A fossil from Ethiopia is letting scientists look deep into the past-- and they see a face looking back.The fossil is estimated to be 3.8 million years old.It helps complete the face for what scientists believe to bean ancestor of the species represented by Lucy-- the celebrated Ethiopian skeleton found in 1974.This species is the oldest known member of Australopithecus,a group of creatures that came before our own group of species.Scientists call it A. anamensis.They have known for a long time that the species existed.Fossil remains of it that are over 4 million years ago have been found.But remains of the species' face bones that had been found beforewere limited to pieces of jaws and teeth.This made it difficult to fully understand the species.The newly reported fossil includes much of the skull and face.The skull helps scientists learn about a specie's diet, brain size and appearance.The findings were described recently in the publication Nature.Yohannes Haile-Selassie helped write the report.He is with the Cleveland Museum of Natural History, in the American state of Ohio."This is a once-in-a-lifetime discovery," he told the Reuters news agency."We are talking about the most complete cranium of an early human ancestor ever found..."The face appears to be from a male.The middle and lower parts of the face jut out.In comparison, Lucy, the later skeleton, had a flatter mid-face.The change between the two shows a step toward the flat faces of humans today.The fossil also shows the beginning of the larger and very strong faces common to Australopithecus.Such facial structures helped the species eat hard food, researchers said.The fossil was found in 2016, in what once was a sandy area where a river entered a lake.At the time the creature lived, the area was mostly dry.Earlier research has shown that the A. anamensis possibly walked standing up on two feet.But there is no evidence that it used pieces of stone to make tools,Stephane Melillo told The Associated Press.Melillo, who also helped write the paper,is with the Max Planck Institute for Evolutionary Anthropology in Germany.Earlier findings have shown Lucy's species used stone tools.Experts not connected to the new study praised the work.Eric Delson of Lehman College in New York called the fossil "beautiful."He said the researchers did a good job of recreating the face in digital formto help scientists understand more about the species.Having a face for A. anamensis helps scientists "know how they lookedand how they differed from the Lucy species," said Zeray Alemseged.He is with the University of Chicago.William Kimbel directs the Institute of Human Origins at Arizona State University.He said the discovery helps offer new information on theearliest development of the Australopithecus group.The study's writers said the finding also shows that A. anamensisexisted for at least 100,000 years after producing Lucy's species, known as A. afarensis.That differs from the widely accepted ideathat there was no period of overlap, they wrote.Scientists care about overlap because its existence could show the processby which one species becomes another.However, several experts, including Kimbel, are not ready to support that idea.They say it is still not known how Lucy's species developed from an older one.