Ida (Plate B) joins Lucy on display in New York

When Lucy's Legacy: The Hidden Treasures of Ethiopia opens in Times Square, visitors will have the opportunity to view Plate B of the Darwinius masillae fossil, nicknamed "Ida." At 47 million years old, this fossil is a window into the primate past, when the key adaptations of opposable thumb and big toe had just evolved.

Two separate plates of rock comprise the original Ida fossil. One plate is the layer of sediments upon which the animal lay in death, and the other is the layer of sediments that buried her remains, entombing her during the process of fossilization. Upon her discovery in the early 1980s, these rock layers split apart, with a portion of the Ida fossil on the upper plate and the remainder of the specimen on the lower plate.

The original fossil Ida (Plate B) will be on public display for the first time in the Lucy’s Legacy exhibition. The original fossil Ida (Plate A) is currently on view in Norway at the Zoological Museum at the University of Oslo. Surprisingly, the Plate B fossil had been published and discussed within the scientific community almost a decade before the existence of Plate A was announced.

As reported in the scientific paper recently released by Hurum and his colleagues, some parts of Ida, particularly the hands, feet and tail, are represented only in Plate A. Plate B is valuable and unique because it shows stomach contents—one of the very few primate fossils that gives us clear evidence of what our ancient relatives ate. Plate B also has exquisitely preserved sectors of teeth and jaws.

The Plate B slab has been restored with great accuracy from Plate A, allowing visitors to the exhibition to see the details of the fingers and toes which let Ida run with acrobatic skill through the Eocene forests.