A team of scientists has discovered a sample of what may be one of the earliest humans ever to walk the Earth.

According to BBC News, the sample found in Ethiopia is a jawbone that dates back 2.8 million years and could represent "the most important transitions in human evolution." More notably, the jawbone appears to provide a link to "Lucy," the noted ancient hominin that dates back 3.2 million years.

Brian Villmoare, of the University of Nevada in Las Vegas, said he and his research team are trying to make a solid connection between Lucy and the new finding.

"The moment I found it," he told BBC News, "I realized that it was important, as this is the time period represented by few (human) fossils in Eastern Africa."

The scientists published their study in the journal Nature.

"The importance of the specimen is that it adds a data point to a period of time in our ancestry in which we have very little information," William H. Kimbel, director of ASU's Institute of Human Origins, said in a press release. "This is a little piece of the puzzle that opens the door to new types of questions and field investigations that we can go after to try to find additional evidence to fill in this poorly known time period."

If the dating on the jawbone is correct, the first humans could have appeared 400,000 years earlier than previously thought.

"Previously, the oldest fossil attributed to the genus Homo was an upper jaw from Hadar, Ethiopia, dated to 2.35m years ago," Kimbel told BBC News. "So this new discovery pushes the human line back by 400,000 years or so, very close to its likely (pre-human) ancestor. Its mix of primitive and advanced features makes the Ledi jaw a good transitional form between (Lucy) and later humans."