Paranthropus boisei is a species of australopithecine from the Early Pleistocene of East Africa about 2.5 to 1.15 million years ago. The holotype specimen, OH 5, was discovered by palaeoanthropologist Mary Leakey in 1959, and described by her husband Louis a month later. It was originally placed into its own genus as "Zinjanthropus boisei", but is now relegated to Paranthropus along with other robust australopithecines. However, it is argued that Paranthropus is an invalid grouping and synonymous with Australopithecus, so the species is also often classified as Australopithecus boisei.
Temporal range: Early Pleistocene, 2.5–1.15 Ma
|Reconstruction of the holotype specimen OH 5|
(Louis Leakey, 1959)
Robust australopithecines are characterised by heavily built skulls capable of producing high stresses and bite forces, and some of the largest molars with the thickest enamel of any known ape. P. boisei is the most robust of this group. Brain size was about 450–550 cc (27–34 cu in), similar to other australopithecines. Some skulls are markedly smaller than others, which is taken as evidence of sexual dimorphism where females are much smaller than males, though body size is difficult to estimate given only one specimen, OH 80, definitely provides any bodily elements. The presumed male OH 80 may have been 156 cm (5 ft 1 in) tall and 61.7 kg (136 lb) in weight, and the presumed female KNM-ER 1500 124 cm (4 ft 1 in) tall (though its species designation is unclear). The arm and hand bones of OH 80 and KNM-ER 47000 suggest P. boisei was arboreal to a degree and was possibly capable of manufacturing tools.
P. boisei was originally believed to have been a specialist of hard foods, such as nuts, due to its heavily built skull, but it was more likely a generalist feeder of predominantly abrasive C4 plants, such as grasses or underground storage organs. Like gorillas, the apparently specialised adaptations of the skull may have only been used with less desirable fallback foods, allowing P. boisei to inhabit a wider range of habitats than gracile australopithecines. P. boisei may have been able to make Oldowan stone tools and butcher carcasses. P. boisei mainly inhabited wet, wooded environments, and coexisted with H. habilis, H. rudolfensis, H. ergaster, and H. erectus. These were likely preyed upon by the large carnivores of the time, including big cats, crocodiles, and hyenas.
The first remains—Olduvai Hominin (OH) 3, a baby canine and large molar tooth—were unearthed in 1955 in Olduvai Gorge, Tanzania. On July 17, 1959, palaeoanthropologist Mary Leakey discovered a skull without a jaw, OH 5 in the same gorge. The remains were clearly australopithecine (not the genus Homo), and at the time, the only australopithecine genera described were Australopithecus by Raymond Dart and Paranthropus (the South African P. robustus) by Robert Broom, and there were arguments that Paranthropus was synonymous with Australopithecus. Palaeoanthropologist Louis Leakey (Mary's husband) believed the skull had a mix of traits from both genera, briefly listing 20 differences, and so used OH 5 as the basis for the new genus and species "Zinjanthropus boisei" on August 15, 1959. The genus name derives from the medieval term for East Africa, "Zanj", and the specific name was in honour of Charles Watson Boise, the Leakeys' benefactor.
Mary and Louis Leakey
Mary and Louis Leakey had conducted excavations in Tanzania since the 1930s, though most such work was postponed due to the outbreak of World War II. They returned in 1951, finding mostly ancient tools and fossils of extinct mammals for the next few years. On the morning of July 17, 1959, Louis felt ill and stayed at camp while Mary went out to Bed I's Frida Leakey Korongo (korongo is Swahili for gully; this one was named after Louis's ex-wife). Sometime around 11:00 a.m., she noticed a piece of bone that "seemed to be part of a skull" which had a "hominid look".
After dusting some topsoil away and finding "two large teeth set in the curve of a jaw", she drove back to camp exclaiming "I've got him!" They created a pile of stones around the exposed portion of the fossil to protect it from the weather. Active excavation began the following day; they had chosen to wait for photographer Des Bartlett to arrive so that a photographic record of the entire process of removal could be made. A partial cranium was fully unearthed August 6, though it had to be reconstructed from its fragments which were scattered in the scree.
Once he had examined the cranium, Louis determined it to be subadult, or adolescent, based on its dentition, and he and Mary began to call it "Dear Boy". He also believed that it was of a species ancestral to modern humans but a member of the subfamily Australopithecinae. In describing the fossilized hominid in his journal, Louis initially considered the classification Titanohomo mirabilis (wonderful Titan-like man), but he eventually dubbed their find Zinjanthropus boisei (East Africa man). Zinj is an ancient Arabic word for the East African coast; anthropus refers to the fossil's humanlike characteristics; and boisei refers to Charles Watson Boise, who had been making financial contributions to the Leakeys' work since 1948. This classification was eventually revised to Paranthropus boisei, though this remains a matter of contention since the genus Paranthropus is disputed because of morphological similarities to Australopithecus. In either case, 5 is the holotype of its species.
Analysis of OH 5
Louis wrote "A new fossil skull from Olduvai" for Nature the week following the excavation, detailing the titular find and the "living floor" of Bed I which was replete with fossils of other mammalian fauna. "The Newest Link in Human Evolution: The Discovery by L.S.B. Leakey of Zinjanthropus Boisei", his account of the dig, was published in the January 1960 issue of Current Anthropology. It was annotated by anthropologist Francis Clark Howell, who had been allowed to examine the Leakeys' Olduvai findings before public announcements of their discovery.
Louis also wrote "Finding the World's Earliest Man" for the September 1960 issue of National Geographic, estimating the fossil's age to be 600,000 years old. Garniss Curtis and Jack Evernden used potassium-argon dating to date Olduvai's Bed I to about 1.75 million years old. Such an application of geochronology was unprecedented at the time. The same process was used for OH 7, the holotype of Homo habilis (handy man).
|Zinj on display at the National Museum of Tanzania.|
After the cranium was reconstructed with a model of the absent mandible, contemporaneous newspapers referred to it as "Nutcracker Man" due to the large posterior teeth and jaws which gave it a resemblance to vintage nutcrackers. Phillip Tobias, a colleague of the Leakeys, has also received attribution for this nickname. Primitive tools fashioned out of rocks and bone were excavated at and around Olduvai's Bed I, sometimes called the FLK Zinjanthropus site since the finding of OH 5.
