Stable isotope analyses of amino acids reveal the importance of aquatic resources to Mediterranean coastal hunter-gatherers.

Determining the degree to which humans relied on coastal resources in the past is key for understanding long-term social and economic development, as well as for assessing human health and anthropogenic impacts on the environment. Prehistoric hunter-gatherers are often assumed to have heavily exploited aquatic resources, especially those living in regions of high marine productivity. For the Mediterranean, this view has been challenged, partly by the application of stable isotope analysis of skeletal remains which has shown more varied coastal hunter-gatherer diets than in other regions, perhaps due to its lower productivity. By undertaking a more specific analysis of amino acids from bone collagen of 11 individuals from one of the oldest and best-known Mesolithic cemeteries in the Mediterranean, at El Collado, Valencia, we show that high levels of aquatic protein consumption were achieved. By measuring both carbon and nitrogen in amino acids, we conclude that some of the El Collado humans relied heavily on local lagoonal fish and possibly shellfish, rather than open marine species. By contrast to previous suggestions, this study demonstrates that the north-western coast of the Mediterranean basin could support maritime-oriented economies during the Early Holocene.

Palaeoecological differences underlie rare co-occurrence of Miocene European primates.

BACKGROUND: The two main primate groups recorded throughout the European Miocene, hominoids and pliopithecoids, seldom co-occur. Due to both their rarity and insufficiently understood palaeoecology, it is currently unclear whether the infrequent co-occurrence of these groups is due to sampling bias or reflects different ecological preferences. Here we rely on the densely sampled primate-bearing sequence of Abocador de Can Mata (ACM) in Spain to test whether turnovers in primate assemblages are correlated with palaeoenvironmental changes. We reconstruct dietary evolution through time (ca. 12.6-11.4 Ma), and hence climate and habitat, using tooth-wear patterns and carbon and oxygen isotope compositions of enamel of the ubiquitous musk-deer Micromeryx. RESULTS: Our results reveal that primate species composition is strongly correlated with distinct environmental phases. Large-bodied hominoids (dryopithecines) are recorded in humid, densely-forested environments on the lowermost portion of the ACM sequence. In contrast, pliopithecoids inhabited less humid, patchy ecosystems, being replaced by dryopithecines and the small-bodied Pliobates toward the top of the series in gallery forests embedded in mosaic environments. CONCLUSIONS: These results support the view that pliopithecoid primates preferred less humid habitats than hominoids, and reveal that differences in behavioural ecology were the main factor underpinning their rare co-occurrence during the European Miocene. Our findings further support that ACM hominoids, like Miocene apes as a whole, inhabited more seasonal environments than extant apes. Finally, this study highlights the importance of high-resolution, local investigations to complement larger-scale analyses and illustrates that continuous and densely sampled fossiliferous sequences are essential for deciphering the complex interplay between biotic and abiotic factors that shaped past diversity.

An early dog from southeast Alaska supports a coastal route for the first dog migration into the Americas.

The oldest confirmed remains of domestic dogs in North America are from mid-continent archaeological sites dated approximately 9900 calibrated years before present (cal BP). Although this date suggests that dogs may not have arrived alongside the first Native Americans, the timing and routes for the entrance of New World dogs remain uncertain. Here, we present a complete mitochondrial genome of a dog from southeast Alaska, dated to 10 150 ± 260 cal BP. We compared this high-coverage genome with data from modern dog breeds, historical Arctic dogs and American precontact dogs (PCDs) from before European arrival. Our analyses demonstrate that the ancient dog belongs to the PCD lineage, which diverged from Siberian dogs around 16 700 years ago. This timing roughly coincides with the minimum suggested date for the opening of the North Pacific coastal (NPC) route along the Cordilleran Ice Sheet and genetic evidence for the initial peopling of the Americas. This ancient southeast Alaskan dog occupies an early branching position within the PCD clade, indicating it represents a close relative of the earliest PCDs that were brought alongside people migrating from eastern Beringia southward along the NPC to the rest of the Americas. The stable isotope δ13C value of this early dog indicates a marine diet, different from the younger mid-continent PCDs' terrestrial diet. Although PCDs were largely replaced by modern European dog breeds, our results indicate that their population decline started approximately 2000 years BP, coinciding with the expansion of Inuit peoples, who are associated with traditional sled-dog culture. Our findings suggest that dogs formed part of the initial human habitation of the New World, and provide insights into their replacement by both Arctic and European lineages.

Four millennia of Iberian biomolecular prehistory illustrate the impact of prehistoric migrations at the far end of Eurasia.

Population genomic studies of ancient human remains have shown how modern-day European population structure has been shaped by a number of prehistoric migrations. The Neolithization of Europe has been associated with large-scale migrations from Anatolia, which was followed by migrations of herders from the Pontic steppe at the onset of the Bronze Age. Southwestern Europe was one of the last parts of the continent reached by these migrations, and modern-day populations from this region show intriguing similarities to the initial Neolithic migrants. Partly due to climatic conditions that are unfavorable for DNA preservation, regional studies on the Mediterranean remain challenging. Here, we present genome-wide sequence data from 13 individuals combined with stable isotope analysis from the north and south of Iberia covering a four-millennial temporal transect (7,500-3,500 BP). Early Iberian farmers and Early Central European farmers exhibit significant genetic differences, suggesting two independent fronts of the Neolithic expansion. The first Neolithic migrants that arrived in Iberia had low levels of genetic diversity, potentially reflecting a small number of individuals; this diversity gradually increased over time from mixing with local hunter-gatherers and potential population expansion. The impact of post-Neolithic migrations on Iberia was much smaller than for the rest of the continent, showing little external influence from the Neolithic to the Bronze Age. Paleodietary reconstruction shows that these populations have a remarkable degree of dietary homogeneity across space and time, suggesting a strong reliance on terrestrial food resources despite changing culture and genetic make-up.

Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs.

Large predators are overabundant in mid-Cretaceous continental dinosaur assemblages of North Africa. Such unbalanced ecosystem structure involves, among predatory dinosaurs, typical abelisaurid or carcharodontosaurid theropods co-occurring with long-snouted spinosaurids of debated ecology. Here, we report calcium (Ca) isotope values from tooth enamel (expressed as δ44/42Ca) to investigate resource partitioning in mid-Cretaceous assemblages from Niger (Gadoufaoua) and Morocco (Kem Kem Beds). In both assemblages, spinosaurids display a distinct isotopic signature, the most negative in our dataset. This distinct taxonomic clustering in Ca isotope values observed between spinosaurids and other predators provides unambiguous evidence for niche partitioning at the top of the trophic chains: spinosaurids foraged on aquatic environments while abelisaurid and carcharodontosaurid theropods relied almost exclusively on terrestrial resources.

Deciphering diet and monitoring movement: Multiple stable isotope analysis of the viking age settlement at Hofstaðir, Lake Mývatn, Iceland.

OBJECTIVES: A previous multi-isotope study of archaeological faunal samples from Skútustaðir, an early Viking age settlement on the southern shores of Lake Mývatn in north-east Iceland, demonstrated that there are clear differences in δ(34)S stable isotope values between animals deriving their dietary protein from terrestrial, freshwater, and marine reservoirs. The aim of this study was to use this information to more accurately determine the diet of humans excavated from a nearby late Viking age churchyard. MATERIALS AND METHODS: δ(13)C, δ(15)N, and δ(34)S analyses were undertaken on terrestrial animal (n = 39) and human (n = 46) bone collagen from Hofstaðir, a high-status Viking-period farmstead ∼10 km north-west of Skútustaðir. RESULTS: δ(34)S values for Hofstaðir herbivores were ∼6‰ higher relative to those from Skútustaðir (δ(34)S: 11.4 ± 2.3‰ versus 5.6 ± 2.8‰), while human δ(13)C, δ(15)N, and δ(34)S values were broad ranging (-20.2‰ to -17.3‰, 7.4‰ to 12.3‰, and 5.5‰ to 14.9‰, respectively). DISCUSSION: Results suggest that the baseline δ(34)S value for the Mývatn region is higher than previously predicted due to a possible sea-spray effect, but the massive deposition of Tanytarsus gracilentus (midges) (δ(34)S: -3.9‰) in the soil in the immediate vicinity of the lake is potentially lowering this value. Several terrestrial herbivores displayed higher bone collagen δ(34)S values than their contemporaries, suggesting trade and/or movement of animals to the region from coastal areas. Broad ranging δ(13)C, δ(15)N, and δ(34)S values for humans suggest the population were consuming varied diets, while outliers within the dataset could conceivably have been migrants to the area.

Reconstruction of breastfeeding and weaning practices using stable isotope and trace element analyses: A review.

Biogeochemical methods using stable isotopes and trace elements have been increasingly developed and applied to reconstruct modern and ancient breastfeeding and weaning practices of mammals, including humans, because they offer direct proxies for the dietary intake of subadults. Carbon, nitrogen, and oxygen isotopes have been used to evaluate breast milk lipid, protein, and water intake, respectively. Carbon and sulfur isotopes have been used to estimate the content of weaning foods. The elemental concentrations of Sr and Ba in subadult tissues differ because of the dietary change during the weaning process. For analyses, various tissues have been used, such as hair, nail, blood, and feces for modern mammals and bone and teeth for ancient ones. Of these, trace element analysis of tooth enamel offers a good opportunity for the reconstruction of breastfeeding and weaning practices of the more distant past at finer resolution, although further understanding of the metabolism of trace elements is necessary. There are various tissue- and element-specific advantages and disadvantages, and a combination of different proxies can illuminate practices from various viewpoints. Finally, applying the geochemical reconstruction of breastfeeding and weaning practices to human ecology, primatology, and paleoanthropology is important; basic studies of the underlying physiological mechanisms and technical improvements in the analyses will further highlight avenues for future research.

Dietary practices in ancient populations from northern Chile during the transition to agriculture (Tarapacá region, 1000 BC-AD 900).

OBJECTIVE: The goal of this research is to understand the relevance of diet diversity during the transition to agriculture, in ancient populations from northern Chile, especially considering the significance of marine resources and crops in a lesser degree. METHODS: A total of 14 human individuals were sampled from the Tarapacá 40 cemetery. Both bone and tooth samples were collected. Samples were studied from bone/dentine collagen for carbon and nitrogen isotopic analysis; and bone/enamel apatite for carbon isotope analysis. Inferential statistical analyses were performed in order to compare Tarapacá 40 stable carbon and nitrogen isotope values with other Formative and Late Intermediate Period groups. A nonparametrical hypothesis Kruskal-Wallis test was used. RESULTS: The results show that the individuals from Tarapacá 40 are intermediate to the values observed for terrestrial and marine fauna as well as C3 and C4 plants. CONCLUSIONS: A gradual transition to crop consumption, especially maize, is suggested. This complemented the earlier hunter-gatherer tradition of marine resources and wild fruit consumption. Contrarily to the predictions made by some archaeologists, the results obtained for northern Chile contrast with the classical perspective of a "Neolithic Revolution" in which transition to agriculture occurred more abruptly and linearly.

Oral histories: a simple method of assigning chronological age to isotopic values from human dentine collagen.

