Enamel Carbonate Research Articles

Isotope values reveal “canopy effect” in deer territoriality and maize consumption for dogs from archaeological sites in Kentucky dating to the Middle Woodland through Late Fort Ancient time periods

This research analyzes stable carbon, nitrogen, and oxygen isotope values in tooth collagen and enamel to investigate foraging and territorial behavior in white-tailed deer (Odocoileus virginianus Zimmermann) and maize (Zea mays Linneaus) consumption in dogs (Canis familiaris Linneaus). The study analyzed 22 deer teeth from 13 archaeological sites in Kentucky covering a span of approximately 1,500 years of human occupation. The article presents evidence of foraging and territorial behavior in white-tailed deer, identified through the “canopy effect” observed in deer stable carbon isotope values in remains spanning from the Middle Woodland (200 BCE – CE 500) to Late Fort Ancient (CE 1400 – 1680) time periods in Kentucky. Additionally, teeth samples from nine dog and one wolf (Canis lupus Linneaus) were analyzed and indicate significant consumption of maize in seven of the dog samples. These specimens came from seven archaeological sites in Kentucky dating from the Early through Late Fort Ancient (CE 1400 – 1680) time periods. The study also contributes to the growing database of isotope studies in the Eastern Woodlands by presenting carbon and nitrogen isotope values on deer bone collagen from nine deer bone samples from three of the same archaeological sites dating to the Middle Woodland to Early Late Woodland.

Systematics and paleobiology of new bison occurrences from the Late Pleistocene of central Mexico

This study presents new findings of bison remains associated with alluvial plains in central Mexico dating back to the Late Pleistocene. These discoveries encompass eight sites in Hidalgo (Conejos, Ventoquipa, Barranca del Berrendo, Barranca Jagüey Viejo, Las Cajas, El Barrio, Monte Alegre, and San Gabriel Azteca) and two sites in Puebla (Barranca Policarpio and Barranca Xocoa). Biometrical analysis was conducted on the herein studied material, consisting of a horn core fragment, a skull fragment, two mandible fragments, five isolated teeth, and several postcranial remains. A comparative study with selected specimens indicates the presence of Bison antiquus and B. cf. latifrons. The record represents the first reported occurrences of these species for the states of Hidalgo and Puebla respectively. Furthermore, the analysis of carbon (δ13C) and oxygen (δ18O) isotopes in tooth enamel apatite from the material of Hidalgo and Puebla was used to characterize the bison's diet and habitat, providing evidence of the flexible dietary regime observed in Pleistocene bison populations and that were common inhabitants of mixed environments. Body mass estimation of some individuals (average weight ≈ 450 kg) is in the lower limit of B. antiquus populations from the Late Pleistocene of North America. New knowledge about the geographical presence of Bison antiquus and B. cf. latifrons in central Mexico is provided. Comparison with another bison record of these species from North America suggests a biochronological delay between them, representing a younger time interval for Bison antiquus (maximum age at 50 ka), allowing us to biostratigraphically constrain some Mexican localities containing bison remains.

Home on the range: A multi-isotope investigation of ungulate resource partitioning at Ashfall Fossil Beds, Nebraska, USA

During the Miocene (ca. 23.0–5.3 Ma), North America's Great Plains were a broad mosaic of savanna-woodlands inhabited by a diverse ungulate fauna. We investigated resource partitioning among ungulates at Ashfall Fossil Beds State Historical Park (henceforth “Ashfall”) in north-central Nebraska to establish how taxa shared the landscape. This mid-Miocene (11.86 ± 0.13 Ma) site preserves a watering-hole filled with volcanic ash that entombed hundreds of skeletons of medium- and large-bodied ungulates. We analyzed carbon (δ13C), oxygen (δ18O), and strontium (87Sr/86Sr) isotopes in enamel from seven species: the rhinoceros Teleoceras major (n = 13); three horses (Cormohipparion occidentale, Pliohippus pernix, and Pseudhipparion gratum; n = 3 each); two camels (Procamelus grandis and Protolabis heterodontus; n = 1 each); and one small ruminant artiodactyl (Longirostromeryx wellsi; n = 3). Carbon isotope data indicate that all seven ungulates foraged in open habitats dominated by C3 plants (enamel δ13CVPDB range from −9.6‰ to −6.9‰) with little to no evidence of C4 plant consumption. The overall range in δ18OVPDB values is ca. 6‰ (−7.6‰ to −1.3‰), while the range for 87Sr/86Sr is narrow (0.70864–0.70898). Horses have significantly higher δ18O and 87Sr/86Sr than T. major, which we suggest indicates horses foraged in relatively dry habitats, while T. major inhabited wet habitats with different strontium sources. Both camels isotopically resemble horses, and Longirostromeryx wellsi has intermediate 87Sr/86Sr and wide-ranging δ18O values. Plotting Teleoceras and co-occurring ungulates in a model that tests for semi-aquatic behavior using δ18O suggests that T. major from Ashfall was semi-aquatic; ecology and behavior may have varied among Teleoceras species living in different places at different times. This study exemplifies how 87Sr/86Sr data complement δ13C and δ18O analyses when reconstructing ancient environments; they can provide nuanced ecological information even in landscapes with homogeneous bedrock.

