Using plant microfossils from dental calculus to recover human diet: a case study from Tell al-Raqā'i,Syria

Dietary reconstructions based on plant microfossils, such as starch grains and phytoliths, have been useful in increasing our understanding of past human populations. Microfossils have been recovered from sediments, stone tools, and, more recently, dental calculus. Methods for recovering microfossils from dental calculus have yet to be firmly established and there is some question about potential damage to the teeth. Using a sample of teeth from the middle Holocene site of Tell al-Raqā'i, Syria, we tested using a dental pick to sample the calculus. ESEM images taken before and after sampling show no damage to the enamel surface, and examination of the recovered microfossils show that this method provides ample material for study, even when not all of the calculus is removed from the tooth. Preliminary identification of the plant microfossils suggests that these individuals were consuming a variety of plant foods, but that domesticated cereals such as wheat and barley made up a surprisingly small portion of their diet.     

Evaluating microfossil content of dental calculus from Brazilian sambaquis

To date, limited numbers of dental calculus samples have been analyzed by researchers in diverse parts of the world. The combined analyses of these have provided some general guidelines for the analysis of calculus that is non-destructive to archaeological teeth. There is still a need for a quantitative study of large numbers of calculus samples to establish protocols, assess the level of contamination, evaluate the quantity of microfossils in dental calculus, and to compare analysis results with the literature concerning the biology of calculus formation. We analyzed dental calculus from 53 teeth from four Brazilian sambaquis. Sambaquis are the shell-mounds that were established prehistorically along the Brazilian coast. The analysis of sambaqui dental calculi shows that there are relatively high concentrations of microfossils (phytoliths and starch), mineral fragments, and charcoal in dental calculus. Mineral fragments and charcoal are possibly contaminants. The largest dental calculi have the lowest concentrations of microfossils. Biologically, this is explained by individual variation in calculus formation between people. Importantly, starch is ubiquitous in dental calculus. The starch and phytoliths show that certainly Dioscorea (yam) and Araucaria angustifolia (Paraná pine) were eaten by sambaqui people. Araceae (arum family), Ipomoea batatas (sweet potato) and Zea mays (maize) were probably in their diet.     

基于人牙结石的淀粉粒证据探讨裴李岗遗址先民植物性食物来源

人牙结石淀粉粒分析是开展古代居民食物来源研究的有效途径之一。用此方法对河南新郑裴李岗遗址仅存的两具裴李岗文化人骨牙齿上的结石开展了淀粉粒分析,成功提取出38颗淀粉粒,其中可鉴定种属的淀粉粒主要来自于栎属、豆科和块茎类等非农作物,少量有可能来自于粟黍类作物。虽然分析样品较少,提取出的淀粉粒数量不多,但这一结果或许表明采集植物有可能构成了裴李岗遗址居民植物性食物的主体。结合贾湖、莪沟、石固和寨根等裴李岗文化遗址的植物考古学研究,裴李岗文化居民的食物结构具有广谱性特征。本研究为全面认识中原地区裴李岗文化居民食物构成和聚落生业经济,深入探讨中原地区早期农业形成过程等提供了新思路和新证据。     

Sweet potato (Ipomoea batatas) and banana (Musa sp.) microfossils in deposits from the Kona Field System,Island of Hawaii

Analysis of plant microfossils (pollen, phytoliths, starch grains and xylem cells) was carried out on 12 soil samples from a variety of pre-contact archaeological features in South Kona within a portion of what has been termed the Kona Field System, on the Island of Hawaii. The oldest radiocarbon ages of the sampled deposits are 1300–1625 AD and 1310–1470 AD. The pollen and phytolith evidence suggests a change from more to less trees and shrubs in the area as a result of human activity. We found phytoliths of banana (Musa sp.) leaves in most and starch grains and xylem cells of tuberous roots of c.f. sweet potato (Ipomoea batatas) in all of the samples, suggesting that the sampled features were associated with these crops and that both crops were cultivated intensively within the study area. Higher concentrations (volumetric) of starch and xylem in samples from older deposits suggest that cultivation was more intensive then. The apparent absence of starch and xylem remains of other tuberous crops archaeologically identified elsewhere in Polynesia suggests that tuberous cropping within the study area was mono-specific.     

