Taung Child

Taung Child

Catalog number	Taung 1
Common name	Taung Child
Species	Australopithecus africanus
Age	About 2.8 mya and 3.3 years when deceased
Place discovered	Taung, South Africa
Date discovered	1924

The Taung Child (or Taung Baby) is the fossilised skull of a young Australopithecus africanus. It was discovered in 1924 by quarrymen working for the Northern Lime Company in Taung, South Africa. Raymond Dart described it as a new species in the journal Nature in 1925.

The Taung skull is in repository at the University of Witwatersrand. Dean Falk, a specialist in brain evolution, has called it "the most important anthropological fossil of the twentieth century."

History

Taung-1 front

In the early 20th century, the workers at limestone quarries in southern Africa routinely uncovered fossils from the tufa formations they mined. Many were of extinct fauna, which included baboons and other primates, and the more complete or somehow more interesting fossils were kept as curios by the Europeans that managed operations.

In 1924, workers at the Buxton Limeworks near Taung, South Africa, showed a fossilised primate skull to E. G. Izod, the visiting director of the Northern Lime Company, the managing company of the quarry. The director gave it to his son, Pat Izod, who displayed it on the mantle over the fireplace. When Josephine Salmons, a friend of the Izod family, paid a visit to Pat's home, she noticed the primate skull, identified it as from an extinct monkey, and realised its possible significance to her mentor, Raymond Dart.

Josephine Salmons was the first female student of Dart, an anatomist at the University of Witwatersrand. Salmons was permitted to take the fossilised skull and presented it to Dart, who also recognised it as a significant find. Dart asked the company to send any more interesting fossilised skulls that should be unearthed. When a consulting geologist named Robert Young paid a visit to the quarry office, the director, A. E. Speirs, presented him with a collection of fossilised primate skulls that had been gathered by a miner known as Mr. De Bruyn. Young sent some of the skulls back to Dart. When Dart examined the contents of the crate, he found a fossilised endocast of a skull, showing the impression of a complex brain, and matched it to a fossilised skull of a juvenile primate, which had a shallow face and fairly small teeth.

Only forty days after he first saw the fossil, Dart completed a paper that named the species of Australopithecus africanus – the "southern ape from Africa" – and described it as "an extinct race of apes intermediate between living anthropoids and man". The paper appeared in the 7 February 1925 issue of the journal Nature. The fossil was soon nicknamed the Taung Child.

Initial criticism of Dart's claims

Philip V. Tobias and the Taung Child.

Scientists were initially reluctant to accept that the Taung Child and the new genus Australopithecus were ancestral to modern humans. In the issue of Nature immediately following the one in which Dart's paper was published, several authorities in British paleoanthropology criticized Dart's conclusion. Dart's former mentor Arthur Keith, one of the most prominent anatomists of his time, claimed there was insufficient evidence to accept Dart's claim that Australopithecus was transitional between apes and humans. Grafton Elliot Smith stated that he needed more evidence – and a larger picture of the skull – before he could judge the significance of the new fossil. Arthur Smith Woodward dismissed the Taung Child as having "little bearing" on the issue of "whether the direct ancestors of man are to be sought in Asia or Africa".

These critiques became more fervent a few months later. Elliot Smith concluded that the Taung fossil was "essentially identical" to the skull of "the infant gorilla and chimpanzee" Addressing the claim that the fossil was "the missing link between ape and human", Arthur Keith stated in a letter to Nature that,

"an examination of the casts... will satisfy geologists that this claim is preposterous. The skull is that of a young anthropoid ape... and showing so many points of affinity with the two living African anthropoids, the gorilla and chimpanzee, that there cannot be a moment's hesitation in placing the fossil form in this living group".

"Far from the bones being objective facts to be judged as evidence, there was an established pattern of belief. There was a climate of opinion that favored discoveries made in Asia but not the 'silly notion' of small-brained bipeds from Africa."