Disaster victim identification: Stable isotope analysis and the identification of unknown decedents.

Within the complex world of disaster victim identification, or DVI, forensic science practitioners use a variety of investigative techniques to work toward a common goal: identification of the decedents, bringing closure to the affected communities. Identification is a complex undertaking; the event (disaster) also can be extraordinarily complex, as it may be an acute event, or one that spans months or years. Compounding this time issue, remains may be heavily fragmented, dispersed, commingled, or otherwise disrupted by either the perpetrators or the disaster itself. To help solve these complexities, we explore the use of stable isotope analysis (SIA) in DVI events. SIA can be used with a variety of body tissues (hair, nail, bone, and teeth), and each represents different time depths in a decedent's life. Bone collagen and tooth enamel carbonate are useful to reconstruct an individual's diet and source water intakes, respectively, leading to likely population or geographic origin determinations. Additionally, the carbon and nitrogen isotopic signatures of bone collagen have calculated intraperson ranges. These facts allow investigators to determine likely origin of remains using isotopic data and can be used to link skeletal elements (to an individual), or perhaps more importantly, show that remains are not linked. Application of SIA can thus speed remains identification by eliminating individuals from short lists for identification, linking or decoupling remains, and reducing the need for some DNA testing. These strategies and hypothesis tests should commence early in the DVI process to achieve maximum effectiveness.

Ecology of large ungulates in the northeastern Iberian Peninsula during the Upper Palaeolithic through stable isotopes and tooth wear analysis

The northeastern Iberian Peninsula acted as a refuge zone during the Late Pleistocene where the persistence of terrestrial ecosystems could provide hunter-gatherers with large prey, mainly horse (Equus ferus) and red deer (Cervus elaphus). Isotopic (δ13C, δ18O, δ15N) and dental wear (mesowear and microwear) analyses have been applied on the remains of both species from the archaeological sites of Arbreda and Bora Gran at Serinyà (Girona), where evidence of human occupation from the Mousterian to the Magdalenian has been attested. The incremental enamel analysis on horse teeth revealed seasonal variation in carbonate δ18O but no detectable change in carbonate δ13C values, reflecting a rather stable diet and habitat over the year. Nevertheless, higher inter-individual than intra-individual contrast in carbonate δ13C indicate different environmental conditions from one individual to another for each stratigraphic unit. In red deer teeth, seasonal signals in enamel carbonate δ13C and δ18O demonstrated mirrored trends. Further, red deer show higher δ13C values than those of horses, both in enamel carbonate and bone collagen, as well as higher variability in mesowear and microwear scores, reflecting a mixed-feeding habit. Despite a strong grazing signal in mesowear and microwear, the lower δ13C values for horses suggest a higher dependence on relatively more humid habitats than red deer, which likely foraged in dryer environments with xeric plants during winter. These differences in ecological partitioning are particularly well illustrated in distinct collagen δ13C and δ15N values during the harsh climatic conditions of the Final Gravettian coeval to the GS-3 or Last Glacial Maximum. The capacity of red deer to adapt to fluctuating environmental conditions contrasts with the niche persistence of horse allowed by the availability of mosaic habitat.