Plant microfossils in human dental calculus from Nemrik 9, a Pre-Pottery Neolithic site in Northern Iraq

Samples of dental calculus were taken from 11 human individuals buried at Nemrik 9, a Pre-Pottery Neolithic site in Northern Iraq. All of them represented the time span of ca. 9100–8600 bp. In total, 95 microfossils were retrieved from these samples, including 70 phytoliths, 9 starch granules or clusters of starch, 3 pollens, and 1 xylem fragment. Most microfossils could be attributed to C₃ cool season cereals, most likely wheat and barley, which is consistent with previous knowledge about the composition of crops in early farming communities living in the Fertile Crescent. In addition, three phytoliths and one starch granule typical of C₄ warm season grasses were recovered including one subangular and faceted starch granule, which might derive from a native grass, but is not diagnostic of any genus. Prior to assigning diagnostic status to this starch, exhaustive reference work on native grass seeds is necessary. The presence of one Phragmites phytolith suggests non-alimentary processing of reeds using teeth or perhaps using the stem of this grass as a toothbrush or toothpick.     

Paleoethnobotany in the Neotropics from Microfossils: New Insights into Ancient Plant Use and Agricultural Origins in the Tropical Forest

Analysis of plant microfossils (phytoliths, pollen, and starch grains) from archaeological and paleoecological sediments in the humid Neotropical forest can provide information on some formerly intractable problems in American paleoethnobotany and archaeology. Each technique has strengths that redress the other's shortcomings, and all three microfossils can be recovered from early sites, securely identified, and dated. Agricultural origins, Pleistocene/ Holocene environmental changes, and the evolution of slash-and-burn agriculture are three important issues that yield substantial results to phytolith, pollen, and starch grain study. Microfossils of a number of domesticates, including maize, manioc, squash, bottle gourd, arrowroot, and leren, have been identified in contexts dating from 9000 to 7000 radiocarbon years B.P. The scope and methodology of traditional paleoethnobotany should be expanded to routinely include microfossil study.     

A short note on starch and xylem of Colocasia esculenta (taro) in archaeological deposits from Pitcairn Island,southeast Polynesia

We present results of starch analysis of archaeological deposits from Pitcairn Island. High concentrations of starch grains preserved in cell membranes, and xylem tracheary elements, consistent with introduced Colocasia esculenta (taro) were found. Because of limited age control, we are uncertain if the microfossils are prehistoric. Problems associated with identifying taxa with small starch grains in extractions from weathered deposits are highlighted.     

Starch granules,dental calculus and new perspectives on ancient diet

Recent work in various parts of the world has suggested the possibility of ancient starch granules surviving and adhering to archaeological artefacts. Often this information is used to infer aspects of diet. One additional source for recovery of archaeological starch granules is dental calculus. The presence of plant food debris in dental calculus is well known but has not been not widely investigated using archaeological material. The extraction of starch granules from dental calculus represents a direct link to the consumption of starchy food by humans or animals. Using dental calculus also sidesteps many other questions still inherent in using starch granules to reconstruct aspects of ancient diet, such as the effects of diagenesis on their morphology; as the starches are trapped inside a concreted matrix they are less likely to alter over time. We used amylase digestion by a starch-specific enzyme to confirm the material as starch.     

Diet,Geography and Drinking Water in Polynesia: Microfossil Research from Archaeological Human Dental Calculus,Rapa Nui (Easter Island)

Microfossil analysis of human dental calculus provides consumption‐specific and archaeologically relevant data for evaluating diet and subsistence in past populations. Calculus was extracted from 114 teeth representing 104 unique individuals from a late 16^th to early 18^th century skeletal series on Rapa Nui (Easter Island) to address questions of human–environment interactions and possible dietary preference. Scanning electron microscopy was used in lieu of optical microscopy for its superior depth of field and resolution of surface detail. The calculus microfossil recovery produced 16,377 total biogenic silica microfossils: 4733 phytoliths and 11,644 diatoms. The majority of phytoliths correspond with the Arecaceae or palm family (n = 4,456) and the minority corresponds to the Poaceae or grass family (n = 277). Because of the relatively large sample size, we were able to test hypotheses related to age cohort, sex, dental element and geographic region. Results indicate no significant difference in phytolith or diatom recovery based on age cohort or sex. The high frequency and proportion of Arecaceae phytoliths found in calculus extracted from the anterior dentition suggests consumption of soft or cooked foods containing palm phytoliths and the high frequency of diatoms recovered from the southern part of the island argue for different sources of drinking water. Copyright © 2012 John Wiley & Sons, Ltd.     