At the time of discovery, there was a resistance to erecting completely new genera based on single specimens. Consequently, the proposal of Zinjanthropus during the Fourth Pan-African Congress of Prehistorians, in July in the then Belgian Congo, was rejected and subsumed into Paranthropus. Dart made his now famous joke, "... what would have happened if [the A. africanus specimen] Mrs. Ples had met Dear Boy one dark night." The battle of the name went on for many years, and drove a wedge between Louis and Sir Wilfrid Le Gros Clark, from 1955, who took the Paranthropus view. On the other hand, it brought the Leakeys and Dr. Melville Bell Grosvenor of the National Geographic Society together. The Leakeys became international figures and had no trouble finding funds from then on.
Louis initially believed P. boisei to be a direct ancestor of modern humans (as evident from the title of his National Geographic article) and the maker of those tools found near its remains, but he withdrew this idea once he and Mary unearthed Homo habilis—which had a larger brain—in the same area less than two years later. Despite that, OH 5 made the Leakeys famous and brought more attention to the developing field of paleoanthropology. The cranium was taken to Kenya after its discovery and was there until January 1965 when it was placed on display in the Hall of Man at the National Museum of Tanzania in Dar es Salaam. It remains there as of 2009, still recognized by the name Zinjanthropus, or simply Zinj.
Soon after OH 5's discovery, Louis presented "Z. boisei" to the 4th Pan-African Congress on Prehistory in Kinshasa, Democratic Republic of the Congo. In 1960, American anthropologist John Talbot Robinson pointed out that the supposed differences are due to OH 5 being slightly larger than P. robustus, and so recommended the species be reclassified as P. boisei. Louis rejected Robinson's argument. Following this, it was debated if P. boisei was simply an East African variant of P. robustus until 1967 when South African palaeoanthropologist Phillip V. Tobias gave a far more detailed description of OH 5 in a monograph (edited by Louis). However, they still retained Zinjanthropus and recommended demoting it to subgenus level as Australopithecus (Zinjanthropus) boisei, considering Paranthropus to be synonymous with Australopithecus. Synonymising Paranthropus with Australopithecus was first suggested by anthropologists Sherwood Washburn and Bruce D. Patterson in 1951, who recommended limiting hominin genera to only Australopithecus and Homo.
By the time OH 5 was discovered, the Leakey's had spent 24 years excavating the area for early hominin remains, but had instead recovered mainly other animal remains as well as the Oldowan stone tool industry. Because OH 5 was associated with the tools and processed animal bones, they presumed it to have been the toolmaker. Attribution of the tools was promptly switched to the bigger-brained H. habilis upon its description in 1964. In 1965, OH 5 was dated to 1.75 million years ago based on potassium-argon dating of anortoclase crystals from an overlying tuff (volcanic ash) bed.
The first identified jawbone, Peninj 1, was discovered Lake Natron just north of Olduvai Gorge in 1964.:107 Especially from 1966 to 1975, several more specimens revealing facial elements were reported from the Shungura Formation, Ethiopia; Koobi Fora and Chesowanja, Kenya; and Omo and Konso, Ethiopia. Among the notable specimens found include the well preserved skull KNM-ER 406 from Koobi Fora in 1970.:108–109 In 1997, the first specimen with both the skull and jawbone (and also one of the largest specimens), KGA10-525, was discovered in Konso. In 1999, a jawbone was recovered from Malema, Malawi, extending the species' southernmost range over 2,000 km (1,200 mi) from Olduvai Gorge.:109 The first definitive bodily elements of P. boisei associated with facial elements, OH 80 (isolated teeth with an arm and a leg), were discovered in 2013. Previously, body remains lacking unambiguous diagnostic skull elements had been dubiously assigned to the species, namely the partial skeleton KNM-ER 1500 associated with a small jawbone fragment. OH 80 was also associated with Oldowan stone tools. In 2015, based on OH 80, American palaeoanthropologist Michael Lague recommended assigning the isolated humerus specimens KNM-ER 739, 1504, 6020, and 1591 from Koobi Fora to P. boisei. In 2020, the first associated hand bones were reported, KNM-ER 47000 (which also includes a nearly complete arm), from Ileret, Kenya.
The genus Paranthropus (otherwise known as "robust australopithecines") typically includes P. boisei, P. aethiopicus, and P. robustus. It is debated if Paranthropus is a valid natural grouping (monophyletic) or an invalid grouping of similar-looking hominins (paraphyletic). Because skeletal elements are so limited in these species, their affinities with each other and to other australopithecines is difficult to gauge with accuracy. The jaws are the main argument for monophyly, but such anatomy is strongly influenced by diet and environment, and could in all likelihood have evolved independently in P. boisei and P. robustus. Proponents of monophyly consider P. aethiopicus to be ancestral to the other two species, or closely related to the ancestor. Proponents of paraphyly allocate these three species to the genus Australopithecus as A. boisei, A. aethiopicus, and A. robustus.:117–121
Before P. boisei was described (and P. robustus was the only member of Paranthropus), Broom and Robinson continued arguing that P. robustus and A. africanus (the then only known australopithecines) were two distinct lineages. However, remains were not firmly dated, and it was debated if there were indeed multiple hominin lineages or if there was only 1 leading to humans. In 1975, the P. boisei skull KNM-ER 406 was demonstrated to have been contemporaneous with the H. ergaster skull KNM ER 3733, which is generally taken to show that Paranthropus was a sister taxon to Homo, both developing from some Australopithecus species, which at the time only included A. africanus. In 1979, a year after describing A. afarensis from East Africa, anthropologists Donald Johanson and Tim D. White suggested that A. afarensis was instead the last common ancestor between Homo and Paranthropus, and A. africanus was the earliest member of the Paranthropus lineage or at least was ancestral to P. robustus, because A. africanus inhabited South Africa before P. robustus, and A. afarensis was at the time the oldest known hominin species at roughly 3.5 million years old. Now, the earliest known South African australopithecine ("Little Foot") dates to 3.67 million years ago, contemporaneous with A. afarensis.