Stable isotope analysis evidences dietary changes in toxodontids (Mammalia, Notoungulata) across the Neogene-Quaternary from Argentina

Toxodontidae was an extinct family of South American notoungulates, widely studied systematically, but not so much from an ecological perspective. This work aims to improve the knowledge about variations in diet and habitats of different representatives of this group in the context of biotic and abiotic events throughout the last 20 My. The tooth enamel carbon isotope composition (δ13C) of 7 genera recorded in 11 localities of Central, West and Northeastern Argentina, from the Early Miocene to the Late Pleistocene, was analyzed. The diet of the toxodontids studied in this work range from mainly C3 resources during the Miocene, mixed C3-C4 in the Pliocene, to a significant consumption of C4 plants during the Pleistocene. Differences in diet during the Late Pleistocene were also recorded, associated with geographic (i.e., Northeastern vs. Central) and temporal (i.e., glacial vs. interglacial periods) variations, evidencing the adaptive capacity of the group under ecological and environmental pressures.

Stable isotope evidence for resource partitioning in extinct marine carnivores

Living pinnipeds play essential roles in marine ecosystems and display divergent lineage-specific foraging and habitat preferences. The origin of these ecological strategies remains unclear. We analyzed original (n = 22) and published (n = 93) stable carbon (δ13C) and oxygen (δ18O) isotope compositions of tooth enamel from fossil pinnipeds and coeval marine and terrestrial mammals from the late Early Miocene to early Middle Miocene Temblor Formation, the early Middle Miocene Round Mountain Silt Formation at Sharktooth Hill Bonebed, the Middle Miocene of lower levels of the Monterey Formation, and the late Middle Miocene Santa Margarita Formation from the eastern North Pacific Ocean; and original (n = 43) δ13C and δ18O values from the Early Pliocene Yorktown Formation in the western North Atlantic. As expected for aquatic mammals, pinnipeds and control marine mammals had low δ18O variability relative to coeval terrestrial mammals, indicating minimal diagenetic alteration. Among late Early Miocene and Middle Miocene pinnipeds, Allodesmus had lower δ13C values than coeval taxa indicating offshore foraging, in agreement with predictions based on skeletal morphology. However, Allodesmus from the late Middle Miocene Santa Margarita Formation had overlapping δ13C values with co-occurring cetaceans and pinnipeds suggesting preferential nearshore habitat. The stem otariid Pithanotaria had higher enamel δ13C values than co-occurring pinnipeds, indicating nearshore foraging. The stem odobenid Neotherium had intermediate δ13C values supporting foraging between nearshore and offshore predators. Conversely, the stem odobenid cf. Imagotaria had lower enamel δ18O but comparable δ13C values to coexisting pinnipeds, suggesting the exploitation of estuarine resources. At least two ecologically distinct pinniped groups also occurred in the Yorktown Formation. In this unit, the odobenid Ontocetus and some monachinae phocids were predominantly nearshore foragers, with higher enamel δ13C and δ18O values than simultaneously occurring marine mammals. The second group was exclusively composed of phocids, which had comparatively low δ13C and δ18O values, compatible with northward foraging movements along the western North Atlantic coast. The paleoecological profiles of fossils bear strong similarities to the life modes of extant pinniped communities, implying that extant foraging modes appeared early in pinniped evolution and that resource partitioning contributed to their community structure over time.

Shrouded in history: Unveiling the ways of life of an early Muslim population in Santarém, Portugal (8th- 10th century AD).

In around 716 AD, the city of Santarém, Portugal, was conquered by the Berber and Arab armies that swept the Iberian Peninsula and went on to rule the region until the 12th century. Archaeological excavations in 2007/08 discovered an Islamic necropolis (Avenida 5 de Outubro #2-8) that appears to contain the remains of an early Muslim population in Santarém (8th- 10th century). In this study, skeletal material from 58 adult individuals was analysed for stable carbon (δ13Ccol; δ13Cap), nitrogen (δ15N) and sulphur (δ34S) isotope ratios in bones, and stable oxygen (δ18O), carbon (δ13Cen) and radiogenic strontium (87Sr/86Sr) isotopes in tooth enamel. The results of this study revealed a dietary pattern of predominantly C3-plant and domestic C3-fed herbivore consumption during adulthood (δ13Ccol and δ15N, respectively) but a higher proportion of C4-plant input during childhood (δ13Cen) for some individuals-interpreted as possible childhood consumption of millet porridge, a common practice in North Africa-in those with unorthodox burial types (Groups 1 and 2) that was not practiced in the individuals with canonical burials (Group 3). In this first mobility study of a medieval Muslim population in Portugal, δ18ODW values revealed greater heterogeneity in Groups 1 and 2, consistent with diverse origins, some in more humid regions than Santarém when compared to regional precipitation δ18O data, contrasting the more homogenous Group 3, consistent with the local precipitation δ18O range. Ancient DNA analysis conducted on three individuals revealed maternal (mtDNA) and paternal (Y-chromosome) lineages compatible with a North African origin for (at least) some of the individuals. Additionally, mobility of females in this population was higher than males, potentially resulting from a patrilocal social system, practiced in Berber and Arab communities. These results serve to offer a more detailed insight into the ancestry and cultural practices of early Muslim populations in Iberia.

