Professors in the College of Liberal Arts wear many hats. Along with teaching, they conduct groundbreaking research that can resonate worldwide.
Lucy, a 3.18-million-year-old specimen of Australopithecus afarensis — or “southern ape of Afar” — is among the oldest, most complete skeletons of any adult, erect-walking human ancestor. Since her discovery in the Afar region of Ethiopia in 1974, two questions remain: Did her species spend any time in trees, and how did she die?
During her U.S. exhibit tour in 2008, Lucy detoured to the High-Resolution X-ray Computed Tomography Facility in the Jackson School of Geosciences — a machine designed to scan through rock-solid materials at a higher resolution than medical CT scans can. For 10 days, anthropology professor John Kappelman and geological sciences professor Richard Ketcham carefully scanned and created a digital archive of Lucy’s 40-percent-complete skeleton.
Studying the CT scans years later, Kappelman noticed something unusual: The end of the right humerus was fractured in a manner not normally seen in fossils, preserving a series of sharp, clean breaks with tiny bone fragments and slivers still in place.
Kappelman, whose findings were published in Nature, identified the damage as a textbook case of a four-part proximal humerus fracture — a “compressive fracture [that] results when the hand hits the ground during a fall, impacting the elements of the shoulder against one another to create a unique signature on the humerus,” says Kappelman, who consulted and confirmed his hypothesis with Dr. Stephen Pearce, an orthopedic surgeon at Austin Bone and Joint Clinic, using a modern human-scale, 3-D printed model of Lucy.
“When the extent of Lucy’s multiple injuries first came into focus, her image popped into my mind’s eye, and I felt a jump of empathy across time and space,” Kappelman says. “Lucy was no longer simply a box of bones, but in death became a real individual: a small, broken body lying helpless at the bottom of a tree.”
Kappelman conjectured that because Lucy was both terrestrial and arboreal, features that permitted her to move efficiently on the ground may have compromised her ability to climb trees, predisposing her species to more frequent falls. Using fracture patterns when present, future research may tell a more complete story of how ancient species lived and died.
Learn more about Kappelman’s Lucy research on Life & Letters.
The College of Liberal Arts has more than 500 faculty members who are rigorous teachers and creative researchers who advance knowledge in the humanities and social sciences while preparing the next generation of thoughtful citizens and leaders. To learn more about our faculty, please visit the departmental directories listed below: