Isotopic tracing of the impact of mobility on infectious disease: The origin of people with treponematosis buried in hull,England, in the late medieval period

Treponematosis has been one of the most studied and debated infectious diseases in paleopathology, particularly from the standpoint of its origin, evolution, and transmission. This study links evidence for treponematosis in skeletons from the 14th–16th century AD cemetery of the Augustinian friary of Hull Magistrates Court, England, with data from stable isotope analysis to test the hypothesis that the people with treponemal disease buried at this site were not locally born and raised. The objective is to explore the potential of using stable isotope data to track the place of origin and extent of mobility of individuals with an infectious disease. Dental enamel samples of 12 skeletons were selected for strontium (⁸⁷Sr/⁸⁶Sr ratio) and oxygen (δ¹⁸O) stable isotope analysis based on the presence (six ‐ diseased) or absence (six ‐ controls) of bone changes associated with treponemal disease. The oxygen isotope ratios of all but three individuals (1047, 1121, 823) overlapped at two standard deviations with the inferred local precipitation range, and only one individual (1216) had a strontium isotope ratio outside the regional range. Two of the four had probable/possible treponemal bone changes. Those with treponemal bone changes were not demonstrably more likely to be migrants than those without such lesions. However, because of extensive documentary evidence for trade with the Baltic Sea area, and for merchants from towns such as Stralsund, Danzig and Elbing being in Hull, it is very plausible that the four migrants came from the Baltic area or even southern Sweden. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.     

Paleomobility in the Tiwanaku Diaspora: Biogeochemical analyses at Rio Muerto,Moquegua, Peru

Paleomobility has been a key element in the study of the expansion of ancient states and empires, including the Tiwanaku polity of the South Central Andes (AD 500–1000). We present radiogenic strontium and oxygen isotope data from human burials from three cemeteries in the Tiwanaku‐affiliated Middle Horizon archaeological site complex of Rio Muerto in the Moquegua Valley of southern Peru. At Rio Muerto, archaeological human enamel and bone values range from ⁸⁷Sr/⁸⁶Sr = 0.70657–0.72018, with a mean of ⁸⁷Sr/⁸⁶Sr = 0.70804 ± 0.00207 (1σ, n = 55). For the subset of samples analyzed for oxygen isotope values (n = 48), the data ranges from δ¹⁸O_{carbonate(VSMOW)} = +18.1 to +27.0‰. When contextualized with other lines of archaeological evidence, we interpret these data as evidence for an archaeological population in which the majority of individuals had “local” origins, and were likely second‐generation, or more, immigrants from the Tiwanaku heartland in the altiplano. Based on detailed life history data, we argue a smaller number of individuals came at different ages from various regions within the Tiwanaku polity. We consider whether these individuals with isotopic values consistent with “nonlocal” geographic origins could represent first‐generation migrants, marriage exchange partners, or occupationally mobile herders, traders or other travelers. By combining isotopic life history studies with mortuary treatment data, we use a person‐centered migration history approach to state integration and expansion. Isotopic analyses of paleomobility at the Rio Muerto site complex contribute to the role of diversity in ancient states by demonstrating the range of geographic origins rather than simply colonists from the Lake Titicaca Basin. Am J Phys Anthropol 155:405–421, 2014. © 2014 Wiley Periodicals, Inc.     

青海喇家遗址人类遗骸的锶同位素比值分析

喇家遗址位于青海省民和县,主体为齐家文化的遗存,距今大约3900~4300年。喇家遗址古代人类迁移活动的研究,对于探索黄河上游古代文明,推动该地区齐家文化研究,有着积极的学术意义。本文首先采用电感耦合等离子体质谱技术对喇家遗址出土的22个个体的44份牙釉质和骨骼样品进行了元素分析,根据检测结果排除了受到污染的2份骨骼样品。其次,通过热电离质谱分析方法对喇家遗址出土22个个体的42份牙釉质和骨骼样品及8个猪牙釉质样品的锶同位素比值进行了测定。检测数据表明,猪牙釉质的锶同位素比值的标准偏差远小于其他动物,可以推断猪由当地饲养的可能性是最大的,因此其牙釉质锶同位素比值可以代表当地的锶同位素水平。经过计算得到8个猪牙釉质的锶同位素比值的平均值为0.710930,将该平均值加或减2倍标准偏差可以得到喇家遗址当地的锶同位素比值范围在0.711058~0.710802之间。以此为前提可以推测,本次检测的22个个体中,有17个个体牙釉质的锶同位素比值在遗址当地的锶同位素比值范围内,可能为本地出生。还有2个个体牙釉质在当地的锶同位素比值范围上下限附近,姑且存疑;仅有3个个体牙釉质的锶同位素比值在遗址当地的锶同位素比值范围以外,表明这些个体可能在其他地区出生,去世后埋葬在遗址中。此外,数据分析还显示,本地出生人群牙釉质的锶同位素比值平均值与骨骼的锶同位素比值平均值比较接近,暗示喇家遗址当地古人类生活方式可能比较统一。     

