Etchings on a 500,000-year-old shell appear to have been made by human ancestor

Dec 4, 2014

WIM LUSTENHOUWER/VU UNIVERSITY AMSTERDAM

By Michael Balter

In 2007, Stephen Munro got the shock of his life. The archaeology graduate student was studying mollusk shells gathered more than 100 years ago on the Indonesian island of Java, where an early human ancestor, Homo erectus, had roamed at least 1 million years ago. As he studied photographs of the shells, Munro spotted one apparently engraved with a pattern of zigzag lines. “I almost fell off my chair,” he says. That’s because the oldest known engravings date back 100,000 years and were made by modern humans—the only species thought to be capable of making abstract designs.

Now, after 7 years of work on the shells, Munro and colleagues have confirmed their observations. They also report that one of the shells was used as a tool of some sort, a finding that would expand the known toolmaking capabilities of H. erectus, which was thought to have made only simple tools out of stone.

“If correct it certainly pushes back in time the evidence for marking objects in a way that arguably could be considered evidence for symbolic activity,” says Curtis Marean, an archaeologist at Arizona State University, Tempe, who was not involved in the study. But he points out that the Java site, known as Trinil, was excavated in the 1890s using “quite primitive” archaeological methods and that no one has reexamined the location using modern techniques. That means, he says, that “the observation is essentially devoid of context.”

Mindful of this kind of criticism, archaeologist and team leader Josephine Joordens of Leiden University in the Netherlands says her group took its time answering a series of questions about how the shell came to be engraved as well as when it might have happened. First, the researchers looked at how the shells accumulated at Trinil in the first place. Munro had focused his research on about 166 specimens of the freshwater mollusk Pseudodon, collected by Dutch paleoanthropologist Eugène Dubois at the site where he found now-famous H. erectus fossils. Studying cigar boxes full of mollusks from the site that are now housed in Leiden, Joordens and other team members found that a third of the shells had holes right where a muscle that keeps the shell closed is found. These holes were apparently made by humans using shark teeth, also found at the site, as tools to open the shells so they could eat them; when team members did their own experiments trying to open shells with sharks’ teeth, they got a very similar pattern of holes.


Read the full article by clicking the name of the source located below.

20 comments on “Etchings on a 500,000-year-old shell appear to have been made by human ancestor

  • But not exactly starting a line where another ends. These are intentional marks, maybe discovering the strikingly powerful effect of lines on our visual system.

    Our edge detectors are some of the lowest level hypotheses our brain makes. They came about as a staging post visual inference to identifying a discrete object. Reification is the very root of cognition and edge detection its primary building block.

    Note- edge detection didn’t evolve for line detection. Very few lines exist in the natural world. So this discovery of lines with a strong (effectively aesthetic) effect on our edge detectors seem to connote significance (but why???). This must have been oddly troubling.

    Like the zig zags on the pottery posted recently, these zig zag lines are wired into our brain. We migraineurs see them often.



    Report abuse

  • @OP –

    Studying cigar boxes full of mollusks from the site that are now housed in Leiden, Joordens and other team members found that a third of the shells had holes right where a muscle that keeps the shell closed is found. These holes were apparently made by humans using shark teeth, also found at the site, as tools to open the shells so they could eat them; when team members did their own experiments trying to open shells with sharks’ teeth, they got a very similar pattern of holes.

    While this pushes back the history of tool use by Homo species, we should not be too surprised, considering that Capuchins, Chimps and some birds use tools. Pattern carving is one step further.



    Report abuse

  • I cant see how they can date markings . Obviously they are provably pre-modern but surely a million year old artefact can have 1000 year old markings .



    Report abuse

  • hardy Dec 5, 2014 at 8:55 am

    I cant see how they can date markings . Obviously they are provably pre-modern but surely a million year old artefact can have 1000 year old markings .

    Usually archaeologists would use datable undisturbed layers of material above or in which the exhibits were found or date the material its self if it was a suitable material.

    @OP link – .” But the detailed studies of the engraving, the team reports online today in Nature, revealed that the interiors of the grooves were smooth and rounded, compared with the “jagged and sharp-edged” grooves that team members made themselves on ancient Pseudodon shells. That’s a telltale sign that weathering of the engraving had taken place after the shells were buried in sediments at the Trinil site. Dennell is persuaded. “That part of the analysis is water-tight,” he says.

    The shells show signs of being buried after the carving was done, but there is uncertainty in linking them to the Homo erectus.

    @OP link- Although the team dated four of the shells in the collection, including the engraved shell, to about 500,000 years ago using two different techniques on sediments of sand and clay found inside them, Ciochon says that those sediments could have entered the shells during the earlier flood event that created the site, and that H. sapiens still could have come along much later and performed the etching.

    So far, of course, there is only one example of such a potentially ancient engraving to study. But now that it has been found, Joordens says, she hopes that other researchers will search their own collections for other samples.



    Report abuse

  • I would argue that edge detectors might have evolutionary value. Horizontal edges and fairly straight ones in particular. For example the straight edge produced by a deer’s back when standing in the forest, makes it more easily discerned from surrounding flora.



    Report abuse

  • This could be the first known”signature” A making to identify who owned that tool. Just a thought. Or it could be doodling like modern humans do when bored or while thinking. When I doodle I generally do some sort of zig zag pattern.Making zig zags is a very basic form for a simpler mind compared to O or other shapes. Scratching shapes into hard objects would lead to simple lines where a being would just have to draw the etching tool across the object



    Report abuse

  • Edge detection is hugely useful. A sufficiently closed set of edge detections (they work as little line segments like the polylines in my CAD system) may trigger the next inference level up in defining an object.

    I was arguing line detection (as in actual 2D line detection) was much less useful given the paucity of lines in nature. Your example of actual 2D lines is a good one, though. Edge detection, however, will have started its evolution perhaps over 400 million years ago. Detection of objects as objects will have been needed when good enough image forming eyes were created. Stripes probably wouldn’t have developed on sexually reproducing mammals were it not for edge detection already being in place.



    Report abuse

  • I would imagine touch would have happened before imaging vision. I think the aversive receptors heat and noxiceptors (nasty chemicals) would be the first to evolve, though I guess nice chemicals are just as needed.

    The nicest nerves are the C-tactile fibres that mammals have. These are dedicated to pleasure, only recently found and start wherever there is hair/fur and terminate in the basal gandlia. These are a trigger for oxytocin flow and typically are activated during grooming. Hair/fur acts as a mechanical amplifier (well transformer/lever) gathering the lightest of pressures. The residuum of body hair we retain may have some reproductive purpose…

    These clearly arrived much later on the scene with the advent of oxytocin and fur…..though thinking about it…there are other pleasurable chemicals and there are feathers. Might dinosaurs have groomed? Er no. Birds don’t mutually groom.

    Echlocation of any sophistication depends on carefully sculpted sounds and acute hearing. I suspect this duo needs even more evolutionary development time than sight. It is certainly much less common than sight.



    Report abuse

  • Interesting comment Phil, I’ve worked with computer vision; giving software the ability to recognise text or objects. One of the first things to overcome in this field is edge detection, it seems this is at the heart of visual perception be it artificial or natural.

    Current edge detection methods in computer vision are pretty accurate but it comes at a cost – the algorithms are costly in terms of processing power, for a computer to ‘read’ say a list of 10 sentences it would take roughly 2 minutes with 90-95% accuracy.

    The calculations to do the same in nature must come at a fraction of that time, I presume that would be due to fierce selection criteria in nature starting at the point the eye could see varying wavelength and depth.



    Report abuse

Leave a Reply

View our comment policy.