Fossils and the evidence they provide: the tale of SK 54 and SK 349.
By Dr Mirriam Tawane, Curator Palaeontology, DITSONG: National Museum of Natural History
Fossils are regarded as heritage and scientific objects. Most are discovered in a fragmentary manner, while others are perfectly complete. Sometimes the completeness of the specimen assists in the excitement visitors experience when viewing a specimen. The near perfect preservation of these adds to the awe responses from those viewing the specimen.
Narrating any information about the specimen is exciting when there is plenty to share, and of course plenty to see. Visuals have always been helpful during a learning experience. Fossilised bones could preserve on them some evidence of what could have happened to them, or any environmental conditions they might have been exposed to. Tooth marks are not abundant in the fossil record, and when preserved they could shed light on the predator-prey relationship the animals might have been subjected to.
SK 54 is one of those specimens that are almost near complete, and it preserves a very interesting story. Visitors are always fascinated by its preservation, and the story that comes with it. It is a fossilised cranium of a juvenile Paranthropus robustus discovered at Swartkrans in 1949. SK 54 consists of the left and right side of the parietal bones, the frontal and occipital bones. It was discovered by Robert Broom and John Robinson (also the discoverers of Plesianthropus transvaalensis (now Australopithecus africanus), popularly called Mrs Ples). It dated between 1.8 and 1.3 million years old. The cranium preserves two puncture marks on the two sides of the parietals. Bob Brain (a former director of the Transvaal Museum, now DNMNH) studied the marks, and hypothesised that they were created by pointed objects, with slightly diverging tips. The puncture marks are 33 mm apart (fig 2).
Figure 1: Picture of Paranthropus robustus, SK 54 showing the puncture marks caused by the lower canines of the leopard.
It is likely that the carnivore which could have possibly caused the punctures is a leopard; scientific name Panthera pardus. A lower jaw of Panthera pardus labelled SK 349 (fig 2), was discovered in the same deposits where SK 54 was discovered. The spacing of the puncture marks on SK 52 matches the spacing of the lower canines of SK 349.
Figure 2: Picture of the lower jaw of Panthera pardus, SK 349.
The damage to the skull of Paranthropus robustus could have been caused when the leopard picked up the head of the juvenile it had killed and dragged it to a feeding place. The lower canines of the leopard appear to have punctured the parietals; while the upper canines pierced through the hominid’s face. This is illustrated in the reconstruction in figure 3. The damage might not be done by this particular specimen found within the same deposits, but by an animal with the same morphology, one belonging to the same group.
Figure 3: The reconstruction of how the puncture marks on SK 54 could be explained (From Brain, 1970).
SK 54 and SK 349 tell a fascinating tale. They may serve as evidence of an event that happened in the distant past; information that is very valuable considering the fractured nature of fossils and the many unanswered questions that usually accompany most of the discoveries.
References
- Brain. C. K. 1970. New finds at the Swartkrans Australopithecine site. Nature. (London). 225(5238): 1112-1119.
- Brain. C. K. 1981. The hunters or the hunted. An introduction to African cave taphonomy. The University of Chicago Press.