Investigating regional mobility in the southern hinterland of the Wari Empire: biogeochemistry at the site of Beringa, Peru

Empires have transformed political, social, and environmental landscapes in the past and present. Although much research on archaeological empires focuses on large-scale imperial processes, we use biogeochemistry and bioarchaeology to investigate how imperialism may have reshaped regional political organization and regional migration patterns in the Wari Empire of the Andean Middle Horizon (ca. AD 600-1000). Radiogenic strontium isotope analysis of human remains from the site of Beringa in the Majes Valley of southern Peru identified the geographic origins of individuals impacted by the Wari Empire. At Beringa, the combined archaeological human enamel and bone values range from (87)Sr/(86)Sr = 0.70802 - 0.70960, with a mean (87)Sr/(86)Sr = 0.70842 ± 0.00027 (1σ, n = 52). These data are consistent with radiogenic strontium isotope data from the local fauna in the Majes Valley and imply that most individuals were local inhabitants, rather than migrants from the Wari heartland or some other locale. There were two outliers at Beringa, and these "non-local" individuals may have derived from other parts of the South Central Andes. This is consistent with our understanding of expansive trade networks and population movement in the Andean Middle Horizon, likely influenced by the policies of the Wari Empire. Although not a Wari colony, the incorporation of small sites like Beringa into the vast social and political networks of the Middle Horizon resulted in small numbers of migrants at Beringa.     

Lombards on the Move – An Integrative Study of the Migration Period Cemetery at Szólád,Hungary

In 2005 to 2007 45 skeletons of adults and subadults were excavated at the Lombard period cemetery at Szólád (6^th century A.D.), Hungary. Embedded into the well-recorded historical context, the article presents the results obtained by an integrative investigation including anthropological, molecular genetic and isotopic (δ¹⁵N, δ¹³C, ⁸⁷Sr/⁸⁶Sr) analyses. Skeletal stress markers as well as traces of interpersonal violence were found to occur frequently. The mitochondrial DNA profiles revealed a heterogeneous spectrum of lineages that belong to the haplogroups H, U, J, HV, T2, I, and K, which are common in present-day Europe and in the Near East, while N1a and N1b are today quite rare. Evidence of possible direct maternal kinship was identified in only three pairs of individuals. According to enamel strontium isotope ratios, at least 31% of the individuals died at a location other than their birthplace and/or had moved during childhood. Based on the peculiar ⁸⁷Sr/⁸⁶Sr ratio distribution between females, males, and subadults in comparison to local vegetation and soil samples, we propose a three-phase model of group movement. An initial patrilocal group with narrower male but wider female Sr isotope distribution settled at Szólád, whilst the majority of subadults represented in the cemetery yielded a distinct Sr isotope signature. Owing to the virtual absence of Szólád-born adults in the cemetery, we may conclude that the settlement was abandoned after approx. one generation. Population heterogeneity is furthermore supported by the carbon and nitrogen isotope data. They indicate that a group of high-ranking men had access to larger shares of animal-derived food whilst a few individuals consumed remarkable amounts of millet. The inferred dynamics of the burial community are in agreement with hypotheses of a highly mobile lifestyle during the Migration Period and a short-term occupation of Pannonia by Lombard settlers as conveyed by written sources.     