BACKGROUND: Stable isotope ratios of carbon (δ(13)C) and nitrogen (δ(15)N) in bone and dentine collagen have been used for over 30 years to estimate palaeodiet, subsistence strategy, breastfeeding duration and migration within burial populations. Recent developments in dentine microsampling allow improved temporal resolution for dietary patterns. AIM: A simple method is proposed which could be applied to human teeth to estimate chronological age represented by dentine microsamples in the direction of tooth growth, allowing comparison of dietary patterns between individuals and populations. The method is tested using profiles from permanent and deciduous teeth of two individuals. SUBJECTS AND METHODS: Using a diagrammatic representation of dentine development by approximate age for each human tooth (based on the Queen Mary University of London Atlas), this study estimated the age represented by each dentine section. Two case studies are shown: comparison of M1 and M2 from a 19th century individual from London, England, and identification of an unknown tooth from an Iron Age female adult from Scotland. RESULTS AND CONCLUSIONS: The isotopic profiles demonstrate that variations in consecutively-forming teeth can be aligned using this method to extend the dietary history of an individual or identify an unknown tooth by matching the profiles.

Hunter-gatherers have less famine than agriculturalists.

The idea that hunter-gatherer societies experience more frequent famine than societies with other modes of subsistence is pervasive in the literature on human evolution. This idea underpins, for example, the 'thrifty genotype hypothesis'. This hypothesis proposes that our hunter-gatherer ancestors were adapted to frequent famines, and that these once adaptive 'thrifty genotypes' are now responsible for the current obesity epidemic. The suggestion that hunter-gatherers are more prone to famine also underlies the widespread assumption that these societies live in marginal habitats. Despite the ubiquity of references to 'feast and famine' in the literature describing our hunter-gatherer ancestors, it has rarely been tested whether hunter-gatherers suffer from more famine than other societies. Here, we analyse famine frequency and severity in a large cross-cultural database, in order to explore relationships between subsistence and famine risk. This is the first study to report that, if we control for habitat quality, hunter-gatherers actually had significantly less--not more--famine than other subsistence modes. This finding challenges some of the assumptions underlying for models of the evolution of the human diet, as well as our understanding of the recent epidemic of obesity and type 2 diabetes mellitus.

Stable isotopic reconstructions of adult diets and infant feeding practices during urbanization of the city of Edo in 17th century Japan.

The urbanization of the city of Edo, the capital of premodern Japan, has been assumed to be not as a result of natural increase but that of in-migration although this assumption has never been verified. To obtain information on natural fertility in Edo, we analyzed stable carbon and nitrogen isotopes in 46 adult and 84 subadult human skeletons excavated from the Hitotsubashi site (1657-1683 AD: the early Edo period), Tokyo, Japan and reconstructed their breastfeeding period, one of the most important determinants of fertility. Adult females are significantly more depleted in (15) N by 0.7‰ than adult males, suggesting a dietary differentiation between sexes and/or the effect of pregnancy. The changes in the nitrogen isotope ratios of subadults suggest that supplementary foods were introduced around the age of 0.2 years and weaning ended around 3.1 years, which agrees with descriptions in various historical documents of the period. The duration of breastfeeding in the Hitotsubashi population was relatively longer than those in modern industrial and traditional societies and four previously reported populations in medieval and in the industrial England. As later weaning closely associates with longer inter-birth interval for mothers, our data suggest a lower natural fertility for the Hitotsubashi population. Assuming that the proportion of married people was also lower in the major cities of the earlier Edo period, our results support the assumption that Edo developed and increased its population by attracting immigrants during urbanization.

Carbon, nitrogen and sulphur isotope data of archaeological fish and mammal bone collagen from Lithuania.

Until relatively recently, stable sulphur isotope analysis of bone collagen was seldom undertaken in bioarchaeological research. With increasing frequency, its application has proven useful in reconstructing palaeodiets and palaeoecologies, as well as identifying potential migration and mobility patterns. Here, sulphur (δ34S) isotope analysis, together with carbon (δ13C) and nitrogen (δ15N), was performed on six fish and 34 mammal bone collagen samples from 14 prehistoric sites in Lithuania dating from the Late Mesolithic (ca. 7000-5000 cal BC) to the Late Bronze Age (ca. 1100-500 cal BC). We present the first δ34S data from Lithuania, including coupled δ13C and δ15N data, offering a crucial dataset for future research to explore spatial and temporal variability in the region and beyond.

Stable isotope data of Neolithic and Eneolithic populations in the Balkans, 6600 to 4000 BC.

