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P. robustus hypodigm that comes from Swartkrans, but almost all researchers consider that taxon to be a junior synonym of P. robustus.

In 1959 Louis Leakey suggested that a new genus and species, Zinjanthropus boisei Leakey 1959, was needed to accommodate OH 5, a subadult cranium recovered in 1959 from Bed I, Olduvai Gorge, Tanzania. A year later John Robinson suggested that Z. boisei be subsumed into the genus Paranthropus as Paranthropus boisei, and in 1967 Phillip Tobias suggested it should be subsumed into Australopithecus, as Australopithecus boisei; in this review it is referred to as Paranthropus boisei (Leakey 1959) Robinson 1960. Additional fossils from Olduvai Gorge have subsequently been added to the hypodigm, as well as fossil evidence from the East African sites of Peninj, Omo Shungura, Konso, Koobi Fora, Chesowanja, and West Turkana. The temporal range of the taxon is ca. 2.3–1.4 Ma. P. boisei has a comprehensive craniodental fossil record, comprising several skulls and well-preserved crania, many mandibles, and isolated teeth. There is evidence of both large- and small-bodied individuals, and the range of the size difference suggests a substantial degree of body size sexual dimorphism despite its modest canine sexual dimorphism. P. boisei is the only hominin to combine a wide, flat face, massive premolars and molars, small anterior teeth, and a modest endocranial volume (ca. 480 cm3). The face of P. boisei is larger and wider than that of P. robustus, yet their brain volumes are similar. The mandible of P. boisei has a larger and wider body or corpus than any other hominin (see Paranthropus aethiopicus below) and the tooth crowns apparently grow at a faster rate than has been recorded for any other early hominin. There is no postcranial evidence that can with certainty be attributed to P. boisei (Wood and Constantino, 2009), but some of the postcranial fossils from Bed I at Olduvai Gorge currently attributed to H. habilis may belong to P. boisei. The fossil record of P. boisei extends across approximately 1 million years, during which there is little evidence of any substantial change in the size or shape of the components of the cranium, mandible, and dentition (Wood et al., 1994).

The taxon Paranthropus aethiopicus (Arambourg and Coppens, 1968) Chamberlain and Wood 1985 was introduced as Paraustralopithecus aethiopicus to accommodate Omo 18.18 (or 18.1967.18), an edentulous adult mandible recovered in 1967 from Omo Shungura in Ethiopia. Other contributions to the hypodigm of this taxon have come from West Turkana and Kenya and probably also from Melema, Malawi, and Laetoli, Tanzania. The hypodigm is small, but it includes a well-preserved adult cranium from West Turkana (KNM-WT 17000) together with mandibles (e.g., KNM-WT 16005) and isolated teeth from Omo Shungura (some also assign the Omo 338y-6 cranium to this taxon). No published postcranial fossils have been assigned to P. aethiopicus, but a proximal tibia from Laetoli may belong to P. aethiopicus. The temporal range of



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