Despite a strong increase in the research on hominin percussive tool use, the primary focus in the study of technological behaviour still lies on flaked stone artefacts, especially for the Middle Palaeolithic. This paper aims to contribute to a more thorough understanding of the full spectrum of homi;nin technological behaviour, by presenting a systematic analysis of ground stone tools from the Last Interglacial Middle Palaeolithic site Neumark-Nord 2/2 (NN2/2) (Germany). At NN2/2, coarse gravel- and cobble-sized pieces (n = 351) were sourced from local outcrops of glacial deposits, with a preferential selection for quartzite and sandstone. Low-power use wear analysis and the archaeological context of these finds provide evidence for the possible use of at least 58 pieces for active (hammerstones) and 5 for passive (anvils) percussive tasks, specifically lithic production and potentially bone processing. These grounds stone tools are larger and heavier than the manuports. The hammerstones were preferentially made of quartz and quartzite, while the anvils are mostly of limestone. The limited build-up of use wear on the tools is interpreted as expedient use. The presence of post-depositional surface modifications, their relatively expedient use and their potential application on soft contact materials (e.g. nuts) resulted in a relatively low discernibility of the wear. With expediency being a key factor in Middle Palaeolithic lithic technology, we can expect comparable patterns for other similar-aged ground stone assemblages. Moreover, external factors, like geological context and raw material availability, post-depositional conditions and research focus and intensity, further contribute to the invisibility of such finds in the Middle Palaeolithic record.

The manufacture of geometric engravings is generally interpreted as indicative of modern cognition and behaviour. Key questions in the debate on the origin of such behaviour are whether this innovation is restricted to Homo sapiens, and whether it has a uniquely African origin1. Here we report on a fossil freshwater shell assemblage from the Hauptknochenschicht (‘main bone layer’) of Trinil (Java, Indonesia), the type locality of Homo erectus discovered by Eugène Dubois in 1891. In the Dubois collection (in the Naturalis museum, Leiden, The Netherlands) we found evidence for freshwater shellfish consumption by hominins, one unambiguous shell tool, and a shell with a geometric engraving. We dated sediment contained in the shells with 40Ar/39Ar and luminescence dating methods, obtaining a maximum age of 0.54 ± 0.10 million years and a minimum age of 0.43 ± 0.05 million years. This implies that the Trinil Hauptknochenschicht is younger than previously estimated. Together, our data indicate that the engraving was made by Homo erectus, and that it is considerably older than the oldest geometric engravings described so far. Although it is at present not possible to assess the function or meaning of the engraved shell, this discovery suggests that engraving abstract patterns was in the realm of Asian Homo erectus cognition and neuromotor control.