Such arguments are based on how one draws the hominin family tree, and the exact classification of Australopithecus species with each other is quite contentious. For example, if the South African A. sediba (which evolved from A. africanus) is considered the ancestor or closely related to the ancestor of Homo, then this could allow for A. africanus to be placed more closely related to Homo than to Paranthropus. This would leave the Ethiopian A. garhi as the ancestor of P. aethiopicus instead of A. africanus (assuming Paranthropus is monophyletic, and that P. aethiopicus evolved at a time in East Africa when only A. garhi existed there).
Because P. boisei and P. aethiopicus are both known from East Africa and P. aethiopicus is only confidently identified from the skull KNM WT 17000 and a few jaws and isolated teeth, it is debated if P. aethiopicus should be subsumed under P. boisei or if the differences stemming from archaicness justifies species distinction. The terms P. boisei sensu lato ("in the broad sense") and P. boisei sensu stricto ("in the strict sense") can be used to respectively include and exclude P. aethiopicus from P. boisei when discussing the lineage as a whole.:106–107
P. aethiopicus is the earliest member of the genus, with the oldest remains, from the Ethiopian Omo Kibish Formation, dated to 2.6 million years ago (mya) at the end of the Pliocene. It is possible that P. aethiopicus evolved even earlier, up to 3.3 mya, on the expansive Kenyan floodplains of the time. The oldest P. boisei remains date to about 2.3 mya from Malema. The youngest record of P. boisei comes Olduvai Gorge (OH 80) about 1.34 mya; however, due a large gap in the hominin fossil record, P. boisei may have persisted until 1 mya.:109 P. boisei changed remarkably little over its nearly 1 million year existence.
P. boisei is the most robust of the robust australopithecines, whereas the South African P. robustus is smaller with comparatively more gracile features.:120 The P. boisei skull is heavily built, and features a defined brow ridge, receding forehead, rounded bottom margins of the eye sockets, inflated and concave cheek bones, a thick palate, and a robust and deep jawbone. This is generally interpreted as having allowed P. boisei to resist high stresses while chewing, though the thick palate could instead be a byproduct of facial lengthening. The skull features large rough patches (rugosities) on the cheek and jawbones, and males have pronounced sagittal (on the midline) and temporonuchal (on the back) crests, which indicate a massive masseter muscle (used in biting down) placed near the front of the head (increasing mechanical advantage). This is typically considered to be evidence of a high bite force.
The incisors and canines are reduced, which would hinder biting off chunks of large food pieces. In contrast, the cheek teeth of both sexes are enormous (postcanine megadontia), which would have increased the pressure applied to food. In the upper jaw, the 1st molar averages roughly 250 mm2 (0.39 sq in), the 2nd molar 320 mm2 (0.50 sq in), and the 3rd molar 315 mm2 (0.488 sq in); in the lower jaw, the 1st molar averages roughly 260 mm2 (0.40 sq in), the 2nd molar 315 mm2 (0.488 sq in), and the 3rd molar 340 mm2 (0.53 sq in). The molars are bunodont, featuring low and rounded cusps. The premolars resemble molars (are molarised), which may indicate P. boisei required an extended chewing surface for processing a lot of food at the same time. The enamel on the cheek teeth are among the thickest of any known ape, which would help resist high stresses while biting.:128–132
In a sample of 10 P. boisei specimens, brain size varied from 444–545 cc (27.1–33.3 cu in) with an average of 487.5 cc (29.75 cu in). However, the lower-end specimen, Omo L338‐y6, is a juvenile, and many skull specimens have a highly damaged or missing frontal bone which can alter brain volume estimates. The brain volume of australopithecines generally ranged from 400–500 cc (24–31 cu in), and for contemporary Homo 500–900 cc (31–55 cu in). Regarding the dural venous sinuses, in 1983, American neuroanthropologist Dean Falk and anthropologist Glenn Conroy suggested that, unlike A. africanus or modern humans, all Paranthropus (and A. afarensis) had expanded occipital and marginal (around the foramen magnum) sinuses, completely supplanting the transverse and sigmoid sinuses. In 1988, Falk and Tobias demonstrated that hominins can have both an occipital/marginal and transverse/sigmoid systems concurrently or on opposite halves of the skull, such as with the P. boisei specimen KNM-ER 23000. In 1983, French anthropologist Roger Saban stated that the parietal branch of the middle meningeal artery originated from the posterior branch in P. boisei and P. robustus instead of the anterior branch as in earlier hominins, and considered this a derived characteristic due to increased brain capacity. It has since been demonstrated that the parietal branch could originate from either the anterior or posterior branches, sometimes both in a single specimen on opposite sides of the skull as in KNM-ER 23000 and OH 5.
