The expansion of later Acheulean hominins into the Arabian Peninsula

Abstract

The Acheulean is the longest lasting cultural-technological tradition in human evolutionary history. However, considerable gaps remain in understanding the chronology and geographical distribution of Acheulean hominins. We present the first chronometrically dated Acheulean site from the Arabian Peninsula, a vast and poorly known region that forms more than half of Southwest Asia. Results show that Acheulean hominin occupation expanded along hydrological networks into the heart of Arabia from Marine Isotope Stage (MIS) 7 until at least ~190 ka ̶ the youngest documented Acheulean in Southwest Asia. The site of Saffaqah features Acheulean technology, characterized by large flakes, handaxes and cleavers, similar to Acheulean assemblages in Africa. These findings reveal a climatically-mediated later Acheulean expansion into a poorly known region, amplifying the documented diversity of Middle Pleistocene hominin behaviour across the Old World and elaborating the terminal archaic landscape encountered by our species as they dispersed out of Africa.

Figure 1

Map showing locations of major river systems and Arabian sites noted in text (a); view of surrounding plain from the top of the andesite dyke: Trench 1 excavations are to the left of the jeeps (b).

Figure 2

Analysis of the artefact distributions within Trench 1 combining Whalen’s 3D artefact co-ordinates with the newly recorded stratigraphy showing (a) distribution of artefacts split by raw material types. (b) Hot-Spot analysis of gross artefact volume (L × W × T) indicating concentrations of significantly high and low artefact volumes; (c) total artefact densities. Filled black circles represent the locations of sediment samples for luminescence dating. Modified from Shipton and colleagues.

Figure 3

Stratigraphy of Saffaqah, determined from new excavations with sediment samples for luminescence dating bracketing Layer E. Modified from Shipton and colleagues.

Figure 4

Composite figure of lithics from Saffaqah Layer E, (a) large flake with eraillure flake still attached; (b) large flakes; (c) typical handaxe; (d) giant andesite core. Modified from Shipton and colleagues.

Figure 5

Kernel density estimate of the pIRIR₂₉₀ (blue) and RF₇₀ (red) equivalent doses (dots) and associated error bars in ascending order. The boxplot shows the distribution parameters (median as bold line, box delimited by the first and third quartile, whiskers defined by the extremes).The plot was obtained from the R (R Development Core Team, 2015) package ‘Luminescence’ version 0.8.2^–.