Thumbnail scrapers are, as the name suggests, very tiny. Usually they are retouched around the top and along the sides of the flake or a short blade. Although a limited number of such artifacts from Mesolithic sites have been recognized as important for wood working, most of them are of unknown function.
In Europe, scrapers of this type appeared to my knowledge first during the Aurignacian. Single examples are known for example from the Vezere rigion ( Abri Cellier). I personally know several examples from a surface scatter near the Monte Circeo 100 km south from Rome. The sizes of the Aurignacian tools from this area and probably some of their typological characteristics are partially attributable to local raw materials, which consist of small, heavily rolled pebbles of excellent flint seldom exceeding 10 cm in diameter. While Thumbnail scrapers are virtually absent in the European Aurignacian with better raw material resources, they are rather common in the Pontinian Aurignacian.
Thumbnail scrapers boomed during the late Magdalenian and are frequent during the Azilian /Federmesser ensembles. They remain important until the late Neolithic and even during the Bronze Age at some sites in N/W-Europe. In East and South Africa Thumbnail scrapers are common during the LSA, beginning with Enkapune Ya Muto rockshelter, Kenya, dated 35 to 40 k.a BP.
In Asia scrapers of this type play a role during the late Paleolithic until the Neolithic and are also present at multiple sites during early Holocene in Australia.
These examples show that a stray find of some of these tools can not be ascribed to a certain technocomplex. The thumbnail scrapers displayed here are from Wales and may belong to a Mesolithic /Neolithic horizon.