Dirty teeth and ancient trade: Evidence of cotton fibres in human dental calculus from Late Woodland,Ohio

Analysis of ancient human dental calculus for the presence of inclusions related to diet and dental health has been overlooked in anthropological literature. Small particles of archaeobotanical debris, which would otherwise not be preserved in the archaeological record, can become incorporated into unmineralised plaque on teeth during mastication and oral manipulation. When plaque mineralises into calculus, debris is preserved in situ. Samples of dental calculus (n = 18) were collected from the Danbury site (33OT16) in Ottawa County, Ohio and viewed under a scanning electron microscope for inclusions. Analysis yielded a variety of noticeable inclusions, including mineralised bacteria, calcium‐phosphate crystalline structures and numerous phytoliths. Here we report the first evidence of fibres consistent with cotton (Gossypium spp.) embedded in the dental calculus from the Late Woodland component (900–1100 AD ) of the Danbury site. Prehistoric cotton has not been previously documented in Ohio. The distinct morphology of the Danbury cotton and its presence in the Late Woodland component at Danbury suggests long‐distance interaction at a time in Ohio when movement of exotic goods appeared to have diminished. These microscopic remains provide insight into paleoethnobotanical history of ancient Ohioans and attest to how analysis of dental calculus could be used to supplement other paleodietary and archaeological analyses. Copyright © 2010 John Wiley & Sons, Ltd.     

Evaluating the usefulness of phytoliths and starch grains found on survey artifacts

Archaeologists use survey artifacts to study any number of interesting topics. The focus of this study is to test the usefulness of starch grains and phytoliths found on artifacts recovered during archaeological survey. Phytolith and starch grain analysis was used to determine the level of environmental contamination on three types of medieval ceramics collected during survey work from plowed fields in the parish of Wicken, Northamptonshire, England. The plant residues found on these artifacts were compared with their surrounding soil and with contemporaneous excavated artifacts recovered from under the floorboards of a medieval house in nearby Wyton, Cambridgeshire, England. Through the use of the “piggyback” approach pioneered by Chandler-Ezell and Pearsall, phytoliths and starch grains were systematically removed from the artifacts surface. Residues associated with contamination were removed from the outermost layer of the artifact surface while potentially uncontaminated residues were removed from the innermost layer of the artifact surface. Matching phytoliths and starch grains were found on the outermost surface of the survey artifacts and in the surrounding soils. No phytoliths and starch grains were found on the innermost surface of the survey artifacts suggesting that residues from the surrounding soils did not penetrate into the pores and crevices of the artifacts. The overall results suggest that, although they are preliminary, there is potential for plant residue analysis of survey artifacts.     

Changes in starch grain morphologies from cooking

One of the three main plant microfossils, starch grains are increasingly used as markers of diet, plant domestication, tool use and site organization, because their morphology and features provide a means to identify the plant that produced them. However, starch grains are susceptible to damage when they are exposed to heat in the presence of water, as in cooking. We documented the changes that occur in the starch grains of 10 domesticated plant species due to exposure to different cooking methods, in order to better understand how cooking alters the appearance of the grains, and if these cooking methods might be identifiable in the archaeological record. Our results show that some cooking methods produce unique, identifiable damage on some types of plant starches, but generally each plant species reacts uniquely to cooking. In order to record the changes for each plant species, we have created a database, available at (http://www.osresearch.net/∼hollyf/starchdb/index.cgi), to which registered users can add their own images of cooked starch grains.     

Experimental assessment of maize phytolith and starch taphonomy in carbonized cooking residues

Many taphonomic studies of plant microfossils, specifically phytoliths and starch, are concerned with post-depositional movement, contamination, and morphological changes due to environmental fluctuations or plant processing. Additionally, the identification of phytoliths and starches archaeologically are based on their presence or absence. This paper examines whether it is possible to identify maize (Zea mays ssp. mays) phytolith and starch abundance associated with different processing behaviors as replicated through experimentally produced cooking residues. If successful, identification of likely associated processing and taphonomy of these microfossils will allow for a more refined interpretation of plant use as it relates to timing and plant form and processing.     

A combined procedure for recovering phytoliths and starch residues from soils,sedimentary deposits and similar materials

Presented is a combined procedure for recovering phytoliths and starch residues from soils, sedimentary deposits and similar materials. It is designed to be reliable, simple and time efficient, and is outlined in detail and summary as a practical, step-by-step method. It has been carried out successfully on many types of soils and other deposits, including clays, silts and sands; waterlogged, porous, peaty, volcanic and coralline soils; and sediment cores and coprolites from a range of environmental settings in both tropical and temperate climates. Mounting phytoliths and starch residues on slides for microscopy is included.     

Influence of grinding on the preservation of starch grains from rice

China is a major centre for rice domestication, where starch grain analysis has been widely applied to archaeological grinding tools to gain information about plant use by ancient Chinese societies. However, few rice starch grains have been identified to date. To understand this apparent scarcity of starch grains from rice, dry- and wet-grinding experiments with stone tools were carried out on four types of cereals: rice (Oryza sativa L.), foxtail millet (Setaria italica), Job's tears (Coix lacryma-jobi L.) and barley (Hordeum vulgare L.). The results reveal that dry-grinding produces significant damage to starches to the point where they may be undetected in archaeological samples, while wet-grinding causes only slight morphological changes to the starch grains. Moreover, rice starch grains have the most substantial alterations from dry-grinding, possibly impeding their identification. These findings provide a possible means to explain the relative scarcity of rice starch grains recovered from archaeological grinding tools, which it is suggested was caused by the use of the dry-grinding technique. Therefore, it is suggested that rice starch grains have been likely underrepresented in the archaeological record, and previous interpretations of starch analyses need to be reconsidered.     