Sherwood Washburn, "Human Evolution After Raymond Dart" (1985)

There were several reasons why it took decades for the field to accept Dart's claim that Australopithecus africanus was in the human line of descent. For one, the British scientific establishment was at the time enamored with the hoax Piltdown Man, which had a large brain and ape-like teeth. Expecting human ancestors to have evolved a large brain very early, they found that the Taung Child's small brain and human-like teeth made it an unlikely ancestor to modern humans. Until the 1940s, most anthropologists also believed that humans had evolved in Asia, not in Africa. And despite accepting that modern humans had emerged through evolution, a large number of anthropologists believed that the genus Homo had split from the great apes as much as 30 million years ago. They therefore felt uneasy about accepting that humans had had a small-brained, ape-like ancestor like Australopithecus africanus only two million years ago.

Solly Zuckerman, who had studied anatomy under Raymond Dart in South Africa, concluded as early as 1928 that Australopithecus was little more than an ape. He and a four-member team carried out further studies of the Australopithecine family in the 1940s and 1950s. Using a "metrical and statistical approach" that he thought was superior to purely descriptive methods, he decided that these creatures had not walked on two legs and were not an intermediate form between humans and apes. For the rest of his life, Zuckerman continued to deny that Australopithecus was part of the human family tree, even when this conclusion had become "universally accepted" by scientists.

Acceptance

File:Robert Broom00.jpg

Robert Broom, a Scottish doctor who became a professional paleontologist in 1933 at the age of sixty-seven, was for a long time one of Raymond Dart's only supporters. He himself discovered fossils of Australopithecus that contributed to the acceptance of Dart's interpretation of the Taung child as a transitional form between apes and modern humans.

Raymond Dart's claim that Australopithecus africanus – the species name he had given to the Taung Child – was a transitional form between apes and humans was at first almost universally rejected. Robert Broom, a Scottish doctor who worked in South Africa, was one of Dart's first – and for a long time one of his only – supporters. Two weeks after Dart announced the discovery of the Taung Child in Nature, Broom visited Dart in Johannesburg to see the fossil. After himself becoming a paleontologist in 1933, Robert Broom found adult fossils of Australopithecus africanus and discovered more robust fossils that were eventually renamed Australopithecus robustus.

In the late 1920s, American paleontologist William King Gregory also accepted that Australopithecus was part of the human family tree. Employed by the American Museum of Natural History in New York, Gregory supported Darwin and Huxley's then-unpopular view that humans were closely related to African apes. The director of the Museum, however, was Henry Fairfield Osborn, who despite being "the chief public defender of evolution in the United States" at the time of the Scopes Trial (1925), disagreed with Darwin's views on the origins of humanity. Gregory and Osborn repeatedly debated this issue in public forums, but Osborn's view that humans had evolved from early ancestors who did not look like apes prevailed among American anthropologists in the 1930s and 1940s. In 1938, Gregory visited South Africa and saw the Taung Child and the fossils Robert Broom had recently discovered. More convinced than ever that Dart and Broom were right, he called Australopithecus africanus "the missing link no longer missing".

The turning point in the acceptance of Dart's analysis of the Taung Child came in 1947, when the prominent British anthropologist Wilfrid Le Gros Clark announced that he supported it. Le Gros Clark, who would also play an important role in exposing the Piltdown fraud in 1953, visited Johannesburg in late 1946 to study Dart's Taung skull and Broom's adult fossils with the intention of proving that they were only apes. But after two weeks of studies and after visiting the caves where Broom had found his fossils – the Taung cave had been destroyed by miners soon after the discovery of the Taung skull – Le Gros Clark became convinced that "Dart and Broom were essentially right in their assessment of the significance of the australopithecines as the probable precursors of more advanced types of [humans]." In early January 1947 at the First Pan-African Congress on Prehistory, he was the first anthropologist of such stature to call the Taung Child a "hominid", that is, an early human. An anonymous article published in Nature on 15 February 1947 announced Le Gros Clark's conclusions to a wider public. On that day, Arthur Keith, who had been one of Dart's most virulent critics, composed a letter to the editor of Nature announcing that he supported Le Gros Clark's analysis: "I was one of those who took the point of view that when the adult form [of Australopithecus] was discovered it would prove to be near akin to the living African anthropoids—the gorilla and the chimpanzee. I am now convinced ... that Prof. Dart was right and that I was wrong." As Roger Lewin put it in his book Bones of Contention, "a prompter and more thorough capitulation could hardly be imagined."

