Diacritic schemes showing the directionality of the dorsal and ventral removals on the Nubian core sample from Al-Kharj 22.

<p>Diacritic schemes showing the directionality of the dorsal and ventral removals on the Nubian core sample from Al-Kharj 22.</p

Nubian preferential Levallois cores from Al-Kharj 22.

<p>Drawings by G. Devilder, CNRS.</p

Topographic map of the Al-Kharj region in central Saudi Arabia.

<p>Spots are showing archaeological sites discovered during the 2011 survey activities. Map by J. Schiettecatte, CNRS.</p

Diacritic schemes showing the directionality of the dorsal and ventral removals on the Nubian core sample from Al-Kharj 22.

<p>Diacritic schemes showing the directionality of the dorsal and ventral removals on the Nubian core sample from Al-Kharj 22.</p

Distribution of main sites with Nubian cores in Eastern Africa and Arabia.

<p>Illustrated cores do not represent actual size. 1. Al-Kharj 22 (this study); 2. Aybut Al Auwal <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Rose5" target="_blank">[12]</a>; 3. Shabwa <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Inizan2" target="_blank">[30]</a>; 4. Hadramawt <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Crassard1" target="_blank">[5]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Crassard2" target="_blank">[6]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Crassard3" target="_blank">[27]</a>; 5. Aduma <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Yellen1" target="_blank">[112]</a>; 6. Gademotta <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Wendorf1" target="_blank">[113]</a>; 7. Asfet <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Beyin2" target="_blank">[114]</a>; 8. Nazlet Khater 1 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Vermeersch1" target="_blank">[115]</a>; 9. Abydos <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069221#pone.0069221-Chiotti1" target="_blank">[66]</a>.</p

Nubian preferential Levallois cores from Al-Kharj 22.

<p>Drawings by G. Devilder, CNRS.</p

Survey activities undertaken in 2011.

<p>In the proximity of the modern town of Al-Kharj, with the discovered Middle Paleolithic surface scatters, including Al-Kharj 22 site. Map by J. Schiettecatte, CNRS.</p

Al-Kharj 22 site.

<p>A: topographic map with isolines, the grey area within the plot indicates the extent of the surface scatter; B: orographic map with slightly exaggerated reliefs; C: panoramic view of the site from the South-West.</p

Total artifact counts for the Al-Kharj 22 collection sample.

<p>Total artifact counts for the Al-Kharj 22 collection sample.</p

Schematic representation depicting the three main dorsal preparation types, preparation type 1, 2 and 1/2, and the proposed reduction succession discussed in the text.

<p>In order to facilitate comprehension cores, end-products and preparation by-products have been color-coded; blue equals type 1 preparation, green type 2 and yellow type 1/2.</p