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Paranthropus: the robust hominins
c. 2.7–1.2 million years ago· Organism or group· Human ancestors & us
Well establishedStrong fossil, genetic or geological evidence.
A group of 'robust' hominins with massive jaws and teeth who lived alongside early Homo in Africa about 2.7–1.2 million years ago.
See it on the Life map →What happened
Three species are usually recognized: P. aethiopicus and P. boisei in East Africa, and P. robustus in South Africa. They had huge, flat molars with thick enamel, heavy jaws and, in males, a bony crest on top of the skull anchoring big chewing muscles. Their brains were about 450–550 cc. Despite the nickname 'Nutcracker Man', carbon isotopes in teeth show P. boisei ate mostly grasses and sedges.
Why it matters
Paranthropus shows that human evolution branched: one hominin line specialized in heavy chewing while another, Homo, bet on brains and tools. Only Homo survived.
The evidence (fossils, genes, rocks)
Skulls and teeth from Olduvai, Lake Turkana, Swartkrans and other sites; tooth wear, enamel isotopes and, recently, ancient proteins recovered from South African teeth.
Still debated
Whether they made stone tools, as finds at Nyayanga, Kenya, hint, and why they died out about 1.2 million years ago are open questions.
Connections (2)
▸Australopithecus probably also gave rise to Paranthropus: the robust homininsStrong evidence
The connection
Paranthropus appears about 2.7 million years ago, likely from an East African australopith. It took a different path from Homo: instead of bigger brains and tools, it evolved huge chewing teeth and jaw muscles for tough plant food. The two lines lived side by side for over a million years.
When and how
East Africa from about 2.7 million years ago (the 2.5-million-year-old 'Black Skull', West Turkana, Kenya, found 1985); South Africa about 2 million years ago.
How sure are we?
Skull and tooth features shared with earlier australopiths, especially A. afarensis, and its appearance in the fossil record soon after them.
Debates and open questions
Did East and South African robust forms descend from one ancestor, or evolve big jaws separately? The answer decides whether Paranthropus is one true group.
▸The Leakey family found the 1959 'Nutcracker Man' skull of Paranthropus: the robust homininsWell established
The connection
On 17 July 1959, Mary Leakey found a skull with huge molars at Olduvai Gorge. Louis named it Zinjanthropus boisei, and its dating to 1.75 million years, using the then-new potassium–argon method, made the Leakeys famous. It is now placed in Paranthropus boisei.
When and how
Olduvai Gorge, Tanzania, 1959 (Olduvai Hominid 5); dated in 1961 by Jack Evernden and Garniss Curtis using potassium–argon dating.
The evidence
The skull, catalogued as OH 5, is held in Tanzania. Later isotope studies of P. boisei teeth show it ate mostly grasses and sedges, not nuts.
Debates and open questions
Why Paranthropus died out about 1.2 million years ago while Homo survived is still debated; climate change and competition are both suggested.