Apotropaic Practices and the Undead: A Biogeochemical Assessment of Deviant Burials in Post-Medieval Poland

Apotropaic observances-traditional practices intended to prevent evil-were not uncommon in post-medieval Poland, and included specific treatment of the dead for those considered at risk for becoming vampires. Excavations at the Drawsko 1 cemetery (17^th–18^th c. AD) have revealed multiple examples (n = 6) of such deviant burials amidst hundreds of normative interments. While historic records describe the many potential reasons why some were more susceptible to vampirism than others, no study has attempted to discern differences in social identity between individuals within standard and deviant burials using biogeochemical analyses of human skeletal remains. The hypothesis that the individuals selected for apotropaic burial rites were non-local immigrants whose geographic origins differed from the local community was tested using radiogenic strontium isotope ratios from archaeological dental enamel. ⁸⁷Sr/⁸⁶Sr ratios ( = 0.7112±0.0006, 1σ) from the permanent molars of 60 individuals reflect a predominantly local population, with all individuals interred as potential vampires exhibiting local strontium isotope ratios. These data indicate that those targeted for apotropaic practices were not migrants to the region, but instead, represented local individuals whose social identity or manner of death marked them with suspicion in some other way. Cholera epidemics that swept across much of Eastern Europe during the 17^th century may provide one alternate explanation as to the reason behind these apotropaic mortuary customs, as the first person to die from an infectious disease outbreak was presumed more likely to return from the dead as a vampire.     

Stable Isotope and Trace Element Studies on Gladiators and Contemporary Romans from Ephesus (Turkey, 2nd and 3rd Ct. AD) - Implications for Differences in Diet

The gladiator cemetery discovered in Ephesus (Turkey) in 1993 dates to the 2^nd and 3^rd century AD. The aim of this study is to reconstruct diverse diet, social stratification, and migration of the inhabitants of Roman Ephesus and the distinct group of gladiators. Stable carbon, nitrogen, and sulphur isotope analysis were applied, and inorganic bone elements (strontium, calcium) were determined. In total, 53 individuals, including 22 gladiators, were analysed. All individuals consumed C₃ plants like wheat and barley as staple food. A few individuals show indication of consumption of C₄ plants. The δ¹³C values of one female from the gladiator cemetery and one gladiator differ from all other individuals. Their δ³⁴S values indicate that they probably migrated from another geographical region or consumed different foods. The δ¹⁵N values are relatively low in comparison to other sites from Roman times. A probable cause for the depletion of ¹⁵N in Ephesus could be the frequent consumption of legumes. The Sr/Ca-ratios of the gladiators were significantly higher than the values of the contemporary Roman inhabitants. Since the Sr/Ca-ratio reflects the main Ca-supplier in the diet, the elevated values of the gladiators might suggest a frequent use of a plant ash beverage, as mentioned in ancient texts.     

Utility of multiple chemical techniques in archaeological residential mobility studies: case studies from Tiwanaku- and Chiribaya-affiliated sites in the Andes

In the south central Andes, archaeologists have long debated the extent of Tiwanaku colonization during the Middle Horizon (AD 500-1000). We tested the hypotheses regarding the nature of Tiwanaku influence using strontium isotope, trace element concentration, and oxygen isotope data from archaeological human tooth enamel and bone from Tiwanaku- and Chiribaya-affiliated sites in the south central Andes. Strontium isotope analysis of 25 individuals buried at the Tiwanaku-affiliated Moquegua Valley site of Chen Chen demonstrates that it was likely a Tiwanaku colony. In contrast, no immigrants from the Lake Titicaca Basin were present in 27 individuals analyzed from the San Pedro de Atacama cemeteries of Coyo Oriental, Coyo-3, and Solcor-3; it is likely that these sites represent economic and religious alliances, but not colonies. However, strontium isotope analysis alone cannot distinguish movement between the Tiwanaku- and Chiribaya-affiliated sites in the Moquegua and Ilo Valleys of southern Peru. Analyzing oxygen isotope and trace element concentration data and comparing it with strontium isotope data from the same individuals provides a more detailed picture of residential mobility in the Tiwanaku and Chiribaya polities. In addition to monitoring diagenetic contamination, trace element concentration data identified movement during adulthood for certain individuals. However, these data could not distinguish movement between the Moquegua and Ilo Valleys. While oxygen isotope data could clearly distinguish the high-altitude sites from others, more data is needed to characterize the local oxygen isotope ratios of these regions. These data demonstrate the potential for archaeological reconstruction of residential mobility through multiple lines of evidence.     

