Scientists have discovered a tiny species of ancient human that lived 18,000 years ago on an isolated island east of the Java Sea -- a prehistoric hunter in a "lost world" of giant lizards and miniature elephants.

These "little people" stood about three feet tall and had heads the size of a large grapefruit. They coexisted with modern humans for thousands of years yet appear to be more closely akin to a long-extinct human ancestor.

Researchers suspect the earlier ancestor may have migrated to the island and evolved into a smaller dwarf species as it adapted to the island's limited resources. This phenomenon, which scientists have come to call the "island rule," is common in the animal world but had never been seen in human evolution.

Colleagues marveled at the find as an evolutionary aberration -- an archaic human that survived to a time when Neanderthals, which had been thought to be the last pre-modern species to share the planet with modern humans, had probably been extinct for more than 10,000 years.

The research team from Australia's University of New England discovered the new species in a limestone cave on Flores Island, in the Indonesian archipelago, east of Java. It described the remains -- a fairly complete skull, the jawbone and much of the skeleton -- as those of a 30-year-old woman. The team named her Homo floresiensis. The team also found a tooth and a few bones from two other skeletons.

-- Guy Gugliotta

An artist's rendition of Homo floresiensis, which was three feet tall with a head the size of a grapefruit.