Investigating crop processing using phytolith analysis: the example of rice and millets

The application of crop processing models to macro-botanical assemblages has traditionally been used to interpret past husbandry practices and organisation of labour involved in crop-processing. Phytoliths offer an alternative method of analysis because they are durable in most environments, regardless of whether plant parts are charred, and the identification of plant types and plant parts allows them to be used in much the same way as macro-botanical remains. Indeed macro-remains and phytoliths are complementary datasets for examining the input of plant parts, such as crop-processing waste, into archaeological deposits. We outline crop-processing models in relation to macro-remains and then develop the framework for their application to archaeological phytolith assemblages. Rice and millet processing models are explored in relation to patterns expected in both macro-remains and phytoliths. The utility of these models is demonstrated with archaeological evidence from the site of Mahagara, an early farming site in North-Central India. The results indicate a way to employ phytoliths in archaeology which complements the fragmentary evidence available from plant macroremains.     

The decomposition of starch grains in soils: implications for archaeological residue analyses

Recent research involving starch grains recovered from archaeological contexts has highlighted the need for a review of the mechanisms and consequences of starch degradation specifically relevant to archaeology. This paper presents a review of the plant physiological and soil biochemical literature pertinent to the archaeological investigation of starch grains found as residues on artefacts and in archaeological sediments. Preservative and destructive factors affecting starch survival, including enzymes, clays, metals and soil properties, as well as differential degradation of starches of varying sizes and amylose content, were considered. The synthesis and character of chloroplast-formed ‘transitory’ starch grains, and the differentiation of these from ‘storage’ starches formed in tubers and seeds were also addressed. Findings of the review include the higher susceptibility of small starch grains to biotic degradation, and that protective mechanisms are provided to starch by both soil aggregates and artefact surfaces. These findings suggest that current reasoning which equates higher numbers of starch grains on an artefact than in associated sediments with the use of the artefact for processing starchy plants needs to be reconsidered. It is argued that an increased understanding of starch decomposition processes is necessary to accurately reconstruct both archaeological activities involving starchy plants and environmental change investigated through starch analysis.     

Protocol for Recording Enamel Hypoplasia in Modern and Archaeological Caprine Populations

This paper outlines the first methodology for recording dental enamel hypoplasia in the high‐crowned dentition of modern and archaeological caprine teeth. The method has been developed and trialed on five caprine populations from Orkney (UK); two modern populations (Shetland and North Ronaldsay breeds) and three Neolithic assemblages from the archaeological sites of Knap of Howar, Skara Brae and Holm of Papa Westray. Problems associated with differential tooth wear, as well as the presence of coronal cementum, are discussed, and recommendations are given on the identification and recording of hypoplastic dental defects in caprines. Copyright © 2012 John Wiley & Sons, Ltd.     

Reassessing the northern limit of maize consumption in North America: stable isotope,plant microfossil,and trace element content of carbonized food residue

In combination, the analysis of carbonized food residue for stable C and N isotopes, elemental composition, and plant microfossils (phytoliths and starch granules) offers a powerful tool for understanding patterns of prehistoric maize (Zea mays) consumption in small-scale societies. Using this approach, we conclude that maize was more widely consumed in North America than previously suspected. Between ∼AD 700 and 1600, despite little or no archaeological evidence of gardening, corn was a widespread component of diet on the eastern Canadian prairies. This pattern, furthermore, extended into the adjacent boreal forest at about the same time. However, carbon (δ¹³C) and nitrogen (δ¹⁵N) values on food residue samples vary widely, suggesting significant overall dietary differences from one region to the next. Analysis of a subset of residue samples for elemental composition (using ICP-OES [inductively coupled plasma–optical emission spectrometry]) may help identify broad trends in the provenience of foods consumed at these sites.     

Incremental banding in dental cementum: Methods of preparation for teeth from archaeological sites and for modern comparative specimens

Analysis of incremental banding in dental cementum is a well-established means of determining the age and season of death of wild mammals. The dental cementum of domesticated mammals likewise can indicate age and season of death. Methods of preparation applicable to archaeological teeth differ from those used for modern specimens, however, and this paper describes two methods that have given excellent imaging on teeth of Bos taurus; one for modern teeth and the other for teeth from archaeological sites.