Life history of the individuals buried in the St. Benedict Cemetery (Prague, 15th–18th Centuries): Insights from 14C dating and stable isotope (δ13C, δ15N, δ18O) analysis

Funerary practices and bioarchaeological (sex and age) data suggest that a mortality crisis linked to an epidemic episode occurred during the fifth phase of the St. Benedict cemetery in Prague (Czech Republic). To identify this mass mortality episode, we reconstructed individual life histories (dietary and mobility factors), assessed the population's biological homogeneity, and proposed a new chronology through stable isotope analysis (δ¹³C, δ¹⁸O and δ¹⁵N) and direct radiocarbon dating. Stable isotope analysis was conducted on the bone and tooth enamel (collagen and carbonate) of 19 individuals from three multiple graves (MG) and 12 individuals from individual graves (IG). The δ¹⁵N values of collagen and the difference between the δ¹³C values of collagen and bone carbonate could indicate that the IG individuals had a richer protein diet than the MG individuals or different food resources. The human bone and enamel carbonate and δ¹⁸O values suggest that the majority of individuals from MG and all individuals from IG spent most of their lives outside of the Bohemian region. Variations in δ¹⁸O values also indicate that all individuals experienced residential mobility during their lives. The stable isotope results, biological (age and sex) data and eight ¹⁴C dates clearly differentiate the MG and IG groups. The present work provides evidence for the reuse of the St. Benedict cemetery to bury soldiers despite the funeral protest ban (1635 AD). The Siege of Prague (1742 AD) by French‐Bavarian‐Saxon armies is identified as the cause of the St. Benedict mass mortality event. Am J Phys Anthropol 151:202–214, 2013. © 2013 Wiley Periodicals, Inc.     

Early African Diaspora in colonial Campeche, Mexico: strontium isotopic evidence

Construction activities around Campeche's central park led to the discovery of an early colonial church and an associated burial ground, in use from the mid-16th century AD to the late 17th century. Remains of some individuals revealed dental mutilations characteristic of West Africa. Analyses of strontium isotopes of dental enamel from these individuals yielded unusually high (87)Sr/(86)Sr ratios, inconsistent with an origin in Mesoamerica, but consistent with an origin in West Africa in terrain underlain by the West Africa Craton, perhaps near the port of Elmina, a principal source of slaves for the New World during the 16th century. These individuals likely represent some of the earliest representatives of the African Diaspora in the Americas.     

"These boots were made for walking": the isotopic analysis of a C(4) Roman inhumation from Gravesend, Kent, UK

As part of the road widening scheme between London and Dover, Oxford Archaeology South uncovered a large boundary ditch of Iron Age origin that contained Iron Age and Roman inhumations, adjacent to which was a small mid-late Roman cemetery, interpreted as a rural cemetery for Romano-British farmers. Grave goods in the cemetery were restricted to a few individuals with hobnailed boots. Bulk bone collagen isotopic analysis of 11 skeletons of Iron Age and Roman date gave a typical C(3) terrestrial signal (average δ(13) C = -19.8‰, δ(15) N = 9.3‰), but also revealed one (SK12671) with a diet which included a substantial C(4) component (δ(13) C = -15.2‰, δ(15) N = 11.2‰). This is only the second such diet reported in Roman Britain. Subsequent δ(18) O(c) and (87) Sr/(86) Sr measurements on the dental enamel in this individual were, however, consistent with a "local" origin, indicating that either C(4) protein was consumed in Late Roman Britain, or that he came from somewhere else, but where conditions gave rise to similar isotopic values. If we accept the latter, then it indicates that using oxygen and strontium isotopes alone to identify "incomers" may be problematic. The provision of hobnailed boots for the dead appears to have had a strong symbolic element in Late Roman Britain. We suggest that in this case the boots may be significant, in that he was being equipped for the long march home.     