Identification

Taung child – Recovering the missing parts of skull by Arc-Team, Antrocon NPO, Cicero Moraes, University of Padua

File:Taun child - Facial forensic reconstruction.png

Taung child – Facial forensic reconstruction by Arc-Team, Antrocon NPO, Cicero Moraes, University of Padua

Raymond Dart "drew bold conclusions from his unavoidably limited observations" The idea that the skull belonged to a new genus was identified by comparison with skulls of chimpanzees. The endocast of the Taung child was larger than a fully grown chimpanzee's. The forehead of the chimpanzee receded to form a heavy browridge and a jutting jaw; while the Taung child's forehead recedes, but leaves no browridge. The Taung child's foramen magnum (a void in the cranium where the spinal cord is continuous with the brain) is located beneath the cranium, showing that the creature stood upright.

Dean Falk, a specialist in neuroanatomy, noted that Dart had not fully considered certain apelike attributes for Taung.

"In his 1925 article, Dart had claimed that the brain of Taung was humanlike. As it turned out, he was wrong about that. . . . Taung's humanlike features were overemphasized".

"Like humans, other primates go through stages as they grow up. In his analysis of Taung, Dart did not fully appreciate that infant apes have not had time to develop features of the skull, such as thickened eyebrow ridges or attachment areas for heavy neck muscles, that set adult apes apart from human. Apparently he did not carefully consider the possibility that Taung's rounded forehead or the inferred position of the spinal cord might be due to the immaturity of the apelike specimen rather than to its resemblance to humans".

Subsequently, Falk unearthed an unpublished manuscript that Dart completed in 1929 in the Archives of the University of Witwatersrand, which provides a much more thorough description and analysis of the Taung endocast than Dart’s earlier announcement in Nature. Whereas Dart had identified only two potential sulci on the Taung endocast in 1925, he identified and illustrated 14 additional sulci in this still unpublished monograph. There, too, Dart detailed how Taung’s endocast was expanded globally in three different regions, contrary to the suggestion that he believed hominin brains evolved back-end-first, i.e., in a so-called mosaic fashion. Recently, Falk described the frontal-lobe sulcal pattern on the Taung and other australopithecine endocasts, which is derived toward a humanlike pattern compared to that of apes.

Description

The fossil consists of most of the face and mandible with teeth, and, uniquely, a natural endocast of the braincase. It is estimated to be 2.5 million years old. Originally thought to have belonged to a monkey or ape, the skull, as Dart realised, must have been positioned directly above the spine, indicating an upright posture. This is a trait seen in humans, but unknown in other primates.

The Taung Child was originally thought to have been about six years old at death, because of the presence of deciduous teeth; but it is now believed to have been about three or four, based on studies of rates of enamel deposition on the teeth. The creature stood 105 centimetres (3 ft 5 in) tall and weighed between 9 and 11 kilograms (20 and 24 lb). It had a cranial capacity of 400–500 cc, and lived mainly in a savanna habitat.

Comparison of the Taung Child fossil to the skull of a nine-year-old modern child suggest that A. africanus had a growth rate to adolescence more similar to that of modern apes, like chimpanzees (genus Pan), than to that of modern Homo sapiens.

The Taung Child probably was killed by an eagle or other large predatory bird, judging by the similarity of damage to the skull and eye sockets of the Taung Child to that seen in modern primates known to have been killed by eagles.

See also

• Selam (Australopithecus)
• List of human evolution fossils
• List of fossil sites

External links

• Maropeng – The Cradle of Humankind Official Website
• Downloadable 30 minute analysis by the BBC
• NPR Radiolab podcast about the Taung Child (also contains some ancillary material)