Palaeoproteomics confirm earliest domesticated sheep in southern Africa ca. 2000 BP

Ashley N Coutu,Theis Zetner Trolle Jensen,Matthew J Collins,Alberto J Taurozzi,Meaghan Mackie,Judith Sealy

doi:10.1038/s41598-021-85756-8

Abstract

We used palaeoproteomics and peptide mass fingerprinting to obtain secure species identifications of key specimens of early domesticated fauna from South Africa, dating to ca. 2000 BP. It can be difficult to distinguish fragmentary remains of early domesticates (sheep) from similar-sized local wild bovids (grey duiker, grey rhebok, springbok—southern Africa lacks wild sheep) based on morphology alone. Our analysis revealed a Zooarchaeology by Mass Spectrometry (ZooMS) marker (m/z 1532) present in wild bovids and we demonstrate through LC–MS/MS that it is capable of discriminating between wild bovids and caprine domesticates. We confirm that the Spoegrivier specimen dated to 2105 ± 65 BP is indeed a sheep. This is the earliest directly dated evidence of domesticated animals in southern Africa. As well as the traditional method of analysing bone fragments, we show the utility of minimally destructive sampling methods such as PVC eraser and polishing films for successful ZooMS identification. We also show that collagen extracted more than 25 years ago for the purpose of radiocarbon dating can yield successful ZooMS identification. Our study demonstrates the importance of developing appropriate regional frameworks of comparison for future research using ZooMS as a method of biomolecular species identification.

Highlights

The transition from hunting and gathering to food production is one of the most important processes in human history
Zooarchaeology by Mass Spectrometry (ZooMS) has been used to identify animal species from which bone was selected to fashion into a rtefacts[33], to distinguish East African sheep and g oats[2], to identify Asian fauna moving into eastern Africa[30], and to investigate early farmers’ choice of elephant or hippo ivory in south-eastern Africa[34]
The aims of this research were, (1) to identify ZooMS peptide markers capable of distinguishing sheep from wild south-west African bovids of similar size and morphology, (2) to search for these markers in faunal remains believed to be those of domesticated sheep, especially the earliest directly dated sheep specimen in southern Africa, from Spoegrivier, and (3) to assess the viability of minimally destructive collagen extraction for archaeological samples from these contexts

Summary

Introduction

The transition from hunting and gathering to food production is one of the most important processes in human history. The archaeological bones included in this study were originally identified as sheep by faunal expert Richard Klein, based on morphological criteria These specimens were selected jointly by Richard Klein, Royden Yates and Judith Sealy for AMS radiocarbon dating to begin to establish a more secure chronology for the introduction of domesticated stock into southern Africa based on direct AMS dates rather than dating by association[7, 8]. A key criterion for selection was the choice of skeletal elements most clearly diagnostic of sheep, as opposed to wild species These specimens are unlikely to be goats, since domesticated goats have not been recorded from precolonial times in south-western South Africa, they were present in the northern and eastern parts of the country[5, 25]. Springbok Springbok Springbok Grey rhebok Zulu sheep Namaqua Afrikaner sheep Damara sheep Namaqua Afrikaner sheep Mbuzi veld goat

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