Stable isotopic ratios of carbon and nitrogen performed on collagen and tooth enamel offer invaluable insight into the diet of ancient populations. In the northern Balkans, most of these isotopic data have been collected as auxiliary information of radiocarbon dates, to correct a potential marine reservoir effect. In order to facilitate the access of the academic community to these data, we present a set of isotopic carbon and nitrogen ratios of human collagen samples for 188 individuals from 12 previously published sites together with hitherto unreleased data for 24 individuals from 4 sites from the Neolithic and Eneolithic period in Bulgaria and Romania. This collection also includes previously published carbon isotopic ratio measurements on tooth enamel of 34 individuals.

Human tooth enamel carbon and oxygen stable isotope dataset from chalcolithic Inamgaon (India).

The tooth enamel from the human remains of ten archaeological individuals belonging to a chalcolithic site at Inamgaon, District Pune, Maharashtra, were analysed for stable carbon and oxygen isotope compositions. The human remains of the involved individuals come from three consecutive periods: Period I (1600-1400 BC; n = 2), Period II (1400-1000 BC; n = 4), and Period III (1000-700 BC; n = 4). Enamel carbonate of twenty teeth (n = 20), two from each individual, were analysed to understand the inter- and intra-individual variations in isotope ratios across the three habitational periods. The acquired dataset will help in understanding isotope baseline values for the region in the prehistoric context. The subsequent research works in the region can reuse our data in collation with other datasets for comparative investigations.

"Here we go again": the inspection of collagen extraction protocols for 14C dating and palaeodietary analysis.

Archaeological bone collagen is highly useful for radiocarbon (14C) dating and palaeodietary reconstruction. However, collagen preservation and carbon contamination are essential considerations when extracting collagen, becoming especially crucial close to the limit of the method (50,000 years before present = BP). Strong progress has been achieved in the past two decades by 14C and stable isotopic laboratories in removing contamination from archaeological bones, but different pretreatment protocols have been proven to produce varying results. Here we compare three collagen extraction protocols used for palaeodietary studies and 14C dating, considering collagen yield, elemental and stable isotopic data, FTIR analysis, and 14C dates. We focus on the impact of ultrafiltration on the yield and quality of the extracted material. The results again underline the importance of rigorous decontamination methods to gain accurate 14C dates and demonstrate that different protocols have significant effects on the quality and yield of extracted collagen.

Late Glacial and Early Holocene human demographic responses to climatic and environmental change in Atlantic Iberia.

Successive generations of hunter-gatherers of the Late Glacial and Early Holocene in Iberia had to contend with rapidly changing environments and climatic conditions. This constrained their economic resources and capacity for demographic growth. The Atlantic façade of Iberia was occupied throughout these times and witnessed very significant environmental transformations. Archaeology offers a perspective on how past human population ecologies changed in response to this scenario. Archaeological radiocarbon data are used here to reconstruct demographics of the region over the long term. We introduce various quantitative methods that allow us to develop palaeodemographic and spatio-temporal models of population growth and density, and compare our results to independent records of palaeoenvironmental and palaeodietary change, and growth rates derived from skeletal data. Our results demonstrate that late glacial population growth was stifled by the Younger Dryas stadial, but populations grew in size and density during the Early to Middle Holocene transition. This growth was fuelled in part by an increased dependence on marine and estuarine food sources, demonstrating how the environment was linked to demographic change via the resource base, and ultimately the carrying capacity of the environment. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.

Collagen stable isotope data from East and Northeast Asia, c. 7000 BC-1000 AD.

