scientific American, Retrieved Dec 10, 2006, from www.sciam.com/ print_version.cfm?articleID=00076C1D-62D1-1511-A2D183414B7F0000 3. Sloan, Christopher (2006, November). Dikika Baby. National Geographic, Retrieved Dec 10, 2006, from http:/ /www7.nationalgeographic.com/ngm/0611/feature6/index.html