Scientists on Wednesday unveiled a "remarkably complete" skull of an early human dating back 3.8 million years. It is considered the first discovery of its kind.

"This skull is one of the most complete fossils of hominids more than 3 millions years old," said Ethiopian paleoanthropologist Yohannes Haile-Selassie of the Cleveland Museum of Natural History.

The skull "looks set to become another celebrated icon of human evolution," said Fred Spoor of the Natural History Museum of London.

"This is a game-changer in our understanding of human evolution during the Pilocene," added Haile-Selassie. The discovery was announced in two studies published in the science journal Nature on Wednesday.

Read more: Iraq's drought unveils 3,400-year-old palace of mysterious empire

Early humans

Study co-author Stephane Melillo of the Leipzig-based Max Planck Institute for Evolutionary Anthropology said the fossil showcases the bridge between the species famously represented by Lucy and the oldest ancestors of modern humans.

"Until now, there was a big gap between the oldest human ancestors, which are about 6 million years old, and species like 'Lucy,' which are two to three million years old," said Melillo. The skull, however, "links the morphological space between these two groups."

The studies' authors also said the skull could be evidence that the two groups had co-existed.

But some scientists have dismissed that claim, such as Institute of Human Origins Director William Kimbel, saying there isn't sufficient evidence to prove that overlap between the two species occurred.

Read more: A crown or a bucket? When archaeologists make mistakes

Every evening, DW's editors send out a selection of the day's hard news and quality feature journalism. You can sign up to receive it directly here.

ls/rc (AFP, AP)