Migration to the Medieval Middle East with the Crusades

During the 12th and 13th centuries thousands of people moved from Europe to the Middle East to fight, undertake pilgrimage, or settle and make a new life. The aim of this research is to investigate two populations from the Crusader kingdom of Jerusalem, by determining who was born in Europe and who came from the Middle East. Oxygen and strontium stable isotope analyses were conducted on the enamel of teeth from skeletal remains excavated from Crusader contexts. Twenty individuals from the coastal city of Caesarea (10 high status and 10 low status), and two local Near Eastern Christian farmers from the village of Parvum Gerinum (Tel Jezreel) were analyzed as a control sample. Results were compared with known geographic values for oxygen and strontium isotopes. The population of the city of Caesarea appears to have been dominated by European‐born individuals (probably 19/20, but at least 13/20), with few locals. This was surprising as a much higher proportion of locals were expected. Both controls from the farming village of Parvum Gerinum had spent their childhood in the area of the village, which matches our understanding of limited mobility among poor Medieval farmers. This is the first time that stable isotope analysis has been applied to the study of the migration of peoples between Medieval Europe and the Middle East at the time of the crusades. In view of these findings, we must now rethink past estimations of population social structure in Levantine coastal Medieval cities during the Crusader period. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

Mobility histories of 7th–9th century AD people buried at early medieval Bamburgh,Northumberland, England

Early Medieval England is described historically as a time when people migrated from the Continent to English shores. This study tests the hypothesis that those buried in the Bowl Hole cemetery, Bamburgh, Northumberland were nonlocally born, because of its royal status. Ninety‐one male and female adult, and nonadult, skeletons were studied. Isotope ratios of strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (δ¹⁸O) were generated for 78 individuals (28 females, 27 males, five “adults,” 18 nonadults). The mean Sr value for human enamel was 0.71044, standard deviation (sd) 0.001, and the mean O (δw) value is ?5.9‰, sd 1.6‰. Additionally, animal tooth enamel (mean Sr value 0.710587, sd 0.001; mean O value ?6.5‰, sd 1.5‰), local soil (mean Sr value 0.709184, sd 0.0006), snail shells (mean Sr value 0.708888, sd 0.0001), and soil samples from a 5 km transect heading inland (mean Sr value 0.709121, sd 0.0003), were analyzed for an indication of the isotopic composition of bioavailable Sr in the modern environment and to assess the impact of sea‐spray; water samples from a well, local rivers, and standing water were analyzed for local δ¹⁸O values (mean O value ?6.4‰, relative to VSMOW, sd 2.8‰). Over 50% of those buried at Bamburgh were nonlocal. All ages and both sexes produced “nonlocal” signatures; some suggested childhood origins in Scandinavia, the southern Mediterranean or North Africa. Stature and other indicators of health status indicated differences in quality of life between local and migrant groups. These differences did not extend to burial practices. Am J Phys Anthropol 151:462–476, 2013.© 2013 Wiley Periodicals, Inc.     

Strontium metabolism in teeth and enamel dose assessment: analysis of the Techa river data

People living on the banks of the Techa river were exposed to ⁹⁰Sr in the early 1950s. Data obtained by radiochemical measurements of extracted permanent teeth, ⁹⁰Sr autopsy measurements in bone and tooth samples, in vivo measurements of surface beta activity of the anterior teeth and whole-body counter (WBC) measurements of ⁹⁰Sr in the skeleton have been analyzed. Surface beta activity measurements indicate a biological half-life of ⁹⁰Sr of about 35 years in enamel. The WBC measurements have been performed since 1974 and a model for the age-dependent strontium retention in human bone has been used to extrapolate to previous time periods when the other measurement results were obtained. For the first decade after the intake, the ratio of the ⁹⁰Sr concentrations in teeth and bones were found to decrease with age at the time of major intake, from about 10 for 1-year-old children to about 0.3 for adults. There was a considerable variability of individual data within each age group. For adults, the correlation between ⁹⁰Sr in skeleton and teeth was not high at 0.47 according to radiochemical data for posterior teeth (molars and premolars) and 0.43 according to measurements of surface beta activity for anterior teeth. For children and adolescents there was no correlation between individual measurements in the skeleton and teeth. The absorbed dose in enamel due to ⁹⁰Sr in dentine has been calculated by Monte Carlo simulations of the electron transport. The results are in agreement with EPR measurements of the absorbed dose in the enamel of persons exposed, mainly due to ⁹⁰Sr ingestion. Received: 19 July 1999 / Accepted: 5 May 2000     

Earliest Evidence for Social Endogamy in the 9,000-Year-Old-Population of Basta,Jordan

