Scientists in Ethiopia have unearthed what may be the oldest and best-preserved skulls of modern man’s immediate predecessors, a finding that illustrates the dramatic transformation from the heavy-browed caveman look to more refined facial features.

The nearly complete skulls of an adult male and a child and the partial skull of a second adult are believed to be around 160,000 years old.

One scientist called the three skulls a “spectacular” find that illustrates a crucial stage of human evolution.

Discovered in Ethiopia’s fossil-rich Afar region, the skulls have clearly modern features a prominent forehead, flattened face and reduced brow that contrast with older humans’ projecting, heavy-browed skulls.

“They’re not quite completely modern, but they’re well on their way. They’re close enough to call Homo sapiens,” said Tim White, a University of California at Berkeley paleontologist who was co-leader of the international team that excavated and analyzed the skulls.

Previously, the earliest fossils of Homo sapiens found in Africa had been dated to about 130,000 to 100,000 years, although they were less complete and sometimes poorly dated, White said.

The new skulls, discovered in 1997, were described in today’s issue of Nature.

White and his colleagues assigned the new creatures to a subspecies of Homo sapiens they named Homo sapiens idaltu idaltu meaning “elder” in the Afar language.

Other scientists not involved with the research said the skulls were an important find that filled a big gap in the African human fossil record, the period between about 100,000 and 300,000 years ago.

The skulls’ age and appearance strongly support genetic evidence that modern humans arose in Africa between 100,000 and 200,000 years ago and not at multiple locations in Europe, Africa and Asia, as some researchers suggest.