Diversification in subsistence pattern of animal resources in the Hengduan Mountains: Multi‐isotopic evidence of Yingpanshan and Guijiabao site (5300–4000 cal. BP), China

AbstractThe Hengduan Mountains are located on the southeastern edge of the Qinghai‐Tibet Plateau, where farmers began to settle 6000 years ago. Animal husbandry plays a significant role in the sustenance economies of agricultural civilizations. It is unclear how Neolithic people acquired animal resources in the Hengduan Mountains. We explore animal geographical origins and feeding practices using the strontium, carbon, and oxygen isotope composition of tooth enamel at the Guijiabao and Yingpanshan sites during the Neolithic Age in the Hengduan Mountains. Multi‐isotopic evidence demonstrates that animals originate from several different regions with diverse foods. Guijiabao domestic dogs and pigs with a mixed C3/C4 diet share a similarly broad dietary spectrum with humans as enclosed animals, but the other pigs are wild boars with a C3 diet, likely free‐range animals or directly captured as meat resources. Yingpanshan dogs and pigs are both domestic animals with a mixed C3/C4 or C4‐based diet, but pigs with different 87Sr/86Sr ratios are likely raised by dispersed feeding modes. The inhabitants had diverse approaches for obtaining animal resources, including husbandry, hunting, and exchange. Diverse animal subsistence patterns are closely related to the complex geographical environment, reflecting the adaptation of farmers living in the high mountain valley regions.

Effects of particle size, storage conditions, and chemical pretreatments on carbon and oxygen isotopic measurements of modern tooth enamel

Isotopic analysis of human tooth enamel can provide life history information useful in forensic identification. These applications depend on the availability of reference data documenting isotopic values for individuals with known life history and on the comparability of data from reference and case work samples. Here we build on previous methodological research, which has largely focused on paleontological and archaeological samples, and conduct experiments using enamel from modern human teeth targeting three sample preparation variables (sample particle size, storage conditions, and chemical pretreatments). Our results suggest that differences in particle size affect the efficiency of sample reactions during pretreatment and analysis, with coarse particles giving reduced loss of enamel carbonate during acid pretreatments but producing slightly higher oxygen isotope values than fine particles during analysis. Data for samples stored in dry and ambient environments following pretreatment were indistinguishable, suggesting no exchange of oxygen between samples and ambient water vapor. Finally, chemical pretreatments with a range of commonly used reactants and conditions showed a pervasive, moderate oxygen isotope shift associated with acetic acid treatment, which may be caused by exchange of enamel hydroxyl groups with reagents or rinse waters. Collectively, the results emphasize the importance of methodological standardization to improve comparability and reduce potential for bias in the forensic application of tooth enamel isotope data.

Diet and habitat of the late Middle Pleistocene mammals from the Casal de’ Pazzi site (Rome, Italy) using stable carbon and oxygen isotope ratios