The wide range of size variation in skull specimens seems to indicate a great degree of sexual dimorphism with males being notably bigger than females. However, it is difficult to predict with accuracy the true dimensions of living males and females due to the lack of definitive P. boisei skeletal remains, save for the presumed male OH 80. Based on an approximation of 400 mm (1.3 ft) for the femur before it was broken and using modern humanlike proportions (which is probably an unsafe assumption), OH 80 was about 156.3 cm (5 ft 2 in) tall in life. For comparison, modern human men and women in the year 1900 averaged 163 cm (5 ft 4 in) and 152.7 cm (5 ft), respectively. The femoral head, the best proxy for estimating body mass, is missing, but using the shaft, OH 80 weighed about 50 kg (110 lb) assuming humanlike proportions, and 61.7 kg (136 lb) using the proportions of a non-human ape. The ambiguously attributed, presumed female femur KNM-ER 1500 is estimated to have been of an individual about 124 cm (4 ft 1 in) tall which would be consistent with the argument of sexual dimorphism, but if the specimen does indeed belong to P. boisei, it would show a limb anatomy quite similar to that of the contemporary H. habilis.:116
Instead, the OH 80 femur, more like H. erectus femora, is quite thick, features a laterally flattened shaft, and indicates similarly arranged gluteal, pectineal, and intertrochanteric lines around the hip joint. Nonetheless, the intertrochanteric line is much more defined in OH 80, the gluteal tuberosity is more towards the midline of the femur, and the mid-shaft in side-view is straighter, which likely reflect some difference in load-bearing capabilities of the leg. Unlike P. robustus, the arm bones of OH 80 are heavily built, and the elbow joint shows similarities to that of modern gibbons and orangutans. This could either indicate that P. boisei used a combination of terrestrial walking as well as suspensory behaviour, or was completely bipedal but retained an ape-like upper body condition from some ancestor species due to a lack of selection to lose them. In contrast, the P. robustus hand is not consistent with climbing. The hand of KNM-ER 47000 shows Australopithecus-like anatomy lacking the third metacarpal styloid process (which allows the hand to lock into the wrist to exert more pressure), a weak thumb compared to modern humans, and curved phalanges (finger bones) which are typically interpreted as adaptations for climbing. Nonetheless, despite lacking a particularly forceful precision grip like Homo, the hand was still dextrous enough to handle and manufacture simple tools.
In 1954, Robinson suggested that the heavily built skull of Paranthropus (at the time only including P. robustus) was indicative of a specialist diet specifically adapted for processing a narrow band of foods. Because of this, the predominant model of Paranthropus extinction for the latter half of the 20th century was that it was unable to adapt to the volatile climate of the Pleistocene, unlike the much more adaptable Homo. It was also once thought P. boisei cracked open nuts and similar hard foods with its powerful teeth, giving OH 5 the nickname "Nutcracker Man".
However, in 1981, English anthropologist Alan Walker found that the microwearing patterns on the molars were inconsistent with a diet high in hard foods, and were effectively indistinguishable from the pattern seen in the molars of fruit-eating (frugivorous) mandrills, chimpanzees, and orangutans. The microwearing on P. boisei molars is different than that on P. robustus molars, and indicates that P. boisei, unlike P. robustus, very rarely ever ate hard foods. Carbon isotope analyses report a diet of predominantly C4 plants, such as low quality and abrasive grasses and sedges. Thick enamel is consistent with grinding abrasive foods. The microwear patterns in P. robustus have been thoroughly examined, and suggest that the heavy build of the skull was only relevant when eating less desirable fallback foods. A similar scheme may have been in use by P. boisei. Such a strategy is similar to that used by modern gorillas, which can sustain themselves entirely on lower quality fallback foods year-round, as opposed to lighter built chimps (and presumably gracile australopithecines) which require steady access to high quality foods.
In 1980, anthropologists Tom Hatley and John Kappelman suggested that early hominins (convergently with bears and pigs) adapted to eating abrasive and calorie-rich underground storage organs (USOs), such as roots and tubers. Since then, hominin exploitation of USOs has gained more support. In 2005, biological anthropologists Greg Laden and Richard Wrangham proposed that Paranthropus relied on USOs as a fallback or possibly primary food source, and noted that there may be a correlation between high USO abundance and hominin occupation. In this model, P. boisei may have been a generalist feeder with a predilection for USOs, and may have gone extinct due to an aridity trend and a resultant decline in USOs in tandem with increasing competition with baboons and Homo. Like modern forest chimps and baboons, australopithecines likely foraged for food in the cooler morning and evening instead of in the heat of the day.
OH 80 was found associated with a mass of Oldowan stone tools and animal bones bearing evidence of butchery. This could potentially indicate P. boisei was manufacturing the Oldowan tradition and ate meat to some degree.
In 1979, American biological anthropologist Noel T. Boaz noticed that the relative proportions between large mammal families at the Shungura Formation are quite similar to the proportion in modern-day across sub-Saharan Africa. Boaz believed that hominins would have had about the same population density as other large mammals, which would equate to 0.006–1.7 individuals per square kilometre (0.4 square miles). Alternatively, by multiplying the density of either bovids, elephants, or hippos by the percentage of hominin remains out of total mammal remains found at the formation, Boaz estimated a density of 0.001–2.58 individuals per square kilometre. Biologist Robert A. Martin considered population models based on the number of known specimens to be flimsy. In 1981, Martin applied equations formulated by ecologists Alton S. Harestad and Fred L. Bunnel in 1979 to estimate the home range and population density of large mammals based on weight and diet, and, using a weight of 52.4 kg (116 lb), he got: 130 ha (320 acres) and 0.769 individuals per square kilometre if herbivorous; 1,295 ha (3,200 acres) and 0.077 individuals if omnivorous; and 287,819 ha (711,220 acres) and 0.0004 individuals if carnivorous.
A 2017 study postulated that, because male non-human great apes have a larger sagittal crest than females (particularly gorillas and orangutans), the crest may be influenced by sexual selection in addition to supporting chewing muscles. Further, the size of the sagittal crest (and the gluteus muscles) in male western lowland gorillas has been correlated with reproductive success. They extended their interpretation of the crest to the males of Paranthropus species, with the crest and resultantly larger head (at least in P. boisei) being used for some kind of display. This contrasts with other primates which flash the typically engorged canines in agonistic display (the canines of Paranthropus are comparatively small). However, it is also possible that male gorillas and orangutans require larger temporalis muscles to achieve a wider gape to better display the canines.
