About the size of a small cat, the animal has four legs and a long tail. It's not a direct ancestor of monkeys and humans, but it provides a good indication of what such an ancestor may have looked like, researchers said at a news conference.
Because the skeleton is so remarkably complete, scientists believe it will provide a window into primate evolution. The animal was a juvenile female that scientists believe died at about 9 or 10 months.
"She tells so many stories. We have just started the research on this fabulous specimen," said Jorn Hurum, of the University of Oslo Natural History Museum, one of the scientists reporting the find.
The unveiling, at New York's Museum of Natural History, was promoted by a press release for the cable TV show History, which called it a "revolutionary scientific find that will change everything."
Mayor Michael Bloomberg, among the speakers at the news conference, called it an "astonishing breakthrough."
The story of the fossil find will be shown on History, which is owned by A&E Television Networks. A book also will be published.
Hurum saw nothing wrong with the heavy publicity which preceded the research's publication Tuesday in the scientific journal PLOS (Public Library of Science) One.
"That's part of getting science out to the public, to get attention. I don't think that's so wrong," Hurum said.