The late Middle Pleistocene archaeological site of Casal de’ Pazzi (MIS 7, ∼240–200 ka) in central Italy provided a complex of paleontological (both fauna and flora) and archaeological evidence, as well as a cranial fragment of Homo heidelbergensis.Here, we investigated the stable carbon and oxygen isotopic ratios of tooth enamel from six herbivore species (Palaeoloxodon antiquus, Hippopotamus amphibius, Bos primigenius, Stephanorhinus kirchbergensis, Equus ferus, and Dama Dama) to contribute to the understanding of the paleoenvironment of the site through the reconstruction of the diet and habitat of Pleistocene mammals. Our results indicate that the analyzed taxa fed on C3 plants and exploited both closed and open environments. This is consistent with the macro-botanical remains (leaf fossil impressions of Zelkova sp., Laurus nobilis, and Cercis siliquastrum) found at Casal de’ Pazzi and pollen evidence from the nearby lake of Valle di Castiglione. The area around the site was characterized by diversified Mediterranean evergreen forest tree species, accompanied by mesophilic elements of the mixed deciduous oak and beach forest, alternating with diversified wooded/forested vegetation and xeric vegetation. This was the environmental context in which the late Middle Pleistocene Homo lived. Comparisons with published isotopic data from other European archaeological localities between ∼600 and 125 ka evidenced considerable environmental differences through time and space, according to the general climate trends and local factors, such as latitude, temperature, and vegetation composition.

Isotopic insights into the Early Acheulean (1.95 Ma–1.66 Ma) high-elevation paleoenvironments at Melka Kunture (Upper Awash Valley, Ethiopia)

In this paper, we present stable carbon and oxygen isotope analyses of fauna tooth enamel from Garba IVD (1.95 Ma) and Gombore IB (1.66 Ma), two Early Acheulean sites of Melka Kunture (Upper Awash, Ethiopia), and discuss faunal taxonomy and fossil pollen. Our aim is to infer the diet and habitat of the fossil fauna, as well as the environment of both sites, in order to provide a broader paleoecological reconstruction. During the Pleistocene, the vegetation of the highlands of Ethiopia belonged to the Dry evergreen Afromontane Forest and grassland complex, which is distinct from the savanna of lower elevations in eastern Africa. Our carbon isotopic results indicate that all the analyzed faunal taxa were grazers consuming C4 plants, whereas oxygen isotopic results discriminate the taxa according to their semiaquatic or terrestrial habitats. These results are consistent with the taxonomic composition of the faunal assemblages and the palynological results, suggesting extended mountain grasslands in the landscape at Garba IVD. In contrast, the carbon isotopic results do not totally agree with the pollen paleoenvironmental reconstruction at Gombore IB, where the open vegetation was interrupted by forests and bushy vegetation. Stable isotope and pollen data provide different outcomes (feeding strategies vs. nearby plants) and have different temporal and spatial resolutions. This is relevant when reconstructing past environments by using independent proxies. Furthermore, isotopic comparisons with other Early Pleistocene paleontological and archaeological sites from eastern Africa indicate that all the analyzed taxa in common fed on C4 plants and that their dietary strategies were not affected by variations linked to the difference in elevations.

Neolithic herding practices in the Southern Caucasus: Animal management in the early 6th millennium BCE at Masis Blur in Armenia’s Ararat Valley

The Southern Caucasus is traditionally an important area of livestock production and a key region in the spread of herding from southwestern Asia to Eurasia’s western steppe. Neolithic settlements appeared across the Southern Caucasus in the early 6th millennium BCE. How these communities used the landscape and managed livestock in the context of mixed farming is not well understood. Stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of bone collagen and stable carbon and oxygen (δ18O) isotope analysis of tooth enamel from faunal remains from Masis Blur, one of the earliest Neolithic sites in the Southern Caucasus, clarify how communities maintained herds in this topographically varied region. δ13C and δ15N values indicate hunting wild fauna in diverse environments. δ13C and δ18O values from sequentially sampled livestock teeth demonstrate markedly different strategies for managing cattle and caprines. Negative covariation in δ18O and δ13C values in most caprines suggest seasonal mobility to C3-dominated high elevation pastures in the summers, and/or winter foddering with water-stressed C3 or wild C4 plants. These seasonal strategies were in place in the earliest known phase of occupation at Masis Blur, indicating that Southern Caucasus Neolithic communities likely exploited a range of environments linking the lowland plains and mountainous zones.