Stable isotope analysis is routinely used in archaeology to answer questions related to past diets. As the technique matures, data from archaeological sites have been generated at an exponential rate over the past several decades, thus provided an invaluable opportunity to examine past dietary practices and subsistence economies in much larger geographical and temporal settings. In Asia, a significant proportion of isotopic data is published in non-English journals or in grey literature, therefore remains largely inaccessible to general researchers. In order to provide easier access to these data, and to encourage future large-scale meta-data analyses in Asia, this collection presents the most comprehensive set of collagen stable isotope data of carbon, nitrogen, and sulfur from East and Northeast Asia (29-51˚N, 96-136˚ E) to date, including sites located within the modern territories of the People's Republic of China, Mongolia, the Russian Federation, and the Republic of Korea. Using academic search engines such as Google Scholar, the Chinese National Knowledge Infrastructure (CNKI), and ScienceON, a total of 3,304 previously published archaeological human and faunal stable isotope data from 136 archaeological sites in East and Northeast Asia, spanning over a period of 8,000 years (c. 7000 BC to AD 1000) are collected. The collated data are deposited on the open-access platform IsoArcH (https://isoarch.eu/) for any interested parties to use.

Equine diet during protohistoric times in the Northeast of the Iberian Peninsula: Stable isotope data (C, N) from bone collagen.

The analysis of stable isotopes in bone collagen allows us to infer the diet of the animals studied. This dataset consists of isotopic signatures (δ13C and δ15N) obtained by isotope ratio mass spectrometry from the skeletal remains of 42 equines (horse, ass and their hybrids) from the Can Roqueta site (Sabadell, Northeast Iberian Peninsula). Their chronology spans from Late Bronze Age to Late Roman Period, with particular emphasis on the Early Iron Age. These animals were found in storage silos and graves and were probably sacrificed as ritual offerings. The isotopic values are accompanied by data to assess the quality of the collagen analyzed. This fills a gap in equine isotopic values for this region and chronology, which may be of use to archaeologists interested in the study of livestock management or palaeodiet.

Carbon and nitrogen stable isotopic data of premodern human skeletons from mainland Japan and the Ryukyu islands.

This dataset consists of carbon and nitrogen stable isotope ratios of bulk collagen extracted from 229 human skeletons from premodern Japan. All samples were derived from different individuals excavated from mainland Japan and the Ryukyu Islands. Most of the skeletal individuals were identified, sexed, and aged by physical anthropologists. Collagen samples were extracted from bone or root portion of tooth dentin. Collagen samples were measured by an elemental analyzer coupled to stable isotope ratio mass spectrometry. Stable isotope ratios are the useful proxy of palaeodiet, and this dataset can be used for dietary reconstruction of premodern people living in the Japan archipelago.

Palaeodietary traits of large mammals from the middle Miocene of Gracanica (Bugojno Basin, Bosnia-Herzegovina).

Recent excavations at the Gracanica coal mine (Bugojno Basin, Bosnia-Herzegovina) have unearthed numerous skeletal parts of fossil vertebrates, including a noteworthy collection of mammalian remains. Previous palaeoecological investigations of the Dinarides Lake System were established using stratigraphical, palaeofloral, and malacological data. However, large mammal remains have so far not been used to reconstruct the terrestrial palaeoenvironment of this important fossil ecosystem. Here, the palaeodietary preferences of large mammals were investigated, using a multiproxy approach by employing dental microwear and dental mesowear analysis, in order to provide new perspectives on the terrestrial palaeoecology of the Dinarides Lake System. The dental microwear of all available adult mammalian teeth was analysed. Dental mesowear analysis was employed for ungulate and proboscidean taxa, using mesowear scores and mesowear angles, respectively. The analysis reveals the presence of browsing, "dirty browsing", and mixed-feeding herbivorous taxa, with seasonal fruit, or even grass intake. Additionally, the analysis of the carnivores suggests the presence of hyaena- and cheetah-like hypercarnivores, as well as generalists. The palaeodietary traits of the fossil mammals suggest a closed canopy-like environment, which is supported by the fossil plant assemblage. Palaeopalynological data confirm the omnipresence of fleshy fruit-bearing plants, herbaceous taxa, as well as grasses, which justifies the seasonal fruit browsing, the common "dirty browsing", and the occasional grazing behaviour visualized for some of the fossil mammals from Gracanica.