CCT NOA SUR   20418
CENTRO CIENTIFICO TECNOLOGICO CONICET NOA SUR
Centro Científico Tecnológico - CCT
congresos y reuniones científicas
Título:
Consumption of underground storage organs at Border Cave, South Africa, earlier than 100 000 years ago
Autor/es:
SIEVERS, C.; WADLEY, L.; BACKWELL, L.R.; D'ERRICO, F.
Lugar:
Johanesburgo
Reunión:
Conferencia; 21st conference of the Southern African Society for Quaternary Research (SASQUA); 2017
Institución organizadora:
University of the Witwatersrand
Resumen:
Fruits, nuts, seeds, wood and underground corms, tubers and rhizomes were necessities for hunter-gatherers during the Stone Age, yet they seldom preserve archaeologically in southern African Middle Stone Age (MSA) sites. Although it is generally charcoal from fires in hearths that is preserved, there are other and exception cases of plant preservation. Evidence from Sibudu implies that people were familiar with medicinal plants in the MSA (Wadley 2015) and at Boomplaas and Klasies River, burned plant material indicates that geophytes may have been cooked and eaten (Wadley 2015: 197). This interpretation is supported by finds of carbohydrate-rich corms at another MSA site, Strathalan Cave B (Wadley 2015). Here, we investigate evidence for much earlier use of underground storage organs (USOs), at Border Cave, South Africa. We describe the methods used in our investigations and the difficulty of making positive identifications, and we outline future strategies. Border Cave is in the Ingwavuma district of northern KwaZulu-Natal, on the border of Swaziland and South Africa. The cave has been extensively excavated in the past, but apart from a few preliminary plant identifications (Anderson 1978), little attention has until now been given to botanical remains from the site. An exception is the work on identifications of poison residues derived from plants younger than 40 000 years old (40 ka) (d?Errico et al. 2012). However, Border Cave occupations might have begun as early as 250 ka ago and the material from the 4 WA (White Ash) layers examined here have been dated by Electron Spin Resonance on tooth enamel to 115 ± 8, 113 ± 5 and 168 ± 5 ka (Grün et al. 2003). Fragments of vegetative parenchymatous tissue from plant parts such as roots, tubers, corms, bulbs and rhizomes (referred to as geophytes or USOs) are frequently not recognized in archaeobotanical assemblages. When they are recognized, they are identified according to external morphology, if it is preserved, and by internal anatomy (vascular tissue in particular) observed at high magnification under scanning electron microscopy (SEM). This combined approach was applied to the 22 USOs recovered from 4 WA. For the external morphological identification of the archaeological USOs, plant vouchers were consulted at Herbaria and modern plants were collected, charred and compared to the ancient samples. Size, shape, root position, surface features and detail visible under reflective magnification up to ×40, were recorded. These attributes, observed on 14 of the USOs, matched those of the rhizomes in the genus Tulbaghia, a monocotyledon belonging to the Alliaceae or onion family (Fig. 1). However, SEM examination of the vascular structure of modern and ancient material could not confirm the Tulbaghia identification and furthermore, it suggested that the ancient material resembled the rhizome of a dicotyledonous plant. We are thus faced with a conundrum, and much work ahead: in order to identify the early USOs at Border Cave we need to increase our reference collection of USOs to find a plant that matches both the morphology and the vascular tissue of the material from Border Cave. Even though we are not yet able to identify the remains to a specific genus or species, the presence of the USOs at Border Cave over 100 000 years ago makes a significant contribution to our knowledge about plant use at that time. The USOs would have been brought into the cave by humans and the intriguing questions are what they might have been used for and if processing by roasting, which likely caused their carbonization, was deliberate. REFERENCES ANDERSON, J. 1978. Provisional comments on fossil leaves and seeds from Border Cave. In: Beaumont, P.B. Border Cave, 518?530. Ph.D. thesis, University of Cape Town, Cape Town. D?ERRICO, F., BACKWELL, L., VILLA, P., DEGANO, I., LUCEJKO, J., BAMFORD, M.K., HIGHAM, T.F.G., COLOMBINI, M.P. & BEAUMONT, P.B. 2012. Early evidence of San material culture represented by organic artifacts from Border Cave, South Africa. Proceedings of the National Academy of Sciences of the United States of America 109(33), 13214?13219. GRÜN, R., P.B. BEAUMONT, P.V. TOBIAS & S.M. EGGINS. 2003. On the age of the Border Cave 5 human mandible. Journal of Human Evolution 45, 155?167. WADLEY, L. 2015. Those marvellous millennia: the Middle Stone Age of southern Africa. Azania: Archaeological Research in Africa 50(2), 155?226.