Australopithecines are generally considered to have had a faster, apelike growth rate than modern humans largely due to dental development trends. Broadly speaking, the emergence of the first permanent molar in early hominins has been variously estimated anywhere from 2.5 to 4.5 years of age, which all contrast markedly with the modern human average of 5.8 years. The tips of the mesial cusps of the 1st molar (on the side closest to the premolar) of KNM-ER 1820 were at about the same level as the cervix (where the enamel meets the cementum) of its non-permanent 2nd premolar. In baboons, this stage occurs when the 1st molar is about to erupt from the gums. The tooth root is about 5 mm (0.20 in), which is similar to most other hominins at this stage. In contrast, the root of the P. robustus specimen SK 62 was 6 mm (0.24 in) when emerging through the dental alveolus (an earlier stage of development than gum emergence), so, unless either specimen is abnormal, P. robustus may have had a higher tooth root formation rate. The specimen's 1st molar may have erupted 2–3 months before death, so possibly at 2.7–3.3 years of age. In modern apes (including humans), dental development trajectory is strongly correlated with life history and overall growth rate, but it is possible that early hominins simply had a faster dental trajectory but a slower life history due to environmental factors, such as early weaning age as is exemplified in modern indriid lemurs.
P. boisei remains have been found predominantly in what were wet, wooded environments, such as wetlands along lakes and rivers, wooded or arid shrublands, and semiarid woodlands, with the exception of the savanna-dominated Malawian Chiwondo Beds. During the Pleistocene, there seems to have been coastal and montane forests in Eastern Africa. More expansive river valleys–namely the Omo River Valley–may have served as important refuges for forest-dwelling creatures. Being cut off from the forests of Central Africa by a savanna corridor, these East African forests would have promoted high rates of endemism, especially during times of climatic volatility. Australopithecines and early Homo likely preferred cooler conditions than later Homo, as there are no australopithecine sites that were below 1,000 m (3,300 ft) in elevation at the time of deposition. This would mean that, like chimps, they often inhabited areas with an average diurnal temperature of 25 °C (77 °F), dropping to 10 or 5 °C (50 or 41 °F) at night.
P. boisei coexisted with H. habilis, H. rudolfensis, and H. ergaster / H. erectus, but it is unclear how they interacted. To explain why P. boisei was associated with Oldowan tools despite not being the tool maker, Louis Leakey and colleagues, when describing H. habilis in 1964, suggested that one possibility was P. boisei was killed by H. habilis, perhaps as food. However, when describing P. boisei 5 years earlier, he said, "There is no reason whatever, in this case, to believe that the skull [OH 5] represents the victim of a cannibalistic feast by some hypothetical more advanced type of man." OH 80 seems to have been eaten by a big cat. The leg OH 35, which either belongs to P. boisei or H. habilis, shows evidence of leopard predation. Other likely Oldowan predators of great apes include the hunting hyaena Chasmaporthetes nitidula, the sabertoothed cats Dinofelis and Megantereon, and the crocodile Crocodylus anthropophagus.
- African archaeology
- Australopithecus africanus – Extinct hominid from South Africa
- Australopithecus sediba – Two-million-year-old hominin from the Cradle of Humankind
- Homo ergaster – Extinct species or subspecies of archaic human
- Homo habilis – Archaic human species from 2.1 to 1.5 mya
- Homo rudolfensis – Extinct hominin from the Early Pleistocene of East Africa
- Oldowan – Archaeological culture
- Paranthropus aethiopicus – Extinct species of hominin of East Africa
- Paranthropus robustus – Extinct species of hominin of South Africa
- Wood, Bernard; Doherty, Dandy; Boyle, Eve (2020-05-29). "Hominin Taxic Diversity". Oxford Research Encyclopedia of Anthropology. doi:10.1093/acrefore/9780190854584.013.194. ISBN 9780190854584. Retrieved 2021-04-19.
- Domínguez-Rodrigo, Manuel; Pickering, Travis Rayne; Baquedano, Enrique; Mabulla, Audax; Mark, Darren F.; Musiba, Charles; Bunn, Henry T.; Uribelarrea, David; Smith, Victoria; Diez-Martin, Fernando; Pérez-González, Alfredo; Sánchez, Policarpo; Santonja, Manuel; Barboni, Doris; Gidna, Agness; Ashley, Gail; Yravedra, José; Heaton, Jason L.; Arriaza, Maria Carmen (2013). "First Partial Skeleton of a 1.34-Million-Year-Old Paranthropus boisei from Bed II, Olduvai Gorge, Tanzania". PLoS ONE. 8 (12): e80347. doi:10.1371/journal.pone.0080347. ISSN 1932-6203. PMC 3855051.
- Tobias, P. V. (2006). "Homo habilis—A Premature Discovery: Remembered by One of Its Founding Fathers, 42 Years Later". The First Humans – Origin and Early Evolution of the Genus Homo. Vertebrate Paleobiology and Paleoanthropology. Springer, Dordrecht. pp. 7–15. doi:10.1007/978-1-4020-9980-9_2. ISBN 978-1-4020-9980-9.
- Leakey, L. S. B. (1959). "A new fossil skull from Olduvai". Nature. 185 (4685): 491. doi:10.1038/184491a0.
- Mary Leakey, My Search, 52–53, 83; Lewin & Foley, 234.
- Bowman-Kruhm, 66; Mary Leakey, Excavations, 227; Morell, 180–181.
- Mary Leakey, My Search, 75.
- Morell, 181.
- Mary Leakey, Excavations, 227.
- Cela-Conde & Ayala, 158; Morell, 183–184.
- Cracraft & Donoghue, 524; Deacon, 56; Morell, 183–184.
- Cela-Conde & Ayala, 158; Johanson, Edgar & Brill, 156
- Johanson, Edgar & Brill, 156; Morell, 183.
