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The assessment of the preservation status of archaeological and palaeontological tooth enamel is of vital importance in the interpretation of isotopic and elemental analyses that underpin chronological, dietary, and mobility studies. Transmission and ATR Fourier Transform Infra-red Spectroscopy (FTIR) have provided an important means of studying the presence and crystallographic context of key structural groups in tooth enamel. However, differences in sample preparation and measurement methods prevent the setting of absolute references to assess tooth enamel preservation. Here, we present TOOTHFIR, a dataset of FTIR indices developed to study the crystal-chemical properties of enamel bioapatite, from Miocene, Pliocene, Pleistocene, Holocene, and modern samples. Using collected data, we conducted a preliminary statistical meta-analysis to assess inter-lab measurement variability (relying on modern samples) and the extent to which the mixed data remains useful in revealing diagenetic patterns. Our results confirmed significant variations with measurement methodology although it remained possible to observe broad relationships between the values for FTIR indices and environmental parameters. In this respect, we introduced the use of principal component analysis to summarize FTIR data. To improve data comparability and interpretation of preservation status, we suggest several measures. 1. Introduction 2. Methodology 3. Results 3.1. Comparison of ATR vs. Transmission mode measurements 3.2. Assessment of tooth enamel crystallinity as a function of sample age 3.3. Relationships among PCI, WAMPI, API, and BPI indices according to sample age 3.4. PCA analysis of FTIR data and assessment of relationships with environmental parameters 3.5. Relationships between sample fluorine uptake and FTIR indices 4. Discussion 5. Conclusions

Carbon isotopic analysis has been challenging our ideas about hominin diet for nearly 30 years. The first study in 1994 revealed that Paranthropus robustus from South Africa consumed principally C3 foods (e.g., tree fruits and leaves) but also about 25% C4/CAM resources (e.g., tropical grasses and sedges). This result was largely consistent with morphological and dental microwear evidence suggesting P. robustus had a diet which included hard objects like nuts and seeds. Decades later, however, P. boisei from eastern Africa was shown to have eaten nearly 80% C4/CAM plants like the contemporaneous grass-eating primate Theropithecus. Moreover, dental microwear revealed no evidence of hard object consumption in P. boisei, suggesting a diet of tough foods such as grass or sedge leaf and stem. So Paranthropus presents us with two central problems: 1) Why do dietary proxies suggest different diets for the two robust australopiths despite their morphological congruity; and 2) How could P. boisei have consumed tough foods with teeth that seem unsuited to the task. Here we review these questions and more with a particular focus on new isotopic data from the Omo and insights that can be gleaned from mammals outside the haplorrhine primates. We argue that extant Primates do not capture the ecomorphological diversity of P. boisei and other extinct primates and should not narrowly circumscribe the behaviors we ascribe to extinct taxa. We also discuss possible digestive strategies for P. boisei in light of its morphology, dietary proxy data, food mechanical properties, and comparative data on mammalian digestive kinetics. info:eu-repo/semantics/publishedVersion

The timing and character of the Pleistocene peopling of the Americas are measured by the discovery of unequivocal artifacts from well-dated contexts. We report the discovery of a well-dated artifact assemblage containing 14 stemmed projectile points from the Cooper’s Ferry site in western North America, dating to ~16,000 years ago. These stemmed points are several thousand years older than Clovis fluted points (~13,000 cal yr B.P.) and are ~2300 years older than stemmed points found previously at the site. These points date to the end of Marine Isotope Stage 2 when glaciers had closed off an interior land route into the Americas. This assemblage includes an array of stemmed projectile points that resemble pre-Jomon Late Upper Paleolithic tools from the northwestern Pacific Rim dating to ~20,000 to 19,000 years ago, leading us to hypothesize that some of the first technological traditions in the Americas may have originated in the region.

Analysis of enamel stable carbon isotopes (δ13Cenamel) of fossil herbivores is an important tool for making inferences about Plio-Pleistocene vegetation structure in Africa and the environmental context of hominin evolution. Many palaeoecological studies implicitly or explicitly assume that individual variation in C3–C4 plant consumption among fossil herbivores directly reflects the abundance of C3 (trees, shrubs) or C4 (low-altitude tropical grasses) vegetation. However, a strong link between δ13Cenamel of herbivores and ecosystem vegetation structure has not been rigorously established. Here we combine δ13Cenamel data from a large dataset (n = 1,643) with multidecadal Landsat estimates of C3 woody cover across 30 African ecosystems to show that there is little relationship between intrataxonomic variation in δ13Cenamel and vegetation structure. This is especially true when removing forested ecosystems (>80% woody cover)—which numerous lines of evidence suggest are rare in the Plio-Pleistocene fossil record of eastern Africa—from our analyses. Our findings stand in contrast with the common assumption that variation in herbivore δ13Cenamel values reflects changes in the relative abundance of C3–C4 vegetation. We conclude that analyses using herbivore δ13Cenamel data to shed light on the environmental context of hominin evolution should look to explicitly community-level approaches for making vegetation inferences. Combining a published dataset of stable carbon isotopes from herbivore tooth enamel with multidecadal Landsat estimates of C3 woody cover across 30 African ecosystems, the authors show that there is little relationship between intrataxonomic variation in δ13C enamel and vegetation structure, leading them to recommend a community-level approach for making vegetation inferences.

