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Paranthropus
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Paranthropus boisei Paranthropus robustus Thematic map of sub-Saharan Africa showing major sites where hominid fossils have been found, including locations in Ethiopia, Kenya, Tanzania, Chad, and South Africa. Different symbols indicate fossil discoveries of Australopithecus, Kenyanthropus, Ardipithecus, Orrorin, and Paranthropus. Major lakes and country borders are also marked for geographic context. A diagram showing the tentative evolutionary relationships among hominid species over the past four million years, with skull images and labeled species names connected by solid and dotted lines to indicate proposed evolutionary pathways.
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Paranthropus boisei
Paranthropus boisei Paleoanthropologists Carrie Mongle (left) and Meave Leakey arranging hand fossils from Paranthropus boisei specimen KNM-ER 101000. The structure of these bones suggests that the species was capable of both a strong grip and precise but limited hand and finger movements compatible with tool use and toolmaking.

Paranthropus

fossil primate genus
Also known as: robust australopithecine
Written by
John P. Rafferty
John P. Rafferty writes about Earth processes and the environment. He serves currently as the editor of Earth and life sciences, covering climatology, geology, zoology, and other topics that relate to...
John P. Rafferty
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Britannica Editors
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
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History
Top Questions

What is Paranthropus?

What are the three known species of Paranthropus?

What is significant about the OH 5 specimen?

Paranthropus, genus of extinct primates with a close, but not direct, relationship to modern human beings. The genus is known from numerous fossils in eastern and southern Africa that date to 2.9–1.2 million years ago (mya), during the Pliocene and Pleistocene epochs (5.3 million–11,700 years ago). Skulls associated with Paranthropus are characterized by a relatively flat face with prominent brow lines, a low-crowned head with a marked sagittal crest (a raised ridge of bone on the top of the head), and large molars. Paranthropus was first described in 1938, by South African paleontologist Robert Broom. The name of the genus is a Greek construction meaning “beside human” or “near human.”

Classification

Despite having such distinctive skull and facial characteristics, Paranthropus is not recognized universally: the paleontological community remains split over how to classify the three known species (P. aethiopicus, P. robustus, and P. boisei). The species are often referred to as “robust australopiths” because of their relatively large facial features, jaws, and molars. Although many paleontologists consider these physical characteristics sufficiently distinct to warrant their divergence from Australopithecus, others claim that they are too similar to those in Australopithecus to justify a separate genus.

Skulls attributed to P. aethiopicus (which lived about 2.7 million–2.3 mya) are similar to those of A. afarensis (3.8–2.9 mya). This suggests that P. aethiopicus could be a descendant of A. afarensis. Although there is no scientific consensus around the evolutionary relationship between P. robustus (1.8–1.5 mya) and P. aethiopicus, many paleontologists contend that P. boisei (2.3–1.2 mya) is likely a direct descendant of P. aethiopicus.

Fossil discoveries

Paranthropus robustus
Paranthropus robustusA pair of fossils belonging to the extinct hominid species Paranthropus robustus. “Eurydice” (right) is the most complete early hominid skull ever excavated and described as a female, whereas “Orpheus” (left) is the lower jawbone belonging to a male.

Fossil evidence of Paranthropus was first discovered in a cave at Kromdraai, South Africa, by a 15-year-old student named Gert Terblanche in 1938. The fragments—a collection of premolar and molar teeth—made their way to Robert Broom, who later went to the site with Terblanche to find additional fragments (including a large lower jaw). Together, these fragments made up TM 1517, the holotype (or benchmark specimen) of P. robustus, which was first described, in a paper by Broom, later that year.

Other fossils attributed to Paranthropus were found in South Africa in subsequent years. However, the first eastern African fossil, a single skull, was discovered by English-born archaeologist and paleoanthropologist Mary Leakey in Olduvai Gorge, Kenya, in 1959. Leakey’s husband, Kenyan archaeologist and anthropologist Louis Leakey, initially named the species Zinjanthropus boisei (which was later reclassified as P. boisei). The specimen was officially labeled OH 5 (Olduvai Hominid 5), but it was dubbed “Nutcracker Man” because of its large molars, which were indicative of a vegetarian diet. OH 5, which is also known as “Zinj,” displays a zygomatic arch (a bridge of bone that extends from the temporal bone at the side of the head around to the upper jawbone and cheekbone) larger than that of a modern human. It was dated to about 1.75 mya, and its discovery was remarkable, because it offered some of the strongest evidence that hominins evolved in Africa.

Other Notable Fossils of Paranthropus
  • SK 48 (P. robustus): A nearly complete skull with several canines and molars was discovered at Swartkrans, South Africa, in 1950. The skull, which has been dated to 1.8–1.5 million years ago (mya), is characterized by a reduced sagittal crest and other features suggesting that it might have belonged to a female.
  • Peninj mandible (P. boisei): A well-preserved fossil jaw containing a complete set of adult teeth was discovered in 1964 at Peninij, Tanzania. The jaw showed that, although P. boisei had large molars, it did not have the large canines and incisors characteristic of earlier primates.
  • KNM-ER 406 (P. boisei): A toothless but nearly complete skull of an adult male was unearthed in Koobi Fora, Kenya, in 1969. Dated to 1.7 mya, it possesses a prominent sagittal crest and a large zygomatic arch.
  • KNM-ER 732 A (P. boisei): A 1.7-million-year-old partial skull of a female, showing a reduced sagittal crest, was found at Koobi Fora in 1970. Along with KNM-ER 406 and SK 48, this fossil offered strong evidence of sexual dimorphism in P. boisei.
  • KNM-WT 17000 (P. aethiopicus): Known colloquially as the “Black Skull” and discovered near West Turkana, Kenya, in 1985, this specimen dates to roughly 2.5 mya. The cranium, which developed its dark color from the manganese-rich soil surrounding it, is characterized by prominent eyebrow ridges and a low-crowned head with a prominent sagittal crest. Although the specimen does not contain teeth, scientists speculate that it possessed massive molars.
  • DNH 7 (P. robustus): A partial skull and jawbone with remarkably well-preserved teeth belonging to a female was recovered near Johannesburg in 1994. Nicknamed “Eurydice,” the specimen has been dated to nearly 2.0 mya.
  • MLP-3000 (Paranthropus sp.): A lower jawbone discovered in the Afar region of Ethiopia in 2019. The fossil, which dates to between 2.9 million and 2.5 million years ago, is of an indeterminate species within the genus; it is the first evidence of Paranthropus in northern Ethiopia.

Since OH 5 was unearthed, several other fossils have been found and attributed to Paranthropus. They have provided clues to the size relationships between males and females and to the species’ capabilities. One of the most startling discoveries was announced in 2025, when a multinational group of researchers described a number of hand bones associated with P. boisei that may be the first evidence of tool use and toolmaking outside the genus Homo (see also hand tool). The structure of these bones suggests that the species was capable of both a strong grip and precise but limited hand and finger movements, which could have allowed P. boisei to fashion and use tools. In addition, the foot bones that were also part of this discovery suggest that Paranthropus walked upright in a manner similar to members of the genus Homo. The fossils, which also include teeth, wrist bones, and a skull, were unearthed between 2019 and 2021.

John P. Rafferty