Herbivore enamel carbon and oxygen isotopes demonstrate both Homo sapiens and Neanderthals exploited similar habitats in the Zagros Mountains

ABSTRACTThe extinction of Neanderthal populations has been attributed to the onset of cold and dry climatic conditions during Marine Isotope Stage 3 or their competition with anatomically modern humans for large game resources. However, decoupling climate from competition has long proved difficult. Loess sequences and pollen cores provide regional‐scale environmental information but are less well‐suited to providing local‐scale habitat information contemporaneous with hominin habitation of occupation sites. The relationship between climate and resource availability is particularly unknown in the Zagros mountain range where archaeological evidence for both Neanderthals and Homo sapiens occupation is documented. Here, we analyse carbon (δ13C) and oxygen (δ18O) stable isotopes measured from herbivore tooth enamel carbonates recovered from the Neanderthal and modern human occupation sites of Bawa Yawan Rockshelter and Shanidar Cave to trace local‐scale floral biome dynamics and climate conditions that influence the distribution and availability of large prey targeted by both hominin species. Shared isotopic composition of herbivorous fauna, largely represented by wild goats, from both sites spanning Neanderthal and Homo sapiens occupation indicate both hominin species exploited similar habitats during climatically similar phases.

A preliminary assessment of ancient diet and mobility in Archaic period Asia minor: A view from Panormos, near Didyma

The Archaic Period in the Aegean marks the establishment of colonies and settlements in the larger Mediterranean and Black Sea. But little is known of the character of any demic expansion and the character of daily life for non-elites. We report first results of stable carbon and oxygen isotope ratios in tooth enamel from thirteen individuals buried in an Archaic Period necropolis located in western Turkey. We also measured multiple teeth in three individuals, which allow us to consider life events during childhood. Results indicate greater dietary diversity than has been observed in other palaeodiet studies in the region. From a wide range of oxygen values, including individual inter-tooth variation, we suggest that some of the individuals buried at Panormos may have spent some time during childhood outside the Aegean climatic zone, including the Black Sea and the interior of Asia Minor.

Evaluating the fidelity of enamel isotopic data and environmental variation in paleoecological studies: A case study in wild, known-aged, modern white-tailed deer (Odocoileus virginianus)

Stable carbon and oxygen isotope variability in herbivore enamel is frequently used to evaluate seasonal changes in the diets of fossil taxa as well as their broader ecosystems. Unfortunately, these reconstructions are often based on small samples (i.e., < 5 individuals) and the impacts of inter- and intraindividual variation on these data are largely unknown due to the lack of a modern comparative framework from wild herbivore populations. In this study, we used serially-sampled isotope values from the mandibular dentition (M1, M2, M3) of five wild, male white-tailed deer (Odocoileus virginianus) with known life histories from the Piedmont National Wildlife Refuge (PNWR; central Georgia, USA), to test the fidelity to which seasonal ecosystem-level variability is reflected in enamel carbon and oxygen isotope values. δ13C values across all individuals and sampled teeth fell within −21‰ and − 15.8‰, thereby indicating a diet dominated by C3 vegetation throughout the spring, summer, fall and winter months. We find significant (p < 0.05) inter-individual differences in the means of M1, M2 and M3δ13C and δ18O values, with the exception of M2δ18O values. M1δ13C values were consistently depleted, while δ18O values were consistently enriched (relative to M2 and M3) across all individuals sampled, likely indicative of pre-weaning, milk-dominated diet. Finally, there was little change in δ18O values across the M1, M2 and M3 despite dramatic fluctuations in temperature at the PNWR. We hypothesize that the primary driver of this pattern is the depletion of M2δ18O values due to the amount effect. These data support a complex relationship between enamel isotopic variation and the fluctuation of abiotic and biotic ecosystem variables that should be more fully considered in paleoecological analyses.

Feeding habits of the Gomphothere Cuvieronius hyodon in Costa Rica:A biochemical approach

ABSTRACT The feeding and habitat habits of 12 gomphotheres Cuvieronius hyodon from the Pleistocene of Costa Rica were inferred using carbon and oxygen isotopic ratios of tooth enamel. The results indicate that these animals fed mainly on C3 plants and lived in forested areas and those specimens that lived in high altitudes and latitudes consumed more C3 plants compared to those that lived in low areas or low latitudes. This indicates that, in Costa Rica, the gomphotheres were specialists in the consumption of this type of plants, similar to that shown in some specimens from North and South America.

