埃塞俄比亚的化石表面可能是著名的“露西”的祖先（在线收听）

Ethiopian Fossil Face Could Be Ancestor of Famed ‘Lucy’

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 be an 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 before were 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.

A ‘once-in-a-lifetime discovery

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.

Praise for recreating the face of a species

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 form to help scientists understand more about the species.

Having a face for A. anamensis helps scientists “know how they looked and 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 the earliest development of the Australopithecus group.

The study’s writers said the finding also shows that A. anamensis existed for at least 100,000 years after producing Lucy’s species, known as A. afarensis. That differs from the widely accepted idea that there was no period of overlap, they wrote.

Scientists care about overlap because its existence could show the process by 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.

I’m Ashley Thompson.

Words in This Story

fossil - n. something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times and that you can see in some rocks?

species - n. a group of animals or plants that are similar and can produce young animals or plants : a group of related animals or plants that is smaller than a genus?

jaws - n.? either one of the two bones of the face where teeth grow

cranium - n.? skull

jut out - phrasal verb. to stick out, up, or forward?

evolution - n. a theory that the differences between modern plants and animals are because of changes that happened by a natural process over a very long time

anthropology - n.? the study of human races, origins, societies, and cultures?

overlap - n.? a part or amount that happens at the same time as something else