A new study has revealed that humans existed 400,000 years before than previously believed. An international team of geoscientists and anthropologists dated the recently found Ledi-Geraru fossil mandible in the Afar region of Ethiopia to be between 2.8 and 2.75 million years old. The scientists also dated other fossils to between 2.84 and 2.58 million years ago, which helped reconstruct the environment in which the individual lived.
Lead author of the study, Erin N. DiMaggio, said, "The record of hominin evolution between 3 and 2.5 million years ago is poorly documented in surface outcrops, particularly in Afar, Ethiopia."
The recently discovered fossil, known by its catalog number LD 350-1, was dated using argon40 argon39 dating, a method that measures the different isotopes of argon and determines the age of the eruption that created the sample. DiMaggio said, "We were confident in the age of LD 350-1, as we used multiple dating methods including radiometric analysis of volcanic ash layers, and of which show that the hominin fossil was 2.8 to 2.75 million years old."
The results appear online in Science Express.