Paranthropus robustus was originally discovered in
Southern AfricaSouthern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
in 1938. The development of
P. robustus, namely in cranial features, seemed to be aimed in the direction of a "heavy-chewing complex". Because of the definitive traits that are associated with this robust line of
australopithecineThe term australopithecine refers generally to any species in the related genera Australopithecus or Paranthropus. These species occurred in the Plio-Pleistocene era, and were bipedal and dentally similar to humans, but with a brain size not much larger than modern apes, lacking the...
, anthropologist
Robert BroomProfessor Robert Broom was a Scottish South African doctor and paleontologist. He qualified as a medical practitioner in 1895 and received his DSc in 1905 from the University of Glasgow...
erected the genus
ParanthropusThe robust australopithecines, members of the extinct hominin genus Paranthropus , were bipedal hominids that probably descended from the gracile australopithecine hominids...
and placed this species into it.
Paranthropus robustus (considered for a time by the scientific community as
Australopithecus robustus) is generally dated to have lived between 2.0 and 1.2 million years ago.
P. robustus had large sagittal crests, jaws, jaw muscles, and post-canine teeth that were adapted to serve in the dry environment that they lived in.
After
Raymond DartRaymond Arthur Dart was an Australian anatomist and anthropologist, best known for his involvement in the 1924 discovery of the first fossil ever found of Australopithecus africanus, an extinct hominid closely related to humans, at Taung in the North of South Africa in the province...
’s discovery of
Australopithecus africanusAustralopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...
, Broom had been in favour of Dart's claims about
Australopithecus africanus being an ancestor of
Homo sapiens. Broom was a
ScottishScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
doctor then working in South Africa who began making his own excavation in
Southern AfricaSouthern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
to find more specimens, which Dart had found earlier. In 1938, at 70 years old, Broom, excavating at Kromdraai, South Africa discovered pieces of a skull and teeth which resembled Dart's
Australopithecus africanus find, but the skull had some "robust" characteristics. The fossils included parts of a skull and teeth; all dated to 2 million years old. Fossil sites found on
Paranthropus robustus are found only in
South AfricaThe Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
in Kromdraai,
SwartkransSwartkrans is a location in South Africa, around from Johannesburg.Swartkrans is a farm near to Sterkfontein, notable for being extremely rich in archaeological material, particularly hominid remains. It was purchased by the University of the Witwatersrand in 1968...
, Drimolen, Gondolin and
CoopersCooper's Cave is a series of fossil-bearing breccia filled cavities located almost exactly between the well known South African hominid-bearing sites of Sterkfontein and Kromdraai and about 40 km Northwest of the City of Johannesburg, South Africa.-Tools:...
. In the cave at Swartkrans, the remains of 130 individuals were discovered. The study made on the dentition of the hominins revealed that the average
P. robustus rarely lived past 17 years of age.
Paranthropus robustus became the first "robust" species of hominid ever uncovered well before
P. boiseiParanthropus boisei was an early hominin and described as the largest of the Paranthropus species...
and
P. aethiopicusParanthropus aethiopicus is an extinct species of hominid. The finding discovered in 1985 by Alan Walker in West Turkana, Kenya, KNM WT 17000 , is one of the earliest examples of robust pliocene hominids...
. Broom's first discovery of
P. robustus had been the first discovery of a robust australopithecine and the second australopithecine after
Australopithecus africanus, which Dart discovered. Broom's work on the australopithecines showed that the evolution trail leading to
Homo sapiens was not just a straight line, but was one of rich diversity.
Morphology
Typical of robust australopithecines,
P. robustus had a head shaped a bit like a
gorillaGorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...
's with a more massive built jaw and teeth in comparison to hominins within the
HomoHomo is the genus that includes modern humans and species closely related to them. The genus is estimated to be about 2.3 to 2.4 million years old, evolving from australopithecine ancestors with the appearance of Homo habilis....
lineage. The
sagittal crestA sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull of many mammalian and reptilian skulls, among others....
that runs from the top of the skull acts as an anchor for large chewing muscles. The DNH 7 skull of
Paranthropus robustus, "Eurydice", was discovered in 1994 at the Drimolen Cave in
Southern AfricaSouthern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
by
Andre KeyserAndre Werner Keyser , was a South African palaeontologist and geologist noted for his discovery of the Drimolen hominid site and of numerous hominid remains....
, and is dated to 2.3 million years old, possibly belonging to a female.
The teeth of these
primateA primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
s were larger and thicker than any gracile australopithecine found, due to the morphology differences Broom originally designated his find as
Australopithecus robustus. On the skull, a bony ridge is located above from the front to back indicating where the jaw muscles joined.
P. robustus males may have stood only 1.2m (4 feet) tall and weighed 54 kg (120 lb) while females stood just under 1 meter (3 feet 2 inches) tall and weighed only 40 kg (90 lb), indicating a large
sexual dimorphismSexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
. The teeth found on
P. robustus are almost as large as those of
P. boisei.
Broom analyzed his findings carefully and noted the differences in the molar teeth size which resembled a gorilla's a bit more than a human's. Other
P. robustus remains have been found in Southern Africa. The average brain size of
P. robustus measured to only 410 and 530 cc, about as large as a
chimpanzeeChimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
's. Some have argued that
P robustus had a diet of hard gritty foods such as nuts and tubers since they lived in open woodland and savanna. More recent research suggests that this taxon was more of a dietary generalist, and others have argued that they principally consumed hard and gritty resources as fallback foods only during time of nutritional stress.
A 2011 study using ratios of strontium isotopes in teeth suggested that
Australopithecus africanusAustralopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...
and
P. robustus groups in southern Africa were
patrilocalIn social anthropology, patrilocal residence or patrilocality is a term referring to the social system in which a married couple resides with or near the husband's parents. The concept of location may extend to a larger area such as a village, town, or clan area...
: females tended to settle farther from their region of birth than males did.
See also
External links