Robert Broom




In the mid-1920s, Dart's Taung Child discovery riveted Broom, who dropped in on Dart unannounced, reportedly dropped to his knees in adoration of the Taung Child, and then shifted the focus of his own research from fossil mammals to paleoanthropology. Broom's influence in the field was limited, but he realized that the Taung Child's status as a juvenile hampered its acceptance by the science community (juvenile apes look much more humanlike than adult apes) and that adults were needed.

Before South Africa was known for hominids, it was known for gold, and lime is useful in gold processing, so European settlers mined the limestone caves west of Johannesburg and Pretoria — with explosives — for many years. In 1936, Broom approached G.W. Barlow, the quarry supervisor at the Sterkfontein Caves. Barlow had worked at the quarry at Taung years earlier, so when Broom asked for fossils like the Taung Child, Barlow knew what he meant. Within days, Barlow gave Broom a fossil cast of a braincase. More digging found an associated skull, though a badly mangled one. But it was enough for Broom to declare it the type specimen of a new species: Plesianthropus transvaalensis. In 1947, Broom and his assistant John T. Robinson discovered another australopithecine fossil, this one in much better shape. Broom nicknamed this fossil Mrs. Ples. Both the type specimen and Mrs. Ples, whose gender is still a matter of debate, have been reclassified as Australopithecus africanus, and Mrs. Ples is estimated at 2.5 million years old.

Mrs. Ples fossil (left) and Robert Broom sculpture at Sterkfontein Cave (right). Photos by Michon Scott.

Paleontologists of all stripes face challenges in describing fossil species. If two individuals show considerable differences, is that just variation within one species, or two different species? Scientists who err on the side of grouping individuals together are called lumpers. Scientists who err in the opposite direction are called splitters, and Broom was known to be a notorious hominid splitter. Another of his arguments, which has better withstood the test of time, is that australopithecines came in two basic types: robust and gracile, and both walked upright. He found the remains of both types, and he defined the robust australopithecine Paranthropus robustus in 1938.

Broom excelled at finding fossils, due perhaps partly to his boundless energy. In his seventies, he could scramble up slippery fossil-laded slopes faster than people half his age. His success might have also been due to something else, something borrowed from miners: dynamite. He blasted overburden away from precious fossils — a practice that cracked Mrs. Ples's skull and hampered attaching accurate dates or contexts to multiple fossils. Broom argued that the rock was so hard, he really had no other choice. After the dust settled, Broom would appear crawling over the quarry looking for bones, wearing his trademark black suit.







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