Spotlight on Students: Hominid Profiles

The following post is another spotlight on students featuring the work of one of my students enrolled in my Anthropology 102: Introduction to Physical Anthropology courses.  The students were tasked with providing a comprehensive summary of a hominid of their choice, and this is one of the exemplary works.  Be prepared to learn about hominids and human evolution.

Ms. Ples (Diagnostic adult Australopithecus africanus): Transvaal Museum, Pretoria, South Africa

 Australopithecus africanus
By Esmeralda Salas, Anth 102: 1501

Each discovery of hominid species brings with it a better understanding of modern human origins.  In the case of Raymond Dart’s discovery in the early 1920s, findings can provide irrefutable information about where humans evolved.  Before delving into a review of Australopithecus africanus, it is important to have some historical context in order to appreciate its importance in relation to human evolution.

Since the publication of Charles Darwin’s The Descent of Man in 1871, the scientific community was aware of the idea that it was “more probable that our early progenitors lived on the African continent than elsewhere” (Darwin, 191).  Many at the time, however, believed that early humans had evolved in Europe or Asia; a belief supported by the 1912 discovery of Piltdown Man of England. It would take nearly three decades since Dart’s discovery for Pildown Man to be exposed as a hoax.  This was also the same amount of time that it took for Dart’s claims to be justified.  Raymond Dart revolutionized the idea of human evolution and provided evidence for Darwin’s claims with the examination of a fossil skull, Taung Child that he had obtained from a quarry in Taung, South Africa (Wayman).  What he had in his hands that autumn of 1924 was the first Australopithecine discovered; its namesake meaning “southern ape from Africa.”

Australopithecus africanus is an amalgamation of ape and human features.  According to the Smithsonian Institution, this species lived approximate 3.3 to 2.1 million years ago.  The overall size of the body shows a degree of sexual dimorphism as males are estimated to weigh about 41 kilograms and measure 138 centimeters in height, while females are estimated at 66 kilograms and 115 centimeters (Australopithecus africanus).  Significantly smaller than a modern human, Australopithecus africanus has other diminutive features.   The skull approximates human features, but it also reveals how much development of the brain occurred since this species.  The cranial skeleton reveals a brain case of approximately 450-550 cc, a rounded vault lacking cranial crests, and a less prognathic face (Stanford, Allen, and Anton, 261).   This comes in contrast to modern human brain capacity. 

Much of the diet Australopithecus africanus ingested is inferred by dental characteristics.  The large, more developed front teeth and range of motion of the jaw “were important in food processing, e.g., husking, stripping, nipping, and cutting” (Sarmiento, Sawyer, and Milner, 96).   Studies have also been made that reveal some the possible foods that were consumed.  Enamel micro-ware analyses suggest food consumed by Australopithecus africanus resembled that of modern chimpanzees; however unlike these apes, they displayed an ability only unique to humans (Sarmiento, Sawyer, and Milner, 96).  

Perhaps most notable is the position of the foramen magnum, which is situated toward the front of the skull and oriented downward (Australopithecus africanus).  This is an important attribute because it is what suggests bipedal locomotion in this species and is evidence of an ancestral link to humans.   Other fossils of this kind have demonstrated skeletal structures that support bipedal locomotive pattern.  STS 14, discovered by Robert Broom and John T. Robinson in  Sterkfontain, South Africa, in 1947, is an incomplete skeleton consisting of several thoracic and lumbar vertebrae, a pelvis, a sacrum, and pieces of a rib and a femur (STS 14). This small-bodied creature had the ability to walk on two feet as the vertebrae of the spine had a distinctive shock absorbing curvature characteristic of other bipedal vertebrates (STS 14).   

It is important to note that other bones of Australopithecus africanus imply another element to its locomotive pattern.  A study by David Green and Adam Gordon looked at different fingers of the hand, specifically a distinct curvature of the phalanges.  What they concluded “suggests that arboreality would have been a significant component of their regime” (Green and Gordon, 718).   This characteristic again reinforces the link between human and ape.

The discovery Taung Child is an important contribution that steered human knowledge toward the right path, despite having been overlooked at the beginning.  Raymond Dart and those after him have enhanced the understanding of what it means to be human. Though Australopithecus africanus alone does not provide all the answers about human evolution, it does represent an important branch of the hominin family tree. 

Works Cited

"Australopithecus Africanus." Australopithecus Africanus. Smithsonian Institution, n.d. Web. 17

 Apr. 2014.

Darwin, Charles. "Affinities and Geneology." The Descent of Man, and Selection in Relation to

            Sex. London: John Murray, 1871. 191. Print.

Green, David J., and Adam D. Gordon. "Metacarpal Proportions in Australopithecus Africanus."             Journal of Human Evolution 54.5 (2008): 718. Print.

Sarmiento, Esteban E., G. J. Sawyer, Richard Milner, Viktor Deak, and Ian Tattersall. "The          South African Fossil Cave Sites." The Last Human: A Guide to Twenty-Two Species of   Extinct Humans. New Haven, CT: Yale UP, 2007. 96. Print.

Stanford, Craig B., John S. Allen, and Susan C. Antón. "Early Hominins and Australopithecus."

            Exploring Biological Anthropology: The Essentials. 3rd ed. Boston: Pearson, 2013. 261.

            Print.

"STS 14." Human Evolution by The Smithsonian Institution's Human Origins Program.     Smithsonian Institution, n.d. Web. 18 Apr. 2014.

Wayman, Erin. "How Africa Became the Cradle of Humankind." Smithsonian. Smithsonian

            Institution, 17 Oct. 2011. Web. 18 Apr. 2014.