- Louis Leakey, "A new fossil skull from Olduvai", 491; Morell, 185–186.
- Bowman-Kruhm, 67; Cela-Conde & Ayala, 158; Cracraft & Donoghue, 524; Deacon, 56.
- Cela-Conde & Ayala, 158.
- Louis Leakey, "A new fossil skull from Olduvai", 491–493.
- Louis Leakey, "The Newest Link in Human Evolution", 76–77.
- Louis Leakey, "Finding the World's Earliest Man", 421–435; Morell, 196.
- Boaz, 17; Cela-Conde & Ayala, 159; Richard Leakey, 49; Morell, 196.
- Dunsworth, 79; Lewin & Foley, 235.
- Cachel, 48.
- Bowman-Kruhm, 66.
- Cachel, 48; Mary Leakey, My Search, 52–53, 74; Spencer, 610.
- Morell, Virginia. "Ancestral Passions: The Leakey Family and the Quest for Humankind's Beginnings". Touchstone, 2011. p. 193
- Wilkins & Wakefield, 161–226.
- Lewin & Foley, 235; Spencer, 610.
- Bowman-Kruhm, 66; Johanson, Edgar & Brill, 158.
- Staniforth, 155.
- Robinson, J. T. (1960). "The affinities of the new Olduvai australopithecines". Nature. 186 (4723): 456–458. doi:10.1038/186456a0.
- Washburn, S. L.; Patterson, B. (1951). "Evolutionary Importance of the South African 'Man-apes'". Nature. 167 (4251): 650–651. doi:10.1038/167650a0. PMID 14826894.
- Evernden, J. F.; Curtis, G. H. (1965-10-01). "The Potassium-Argon Dating of Late Cenozoic Rocks in East Africa and Italy [and Comments and Reply]". Current Anthropology. 6 (4): 342–385. doi:10.1086/200619. ISSN 0011-3204.
- Wood, Bernard; Constantino, Paul (2007). "Paranthropus boisei: Fifty years of evidence and analysis". American Journal of Physical Anthropology. 134 (Suppl 45): 106–32. doi:10.1002/ajpa.20732. PMID 18046746.
- Journal of Eastern African Research and Development. East African Literature Bureau. 1974. p. 129.
The mandible was discovered by Kamoya Kimeu in 1964, during an expedition conducted by Richard Leakey and Glynn Isaac.
- Virginia Morell (11 January 2011). Ancestral Passions: The Leakey Family and the Quest for Humankind's Beginnings. Simon and Schuster. p. 303. ISBN 978-1-4391-4387-2.
- Suwa, G.; Asfaw, B.; Beyene, Y.; White, T. D.; et al. (1997). "The first skull of Australopithecus boisei". Nature. 389 (6650): 489–492. doi:10.1038/39037. PMID 9333236.
- Domínguez-Rodrigo, M.; Pickering, T. R.; Baquedano, E.; et al. (2013). "First Partial Skeleton of a 1.34-Million-Year-Old Paranthropus boisei from Bed II, Olduvai Gorge, Tanzania". PLOS ONE. 8 (12): e80347. doi:10.1371/journal.pone.0080347. PMC 3855051. PMID 24339873.
- Lague, M. R. (2015). "Taxonomic identification of Lower Pleistocene fossil hominins based on distal humeral diaphyseal cross-sectional shape". PeerJ. 3: e1084. doi:10.7717/peerj.1084. PMC 4512774. PMID 26213653.
- Richmond, B. G.; Green, D. J.; Lague, M. R.; et al. (2020). "The upper limb of Paranthropus boisei from Ileret, Kenya". Journal of Human Evolution. 141: 102727. doi:10.1016/j.jhevol.2019.102727. PMID 32078931.
- Johanson, D. C.; White, T. D. (1979). "A Systematic Assessment of Early African Hominids". Science. 203 (4378): 321–330. doi:10.1126/science.104384. PMID 104384.
- Clarke, R. J.; Kuman, K. (2019). "The skull of StW 573, a 3.67 Ma Australopithecus prometheus skeleton from Sterkfontein Caves, South Africa". Journal of Human Evolution. 134: 102634. doi:10.1016/j.jhevol.2019.06.005. PMID 31446970.
- McNulty, K. P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?". Nature Education Knowledge. 7 (1): 2.
- Constantino, P. J.; Wood, B. A. (2007). "The Evolution of Zinjanthropus boisei". Evolutionary Anthropology. 16 (2): 49–62. doi:10.1002/evan.20130.
- Joordens, J. C. A.; Feibel, C. S.; Vonhof, H. B.; Schulp, A. S.; Kroon, D. (2019). "Relevance of the eastern African coastal forest for early hominin biogeography". Journal of Human Evolution. 131: 176–202. doi:10.1016/j.jhevol.2019.03.012. PMID 31182201.
- Wood, B.; Wood, C.; Konigsberg, L. (1994). "Paranthropus boisei: an example of evolutionary stasis?". American Journal of Physical Anthropology. 95 (2): 117–136. doi:10.1002/ajpa.1330950202. PMID 7802091.
- Wood, B.; Strait, D. (2004). "Patterns of resource use in early Homo and Paranthropus". Journal of Human Evolution. 46 (2): 119–162. doi:10.1016/j.jhevol.2003.11.004. PMID 14871560.
- McCollum, M. A. (1998). "Palatal thickening and facial form in Paranthropus: Examination of alternative developmental models". American Journal of Physical Anthropology. 103 (3): 375–392. doi:10.1002/(SICI)1096-8644(199707)103:3<375::AID-AJPA7>3.0.CO;2-P. PMID 9261500.
- Wood, B. A.; Zuckerman, L. (1981). "Tooth Size and Shape and their Relevance to Studies of Hominid Evolution". Philosophical Transactions of the Royal Society B. 292 (1057): 71. doi:10.1098/rstb.1981.0014. JSTOR 2398644. PMID 6115408.
