In the following years , he and John T. Robinson made a series of spectacular finds , including fragments from six hominids in Sterkfontein , which they named Plesianthropus transvaalensis , but which was later classified as an adult Australopithecus africanus , as well as more discoveries at sites in Kromdraai and Swartkrans . In the following years , he and John T. Robinson made a series of spectacular finds , including fragments from six hominids in Sterkfontein , which they named Plesianthropus transvaalensis , popularly called Mrs. Ples , but which was later classified as an adult Australopithecus africanus , as well as more discoveries at sites in Kromdraai and Swartkrans .