About 3.3 million years old fossil unravels origins of human spine
An analysis of a fossil skeleton of 3.3 million years revealed parts of the structure of the human spine that have established effective walking movements much earlier than expected. The fossil, known as the “Selam”, is a nearly complete skeleton of a two and a half year old Dikika short, Ethiopia, in 2000.
“Continuous and meticulous research Selam shows the general structure of the human spine has emerged for over 3.3 million years, illuminating one of the characteristics of human evolution,” said Zeresenay (Zeray) Alemseged, a professor at the University Of Chicago and lead author of the new study.
Selam, meaning “peace” in the Amharic language of Ethiopia, was an early human relationship of the species Australopithecus afarensis – the same species as Lucy’s famous skeleton. Lucy is an early australopithecine sample and dates back to about 3.2 million years. It was found in the Awash Valley in Ethiopia in 1974.
“This kind of conservation is unprecedented, especially in a young person whose vertebrae are not yet fully fused,” Alemseged said. Many of the features of the spine and human rib cage are shared among primates. But the human spine also reflects our particular way of standing upright on two feet.
For example, humans have lesser thoracic vertebrae – the spine – those of our closest primate relatives. Humans also have more vertebrae in the lower back, which allows us to walk effectively. When and how this model has evolved has been unknown so far because complete sets of vertebrae are rarely conserved in the fossil record.
“Selam gave us the first glimpse of how the spines of our earliest ancestors were organized,” said Carol Ward, a professor at the University of Missouri School of Medicine and lead author of the study.
For the analysis, Selam had to make a trip. She traveled to the European Synchrotron Radiation Facility in Grenoble, France, where Alemseged and the research team used high-resolution imaging technology to visualize bone.
Explorations indicate that Selam had the distinct transition from the thoracic lumbar joint found in other human fossil relatives, but the specimen is the first to demonstrate that, like modern humans, our earliest ancestors had only twelve thoracic vertebrae And twelve pairs of ribs. This is cheaper than most monkeys.
The results were published in the journal Proceedings of the National Academy of Sciences.
“This unusual human initial setup may be a key in developing more precise scenarios for the evolution of bipeditude and the modern form of the human body,” Threra Nalley, a professor of anatomy at the Western University of Health Sciences in Pomona California, He is also an author on paper.
This configuration marks a transition to the kind of backbone that allows humans to be effective walkers and sports runners, which they are today.
“It is first documented in the fossil record of the appearance of the number of vertebrae in our history as the transition increased from coastal vertebra to the lower vertebra and when we began to enlarge,” Alemseged said.
“This structure and its modification over time is one of the key events in the history of human evolution,” Alemseged said.