The transition from mobile to sedentary life was one of the greatest social challenges of the human past. Yet little is known about the impact of this fundamental change on social interactions amongst early Neolithic communities, which are best recorded in the Near East. The importance of social processes associated with these economic and ecological changes has long been underestimated. However, ethnographic observations demonstrate that generalized reciprocity – such as open access to resources and land – had to be reduced to a circumscribed group before regular farming and herding could be successfully established. Our aim was thus to investigate the role of familial relationships as one possible factor within this process of segregation as recorded directly in the skeletal remains, rather than based on hypothetical correlations such as house types and social units. Here we present the revealing results of the systematically recorded epigenetic characteristics of teeth and skulls of the late Pre-Pottery Neolithic community of Basta in Southern Jordan (Figure S1). Additionally, mobility was reconstructed via a systematic strontium (Sr) isotope analysis of tooth enamel of the Basta individuals. The frequency of congenitally missing maxillary lateral incisors in the 9,000-year-old community of Basta is exceptionally high (35.7%). Genetic studies and a worldwide comparison of the general rate of this dental anomaly in modern and historic populations show that the enhanced frequency can only be explained by close familial relationships akin to endogamy. This is supported by strontium isotope analyses of teeth, indicating a local origin of almost all investigated individuals. Yet, the accompanying archaeological finds document far-reaching economic exchange with neighboring groups and a population density hitherto unparalleled. We thus conclude that endogamy in the early Neolithic village of Basta was not due to geographic isolation or a lack of exogamous mating partners but a socio-cultural choice.     

Trans‐Atlantic slavery: Isotopic evidence for forced migration to Barbados

The question of the ultimate origin of African slaves is one of the most perplexing in the history of trans‐Atlantic slavery. Here we present the results of a small, preliminary isotopic study that was conducted in order to determine the geographical origin of 25 enslaved Africans who were buried at the Newton plantation, Barbados, sometime between the late 17th and early 19th century. In order to gain a more nuanced understanding of the slaves' origin, we used a combination of carbon, nitrogen, oxygen, and strontium isotope analyses. Carbon and nitrogen isotope ratios were determined in bone and dentinal collagen; oxygen and strontium isotopes were measured in tooth enamel. Results suggest that the majority of individuals were born on the island, if not the estate itself. Seven individuals, however, yielded enamel oxygen and strontium ratios that are inconsistent with a Barbadian origin, which strongly suggests that we are dealing with first‐generation captives who were brought to the island with the slave trade. This idea is also supported by the fact that their carbon and nitrogen stable isotope values differ markedly between their teeth and bones. These intra‐skeletal shifts reflect major dietary changes that probably coincided with their enslavement and forced migration to Barbados. While it is impossible to determine their exact origins, the results clearly demonstrate that the slaves did not all grow up in the same part of Africa. Instead, the data seem to suggest that they originated from at least three different areas, possibly including the Gold Coast and the Senegambia. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.     

Strontium isotope analyses of large herbivore habitat use in the Cape Fynbos region of South Africa

The Cape Fynbos region of South Africa, a global biodiversity hotspot, hosted a diverse large mammal fauna till shortly after permanent European settlement (1652). How these animals survived in this exceptionally nutrient-poor environment is puzzling and it is generally believed that they restricted their movements to the more fertile shale areas. We tested the hypothesis that large herbivores avoid nutrient-poor limestone and sandstone fynbos shrublands in favour of shale-derived renosterveld vegetation using strontium (Sr) isotope analysis. If this technique could reconstruct the preferred feeding habitats of the contemporary fauna, it might also be useful for reconstructing the preferred feeding grounds of an extinct fauna. Using the assumption that small rodents have spatially restricted foraging activities, we determined the ⁸⁷Sr/⁸⁶Sr isotope ratios of rodent teeth to establish the isotopic signal characteristic of the different geological substrates in the area. We then analysed ⁸⁷Sr/⁸⁶Sr isotope ratios in the bones of a number of different large herbivores found in De Hoop Nature Reserve using laser ablation multi-collector inductively coupled plasma mass spectrometry. These values were compared to the bioavailable (rodent) values on the respective geological substrates. The technique identified differences in feeding substrate selection between different species and groups of the same species. The results also showed that shale renosterveld shrubland is not the exclusive source of nutrition for the large herbivores. Strikingly different isotope ratios among individuals in some populations pointed to significant dispersal events from distant sources. However, we were unable to pinpoint the exact feeding areas using Sr isotope analysis probably because some animals use a combination of substrates for feeding and because the geology of the study area is complex with graded isotope signals. We suggest that this technique is a valuable additional tool for exploring large mammal foraging behaviour on habitats associated with contrasting and less complex geology.     

