Is this comparable to the erectus' shell engraving c 0.5 Ma?
JCA Joordens cs 2015 Nature 518:228-231 doi 10.1038/nature13962
"Homo erectus at Trinil on Java used shells for tool production and engraving"
The manufacture of geometric engravings is generally interpreted as indicative of modern cognition & behaviour ... Here we report on a fossil fresh-water shell assemblage from the Hauptknochenschicht (HKS 'main bone layer'), type locality of H.erectus discovered by Eugène Dubois (1891). In the Dubois collection (Naturalis mus. Leiden NL) we found evidence for
- freshwater shellfish consumption by hominins,
- 1 unambiguous shell tool,
- a shell with a geometric engraving.
We dated sediment contained in the shells (40/39Ar, luminescence) ... max.age of 0.54 ± 0.10 Ma, min.0.43 ± 0.05 ... younger than previously estimated ... the engraving was made by Homo erectus ... considerably older than the oldest geometric engravings described so far ... engraving abstract patterns was in the realm of Asian H.erectus cognition & neuro-motor control.