Dr. Timothy Bromage beside the museum's display of his "Lucy"
The American Museum of Natural History in New York is displaying NYU Dental Professor Timothy Bromage’s exquisitely-detailed image of a 3.2 million-year-old ancestral human bone in its newly-opened Anne and Bernard Spitzer Hall of Human Origins, the site of the most comprehensive exhibition the museum has ever mounted on the history of human evolution.
Dr. Bromage, an Adjunct Professor of Biomaterials and Biomimetics and of Basic Science and Craniofacial Biology, is a paleoanthropologist with a strong interest in bone evolution. The image displayed in the new exhibit hall, which opened on February 10, shows wisps of bone fiber thinner than a human hair in the thigh bone of “Lucy,” a partial skeleton discovered in 1974 in Ethiopia that is perhaps the best known specimen of Astralopithecus afarensis, an ancient ancestor of modern humans. Dr. Bromage used a microscope to photograph "Lucy" so he could compare her bone anatomy with that of other ancestral human species, as well as with modern humans.
The Hall of Human Evolution is believed to be the first major exhibition in the world to trace human development through a combination of evidence from the fossil record and genomic science. The advent of genomics over the past decade and recent advances in paleontology have made such a comprehensive examination of the nature of humanity possible. The museum chose to display Dr. Bromage’s image because it illustrates how advanced imaging technology has enabled paleoanthropologists to characterize fossil discoveries with unprecedented detail.
Dr. Bromage created the image while working in a high-security vault at the Ethiopian National Museum in Addis Ababa, where the original “Lucy” fossil is stored. He analyzed the specimen with the first microscope in the world equipped with portable confocal scanning, an advanced technology that allows scientists to easily observe details below a fossil’s surface without cutting and damaging the bone.
At the American Museum of Natural History, a reproduction of the microscopic photo -- which is color-coded green and white to highlight the different patterns of collagen in “Lucy’s” bone -- is exhibited in a glass case beside a life-size cast of her skeleton. Swirling white patterns of bone fiber are also superimposed onto a pair of wall panels, where they appear to float above the dioramas and fossil casts arrayed along the exhibit floor.
“Lucy’s” bone fiber composition bears a striking resemblance to bone fiber patterns in modern-day humans, an illustration of her well-developed ability to carry out daily activities in a bipedal posture,” Dr. Bromage says. “Although some scientists believe that Astralopithecus was well-adapted to climbing through trees, my analysis of the thigh bone supports the prevalent view that the species was almost exclusively bipedal.” Dr. Bromage’s future research will focus on the bone in “Lucy’s” upper arm to help determine the extent of her climbing activity.