A nomenclature debate among paleoanthropologists gives an alternative genus/species name for this robust East African australopith hominid population: Paranthropus boisei. In either case, this group of early hominids (extinct about 1.2 million years) is not on the direct ancestral line to contemporary Homo sapiens, standing instead in a cousin relationship to modern humans.
Adult females averaged about 3 1/2 feet in height, while adult males were about 5 feet tall.
The fossil skull shown here was the first of the East African robust australopiths found, by Mary Leakey at the base of the Olduvai Gorge in Tanzania, East Africa, in July 1959.
This skull, containing a complete set of upper teeth, shows with dramatic clarity the particular chewing evolutionary genetic response these hominids made to their specialized dietary ecological niche, involving as it did the grinding of many coarse, gritty vegetable dietary sources. They had extremely large molar teeth and chewing muscles, which attached at the top of the skull along the saggital crest shown, the purpose of which was to provide an anchoring spot for those powerful muscles. The ruggedness of the dental architecture of this specimen leads scholars to the conclusion that it was male; he carries a potassium/argon date of 1.8 million years.
This skull has come to have the personal nickname of "Zinj" after the original genus name (Zinjanthropus) which Mary and Louis Leakey suggested, a bit of nomenclature which did not become accepted by their fellow paleoanthropologists.
The cranial capacity of this skull measures out at 530 ml., a typical value for these hominids. There is a consensus among physical anthropologists that while these hominids most certainly used wooden tools for such tasks as digging up gritty roots and tubers as food sources, they probably did not manufacture stone tools.
They apparently became extinct because their specialized dietary ecological niche was too narrow a resource base to allow them to compete successfully with their contemporary omnivorous cousins of the genus Homo.
The catalog number for Zinj is OH 5.