The role of status, diets, and mobility in understanding the impacts of urbanization in early medieval Bergen, Norway (St. Mary's Church): Insights from stable isotope analyses

AbstractThis research examines the diets and mobility of higher status individuals buried in the St. Mary's (Mariakirken) churchyard (1140 and 1248 AD), located in Bergen, Norway. Stable isotope data are used to explore the role that diets (preferential access, choice of foods) may have played in mitigating the negative impacts of rapid urbanization. Dietary reconstruction involved analysis of carbon (δ13C) and nitrogen (δ15N) stable isotope ratios from paired bone and tooth samples from St. Mary's individuals (N = 25). Oxygen isotope ratios (δ18O) were derived from analyses of tooth enamel carbonate to comment on individuals' origins and mobility (N = 26). Individualδ13C andδ15N collagen values indicate that St. Mary's individuals consumed variable diets, with some relying on marine animal protein almost exclusively, while others primarily consumed C3plants or animals that consumed C3plants as the main source of their dietary protein.δ18O ratios showed that some individuals originated outside of Bergen. Thus, the stable isotope evidence (δ13C andδ15N) indicates that diets of St. Mary's individuals were more varied, and in some cases, relied primarily on imported trade goods such as grain/grain fed animals, and marine resources. This reinforces the view that St. Mary's represented an affluent segment of the growing Bergen population, and that its members were heavily involved in trade. Oxygen isotopes show that some individuals spent time living outside of Bergen during childhood. These data suggest that diets were more variable within the St. Mary's sample than at contemporary Norwegian sites, and that the process of urbanization did not impact the people of Bergen in a unified way.

Paleoenvironmental changes in the Brazilian Pampa based on carbon and oxygen stable isotope analysis of Pleistocene camelid tooth enamel

ABSTRACTHere we present paleoenvironmental and paleoclimatic reconstructions of the Brazilian Pampa based on stable isotopes (δ13C, δ18O) in tooth enamel of the Pleistocene camelidsLama guanicoeandHemiauchenia paradoxafrom the Chuy Creek fossil assemblage, including oneH. paradoxafrom a stratigraphic level within a loess unit deposited during the Last Glacial Maximum (26.5–19 ka b2k). The δ13C results show that both species fed mostly on C3 plants, although the mixed diets ofL. guanicoeincluded ~30% C4 or CAM plants.H.paradoxahad C3 diets with &lt;10% C4 or CAM plants. Both species exhibit higher δ18O and aridity indexes compared to other mammals from the assemblage, consistent with ingestion of18O‐enriched water from plants growing in arid/semi‐arid conditions. A comparison with δ13C of camelids from Argentina indicates the camelids from Chuy Creek fed on vegetation similar to that of Dry Pampa, Monte and Patagonic xerophytic steppes. Aridification and expansion of dry steppes in southern Brazil suggest a climate‐driven northeastwards shift of the Arid Diagonal of South America that may have contributed to local extinction of the Pleistocene megafauna. These Lateglacial environmental changes are reflected in the characteristics of the plant and mammalian assemblages of the modern Brazilian Pampa.

On the relationship between collagen- and carbonate-derived carbon isotopes with implications for the inference of carnivore dietary behavior

Studies of Rancho La Brea predators have yielded disparate dietary interpretations when analyzing bone collagen vs. enamel carbonate—requiring a better understanding of the relationship between stable carbon isotopes in these tissues. Stable carbon isotope spacing between collagen and carbonate (Δca-co) has also been used as a proxy for inferring the trophic level of mammals, with higher Δca-covalues indicative of high carbohydrate consumption. To clarify the stable isotope ecology of carnivorans, past and present, we analyzed bone collagen (carbon and nitrogen) and enamel carbonate (carbon) of extinct and extant North American felids and canids, including dire wolves, sabertooth cats, coyotes, and pumas, supplementing these with data from African wild dogs and African lions. Our results reveal that Δca-covalues are positively related to enamel carbonate values in secondary consumers and are less predictive of trophic level. Results indicate that the foraging habitat and diet of prey affects Δca-coin carnivores, like herbivores. Average Δca-covalues in Pleistocene canids (8.7+/−1‰) and felids (7.0+/−0.7‰) overlap with previously documented extant herbivore Δca-covalues suggesting that trophic level estimates may be relative to herbivore Δca-covalues in each ecosystem and not directly comparable between disparate ecosystems. Physiological differences between felids and canids, ontogenetic dietary differences, and diagenesis at Rancho La Brea do not appear to be primary drivers of Δca-cooffsets. Environmental influences affecting protein and fat consumption in prey and subsequently by predators, and nutrient routing to tissues may instead be driving Δca-cooffsets in extant and extinct mammals.