- Elton, S.; Bishop, L. C.; Wood, B. (2001). "Comparative context of Plio-Pleistocene hominin brain evolution". Journal of Human Evolution. 41 (1): 16. doi:10.1006/jhev.2001.0475. PMID 11414771.
- Hawks, J. (2011). "No brain expansion in Australopithecus boisei". American Journal of Physical Anthropology. 146 (2): 155–160. doi:10.1002/ajpa.21420. PMID 21915845.
- Tobias, P. V. (1987). "The brain of Homo habilis: A new level of organization in cerebral evolution". Journal of Human Evolution. 16 (7–8): 741–761. doi:10.1016/0047-2484(87)90022-4.
- McHenry, H. M. (1988). "Enlarged occipital/marginal sinuses and emissary foramina: Their significance in hominid evolution". In Grine, F. E. (ed.). Evolutionary History of the "Robust" Australopithecines. pp. 133–148. ISBN 978-1-351-52126-0.
- Saban, R. (1983). "Les veines méningées moyennes des Australopithèques". Bulletins et Mémoires de la Société d'Anthropologie de Paris (in French). 13 (3): 313–323. doi:10.3406/bmsap.1983.3905.
- Brown, B.; Walker, A.; Ward, C. V.; Leakey, R. E. (1993). "New Australopithecus boisei calvaria from East Lake Turkana, Kenya". American Journal of Physical Anthropology. 91 (2): 157. doi:10.1002/ajpa.1330910202. PMID 8317557.
- Roser, M.; Appel, C.; Ritchie, H. (2013). "Human Height". Our World in Data. Retrieved 16 June 2020.
- McHenry, H. M. (1991). "Femoral lengths and stature in Plio-Pleistocene hominids". American Journal of Physical Anthropology. 85 (2): 149–158. doi:10.1002/ajpa.1330850204. PMID 1882979.
- Ungar, P. S.; Grine, F. E.; Teaford, M. F. (2008). "Dental Microwear and Diet of the Plio-Pleistocene Hominin Paranthropus boisei". PLOS ONE. 3 (4): e2044. Bibcode:2008PLoSO...3.2044U. doi:10.1371/journal.pone.0002044. PMC 2315797. PMID 18446200.
- Walker, A. (1981). "Diet and teeth: Dietary hypotheses and human evolution". Philosophical Transactions of the Royal Society B. 292 (1057): 60–61. doi:10.1098/rstb.1981.0013. PMID 6115407.
- Ungar, Peter S.; Grine, Frederick E.; Teaford, Mark F. (April 2008). Petraglia, Michael (ed.). "Dental Microwear and Diet of the Plio-Pleistocene Hominin Paranthropus boisei". PLoS ONE. 3 (4): e2044. Bibcode:2008PLoSO...3.2044U. doi:10.1371/journal.pone.0002044. PMC 2315797. PMID 18446200.
- Scott, Robert S.; Ungar, Peter S.; Bergstrom, Torbjorn S.; Brown, Christopher A.; Grine, Frederick E.; Teaford, Mark F.; Walker, Alan (2005). "Dental microwear texture analysis shows within-species diet variability in fossil hominins". Nature. 436 (7051): 693–5. Bibcode:2005Natur.436..693S. doi:10.1038/nature03822. PMID 16079844.
- Cerling, Thure E.; Mbua, Emma; Kirera, Francis M.; Manthi, Fredrick Kyalo; Grine, Frederick E.; Leakey, Meave G.; Sponheimer, Matt; Unoa, Kevin T. (2011). "Diet of Paranthropus boisei in the early Pleistocene of East Africa". Proceedings of the National Academy of Sciences. 108 (23): 9337–41. Bibcode:2011PNAS..108.9337C. doi:10.1073/pnas.1104627108. PMC 3111323. PMID 21536914.
- Laden, G.; Wrangham, R. (2005). "The rise of the hominids as an adaptive shift in fallback foods: Plant underground storage organs (USOs) and australopith origins". Journal of Human Evolution. 49 (4): 482–498. doi:10.1016/j.jhevol.2005.05.007. PMID 16085279.
- Hatley, T.; Kappelman, J. (1980). "Bears, pigs, and Plio-Pleistocene hominids: A case for the exploitation of belowground food resources". Human Ecology. 8 (4): 371–387. doi:10.1007/BF01561000. JSTOR 4602571.
- Griffith, Cameron S.; Long, Byron L.; Sept, Jeanne M. (2010). "HOMINIDS: An agent-based spatial simulation model to evaluate behavioral patterns of early Pleistocene hominids". Ecological Modelling. 221 (5): 738–60. doi:10.1016/j.ecolmodel.2009.11.009.
- Macho, Gabriele A. (2014). "Baboon Feeding Ecology Informs the Dietary Niche of Paranthropus boisei". PLOS ONE. 9 (1): 84942. Bibcode:2014PLoSO...984942M. doi:10.1371/journal.pone.0084942. PMC 3885648. PMID 24416315.
- Dávid-Barrett, T.; Dunbar, R. I. M. (2016). "Bipedality and hair loss in human evolution revisited: The impact of altitude and activity scheduling". Journal of Human Evolution. 94: 72–82. doi:10.1016/j.jhevol.2016.02.006. PMC 4874949. PMID 27178459.
- Boaz, N. T. (1979). "Early Hominid Population Densities: New Estimates". Science. 206 (4418): 592–595. doi:10.1126/science.206.4418.592. PMID 17759430.
- Martin, R. A. (1981). "On extinct hominid population densities". Journal of Human Evolution. 10 (5): 427–428. doi:10.1016/s0047-2484(81)80006-1.
- Balolia, K. L.; Soligo, C.; Wood, B. (2017). "Sagittal crest formation in great apes and gibbons". Journal of Anatomy. 230 (6): 820–832. doi:10.1111/joa.12609. PMC 5442144. PMID 28418109.
