Shell markings are the oldest abstract signs ever discovered
A zigzag engraving on a shell from Indonesia is the oldest abstract marking ever found. But what is most surprising about the half-a-million-year-old doodle is its likely creator - the human ancestor Homo erectus.
By 40,000 years ago, and probably much earlier, anatomically modern humans - Homo sapiens - were painting on cave walls in places as far apart as Europe and Indonesia. Simpler ochre engravings found in South Africa date to 100,000 years ago. Earlier this year, researchers reported a 'hashtag' engraving in a Gibraltar cave once inhabited by Neanderthals. That was the first evidence for drawing in any extinct species.
http://www.nature.com/news/neanderthals-made-some-of-europe-s-oldest-art-1.15805
But until the discovery of the shell engraving, nothing approximating art has been ascribed to Homo erectus. http://en.wikipedia.org/wiki/Homo_erectus
The species emerged in Africa about 2 million years ago and trekked as far as the Indonesian island of Java, before going extinct around 140,000 years ago. Most palaeoanthropologists consider the species to be the direct ancestor of both humans and Neanderthals.