Paranthropus - Wiki Commons
One very intriguing question in our understanding of hominin evolution is the relationship between two groups of species.
Most palaeoanthropologists consider the robust australopithecines to be an offshoot of the gracile australopithecines and most are in agreement that the former deserve a separate genus – Paranthropus. This is currently up for debate because we now realise that there could be more to hominin evolution on the African continent than the fossil record is leading us to believe.
Palaeoanthropologists have focused primarily upon the structure of primarily the skulls that have been attributed to the paranthropines. The robust nature of these has provided such a draw to researchers, but today science has diversified and there is more communication taking place between disciplines leading to a more round understanding of these intriguing creatures. One of the latest papers on the paranthropines, investigates the diet of early Homo and Paranthropus.
Robust Australopithecines (Also known as Paranthropus)
Gracile Australopithecines (Also known as Australopithecus)
The remaining part of this article will now look at our understanding of other species that lived contemporaneously with the paranthropines, focusing upon the results of a paper published in 2012.
Homo was understood to be a hominin who availed of multiple resources from meat to vegetation and by extension led one of the most successful genera in the planets history. On the other hand Paranthropus was a specialist in the consumption of vegetation and went the way of the gradual extinction route. This was the understanding but more methods of getting the evidence necessary to support such a claim has open the door on other possibilities.
Laser ablation analysis can help us understand the diet of an individual in the context of the changing environment in which it lives. This is rather important and moves away from the comparison between specimens. If we understand the environment of Specimen T, for example and if we find the other specimens with a similar environment, then we can attempt to compare individuals. The paper sets out to try and see habitat changes through the teeth of a sample of specimens.
Early Homo, Australopithecines, Paranthropines and early cattle (both Browsers and Grazers) were compared using laser ablation of the ratios of strontium to strontium, strontium to calcium and barium to calcium isotopes. Isotopes are atoms of the same element with different mass numbers due to the differing number of neutrons in the nucleus. Low Barium: Calcium ratios are generally present in carnivores, while high Strontium or Barium: Calcium ratios are present in grazers. Strontium is picked up by the grazer and the grazer could become prey to the carnivore leaving traces in the teeth for the laser ablation to detect.
The species A. africanus had a diet which comprised meat, tree leaves and fruit and could have been eaten on a seasonal scale. This gives some support to the Resource Fallback hypothesis suggesting that hominins ate more common less nutritious foods as more preferred foods became rare. In the case of A. africanus it is not possible to tell of they fell back upon meat or woody plants.
P. robustus had a diet focused upon woody plant materials lacking the diversity of A. africanus, evident from the indistinguishable nature of the various ratios of this species and browsing cattle contemporaneous with these hominins.
Early Homo relied heavily upon meat resources when compared to the above species.
The team point out that Australopithecus sediba needs to be tested using laser ablation.
What makes the scientific discipline of Palaeoanthropology so fascinating is the many competing hypotheses that are proposed. The evidence from the fossils are going some way to helping us understand the environmental change that took place around 2 million years ago (Ma). This is what makes it one of the freshest of the sciences. Viva Palaeoanthropology!
If your interest has been sparked, then check out the paper, which was published in the journal Nature.
Written by Charles T. G. Clarke
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