NEW YORK (AP) - As he cleaned the dust and encrusted dirt from the bone in a box of fossils, Henry Galiano thought it might have come from an elephant or even a mastodon.

It turned out to be an important fossil - a human skull and one that may possibly be an important step in the evolution of man. An acquaintance walking by Galiano's shop from the nearby American Museum of Natural History helped identify it.

''This, if anything, has missing-link qualities, something in common with us,'' Galiano, 48, said yesterday.

Paleoanthropologists have concluded that the skull is a genuine specimen from Indonesia up to 1 million years old, and offers clues to a possible connection between Homo erectus, the ancient race that spread from Africa into Asia up to 2 million years ago, and Homo sapiens, or modern man.

What sets it apart is the shape of the skull - a high forehead and a brain cavity suggestive of speech or advanced mental capabilities, not previously seen in a human skull from that period and location.

The dark gray skull - an almost complete cranium but missing the upper and lower jaws - was delivered in March by a mysterious man who claimed to represent the estate of a collector, Galiano said.

The skull, anywhere from 100,000 to 1 million years old, probably belonged to a male in his 20s, scientists said.

The individual's brain was about half the size of that of Homo sapiens but within the range for Homo erectus.