Changing patterns of mobility as a response to climatic deterioration and aridification in the middle Holocene southern Sahara

The African Humid Period witnessed a rapid human re‐occupation of the Sahara as numerous lakes formed during the Holocene climatic optimum circa 10‐5 kya. Permanent waters attracted a variety of aquatic and terrestrial fauna allowing for long‐term occupation of specific paleolake basins. The Gobero paleolake in central Niger was one such location that preserves a unique mortuary record from the southern Sahara. Here, we use radiogenic strontium isotope analysis to investigate how human communities adapted to aridification throughout the Holocene. In particular, we examine the effects of increasing climate instability on patterns of human mobility. Results of radiogenic strontium isotope analysis of enamel and bone samples from Middle Holocene burials (～7.2–4.9 kya) indicate predominantly local values with no evidence for sex‐based variation. Comparisons of radiogenic strontium isotope data with previously published (Stojanowski and Knudson: Am J Phys Anthropol 146 (2011) 49–61) Early Holocene burials (～9.7–8.3 kya) indicate significant differences in both enamel and bone values. Middle Holocene individuals demonstrate a predominantly non‐local signature for enamel values and a predominantly local signature for bone values. Those individuals with non‐local bone values always demonstrated non‐local enamel values; however, the opposite was not the case. This suggests a divergence of mobility strategies during the Middle Holocene with a minority of individuals maintaining a more mobile existence throughout their life and others maintaining a similar strategy as Early Holocene hunter–gatherers that was tied to the paleolake basin. The more mobile individuals likely lived during the terminal phase of the lake's occupation. One response to aridification by Saharan peoples, then, was increasing mobility. Am J Phys Anthropol 154:79–93, 2014. © 2014 Wiley Periodicals, Inc.     

Pronghorn (Antilocapra americana) enamel phosphate δ18O values reflect climate seasonality: Implications for paleoclimate reconstruction

Stable oxygen isotope (δ¹⁸O) compositions from vertebrate tooth enamel are widely used as biogeochemical proxies for paleoclimate. However, the utility of enamel oxygen isotope values for environmental reconstruction varies among species. Herein, we evaluate the use of stable oxygen isotope compositions from pronghorn (Antilocapra americana Gray, 1866) enamel for reconstructing paleoclimate seasonality, an elusive but important parameter for understanding past ecosystems. We serially sampled the lower third molars of recent adult pronghorn from Wyoming for δ¹⁸O in phosphate (δ¹⁸O_PO4) and compared patterns to interpolated and measured yearly variation in environmental waters as well as from sagebrush leaves, lakes, and rivers (δ¹⁸O_w). As expected, the oxygen isotope compositions of phosphate from pronghorn enamel are enriched in ¹⁸O relative to environmental waters. For a more direct comparison, we converted δ¹⁸O_w values into expected δ¹⁸O_PO4* values (δ¹⁸O_W‐_PO4*). Pronghorn δ¹⁸O_PO4 values from tooth enamel record nearly the full amplitude of seasonal variation from Wyoming δ¹⁸O_W‐PO4* values. Furthermore, pronghorn enamel δ¹⁸O_PO4 values are more similar to modeled δ¹⁸O_W‐PO4* values from plant leaf waters than meteoric waters, suggesting that they obtain much of their water from evaporated plant waters. Collectively, our findings establish that seasonality in source water is reliably reflected in pronghorn enamel, providing the basis for exploring changes in the amplitude of seasonality of ancient climates. As a preliminary test, we sampled historical pronghorn specimens (1720 ± 100 AD), which show a mean decrease (a shift to lower values) of 1–2‰ in δ¹⁸O_PO4 compared to the modern specimens. They also exhibit an increase in the δ¹⁸O amplitude, representing an increase in seasonality. We suggest that the cooler mean annual and summer temperatures typical of the 18th century, as well as enhanced periods of drought, drove differences among the modern and historical pronghorn, further establishing pronghorn enamel as excellent sources of paleoclimate proxy data.