- Kelley, J.; Schwartz, G. T. (2012). "Life-History Inference in the Early Hominins Australopithecus and Paranthropus". International Journal of Primatology. 33 (6): 1332–1363. doi:10.1007/s10764-012-9607-2.
- Bocherens, H.; Sandrock, O.; Kullmer, O.; Schrenk, F. (2011). "Hominin palaeoecology in late Pliocene Malawi: first insights from isotopes (13C, 18O) in mammal teeth". South African Journal of Science. 107 (3–4): 1–6. doi:10.4102/sajs.v107i3/4.331.
- Bobe, R. (2006). "The evolution of arid ecosystems in eastern Africa". Journal of Arid Environments. 66 (3): 564–584. Bibcode:2006JArEn..66..564B. doi:10.1016/j.jaridenv.2006.01.010.
- Leakey, L.; Tobias, P. V.; Napier, J. R. (1964). "A New Species of the Genus Homo from Olduvai Gorge" (PDF). Nature. 202 (4927): 7–9. Bibcode:1964Natur.202....7L. doi:10.1038/202007a0. PMID 14166722.
- de la Torre, I. (2011). "The origins of stone tool technology in Africa: a historical perspective". Philosophical Transactions of the Royal Society B. 366 (1567): 1030. doi:10.1098/rstb.2010.0350. PMC 3049100. PMID 21357225.
- Aramendi, K.; Arriaza, M. C.; Yravedra, J.; et al. (2019). "Who ate OH80 (Olduvai Gorge, Tanzania)? A geometric-morphometric analysis of surface bone modifications of a Paranthropus boisei skeleton". Quaternary International. 517: 118–130. doi:10.1016/j.quaint.2019.05.029.
- Njau, J. K.; Blumenschine, R. J. (2012). "Crocodylian and mammalian carnivore feeding traces on hominid fossils from FLK 22 and FLK NN 3, Plio-Pleistocene, Olduvai Gorge, Tanzania". Journal of Human Evolution. 63 (2): 408–417. doi:10.1016/j.jhevol.2011.05.008. PMID 21937084.
- Lee-Thorp, J.; Thackeray, J. F.; der Merwe, N. V. (2000). "The hunters and the hunted revisited". Journal of Human Evolution. 39 (6): 565–576. doi:10.1006/jhev.2000.0436. PMID 11102267.
- Brochu, C. A.; Njau, J.; Blumenschine, R. J.; Densmore, L. D. (2010). "A New Horned Crocodile from the Plio-Pleistocene Hominid Sites at Olduvai Gorge, Tanzania". PLOS ONE. 5 (2): e9333. Bibcode:2010PLoSO...5.9333B. doi:10.1371/journal.pone.0009333. PMC 2827537. PMID 20195356.
- Boaz, Noel (1998). Quarry Closing In On the Missing Link. New York: Simon & Schuster. ISBN 0-684-86378-2.
- Bowman-Kruhm, Mary (2005). The Leakeys: A Biography. Greenwood Publishing Group. ISBN 0-313-32985-0.
- Cachel, Susan (2006). Primate and Human Evolution. Cambridge: Cambridge University Press. ISBN 0-521-82942-9.
- Cela-Conde, Camilo; Francisco Ayala (2007). Human Evolution: Trails from the Past. Oxford: Oxford University Press. ISBN 0-19-856780-4.
- Cracraft, Joel; Michael Donoghue (2004). Assembling the Tree of Life. Oxford: Oxford University Press. ISBN 0-19-517234-5.
- Deacon, Jeanette (1999). Human beginnings in South Africa. Rowman Altamira. ISBN 0-7619-9086-0.
- Dunsworth, Holly (2007). Human Origins 101. Greenwood Publishing Group. ISBN 0-313-33673-3.
- Johanson, Donald; Blake Edgar (1996). From Lucy to Language. Principal photography by David Brill. New York: Simon & Schuster. ISBN 0-684-81023-9.
- Leakey, Louis (August 1959). "A new fossil skull from Olduvai". Nature. 184 (4685): 491–493. Bibcode:1959Natur.184..491L. doi:10.1038/184491a0. ISSN 0028-0836.
- Leakey, Louis (September 1960). "Finding the World's Earliest Man". National Geographic. 118 (3). ISSN 0027-9358.
- Leakey, Louis (January 1960). "The Newest Link in Human Evolution: The Discovery by L.S.B. Leakey of Zinjanthropus Boisei". Current Anthropology. 1 (1): 76. doi:10.1086/200077. ISSN 1537-5382.
- Leakey, Mary (1965). Olduvai Gorge. 3: Excavations in Beds I & II, 1960–1963. London: Cambridge University Press. ISBN 0-521-07723-0.
- Leakey, Mary (1979). Olduvai Gorge: My Search for Early Man. London: Collins. ISBN 0-00-211613-8.
- Leakey, Richard (1983). One Life. London: Michael Joseph. ISBN 0-7181-2247-X.
- Lewin, Roger; Robert Foley (2004). Principles of Human Evolution (2 ed.). Wiley-Blackwell. ISBN 0-632-04704-6.
- Morell, Virginia (1995). Ancestral Passions: The Leakey family and the Quest for Humankind's Beginnings. New York: Simon & Schuster. ISBN 0-684-82470-1.
- Spencer, Frank (1997). History of Physical Anthropology. Taylor & Francis. ISBN 0-8153-0490-0.
- Staniforth, Amy (March 2009). "Returning Zinj: curating human origins in twentieth-century Tanzania". Journal of Eastern African Studies. 3 (1). ISSN 1753-1055.
- Wilkins, Wendy & Wakefield, Jenny (1995). "Brain evolution and neurolinguistic preconditions". Behavioral and Brain Sciences. 18 (1): 161. doi:10.1017/s0140525x00037924. ISSN 0140-525X.
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