Diet provides critical information about the ecology and environment of herbivores. Hence, understanding the dietary strategies of fossil herbivores and the associated temporal changes is one aspect of inferring paleoenvironmental conditions. Here, we present carbon isotope data from more than 1,050 fossil teeth that record the dietary patterns of nine herbivore families in the late Pliocene and early Pleistocene (3.6 to 1.05 Ma) from the Shungura Formation, a hominin-bearing site in southwestern Ethiopia. An increasing trend toward C(4) herbivory has been observed with attendant reductions in the proportions of browsers and mixed feeders through time. A high proportion of mixed feeders has been observed prior to 2.9 Ma followed by a decrease in the proportion of mixed feeders and an increase in grazers between 2.7 and 1.9 Ma, and a further increase in the proportion of grazers after 1.9 Ma. The collective herbivore fauna shows two major change points in carbon isotope values at ∼2.7 and ∼2.0 Ma. While hominin fossils from the sequence older than 2.7 Ma are attributed to Australopithecus, the shift at ∼2.7 Ma indicating the expansion of C(4) grasses on the landscape was concurrent with the first appearance of Paranthropus. The link between the increased C(4) herbivory and more open landscapes suggests that Australopithecus lived in more wooded landscapes compared to later hominins such as Paranthropus and Homo, and has implications for key morphological and behavioral adaptations in our lineage.

Evidence of mobiliary art and body augmentation are associated with the cultural innovations introduced by Homo sapiens at the beginning of the Upper Paleolithic. Here, we report the discovery of the oldest known human-modified punctate ornament, a decorated ivory pendant from the Paleolithic layers at Stajnia Cave in Poland. We describe the features of this unique piece, as well as the stratigraphic context and the details of its chronometric dating. The Stajnia Cave plate is a personal 'jewellery' object that was created 41,500 calendar years ago (directly radiocarbon dated). It is the oldest known of its kind in Eurasia and it establishes a new starting date for a tradition directly connected to the spread of modern Homo sapiens in Europe.

Bone collagen is an important material for radiocarbon, paleodietary, and paleoproteomic analyses, but it degrades over time, making such analyses more difficult with older material. Collagen preservation between and within archaeological sites is also variable, so that much time, effort, and money can go into the preparation and initial analysis of samples that will not yield meaningful results. To avoid this, various methods are employed to prescreen bone for collagen preservation (e.g., %N, microporosity, and FTIR spectroscopic analyses), but these are often destructive and/or require exportation for analysis. Here, we explore near-infrared spectroscopy as a tool for gauging the collagen content of ground and whole bone from about 500 to 45,000 years ago. We show that a portable spectrometer’s ability to quantify collagen content and classify specimens by preservation status is comparable to that of other popular prescreening methods. Moreover, near-infrared spectroscopy is non-destructive and spectra can be acquired in a few seconds.

Analysis of enamel stable carbon isotopes (δ

New approaches to the study of early hominin diets have refreshed interest in how and when our diets diverged from those of other African apes. A trend toward significant consumption of C(4) foods in hominins after this divergence has emerged as a landmark event in human evolution, with direct evidence provided by stable carbon isotope studies. In this study, we report on detailed carbon isotopic evidence from the hominin fossil record of the Shungura and Usno Formations, Lower Omo Valley, Ethiopia, which elucidates the patterns of C(4) dietary utilization in the robust hominin Paranthropus. The results show that the most important shift toward C(4) foods occurred at ∼2.37 Ma, within the temporal range of the earliest known member of the genus, Paranthropus aethiopicus, and that this shift was not unique to Paranthropus but occurred in all hominins from this fossil sequence. This uptake of C(4) foods by hominins occurred during a period marked by an overall trend toward increased C(4) grazing by cooccurring mammalian taxa from the same sequence. However, the timing and geographic patterns of hominin diets in this region differ from those observed elsewhere in the same basin, where environmental controls on the underlying availability of various food sources were likely quite different. These results highlight the complexities of dietary responses by hominins to changes in the availability of food resources.

Examination of the feeding habits of mammalian species such as the African elephant (Loxodonta africana) that range over large seasonally dynamic areas is exceptionally challenging using field-based methods alone. Although much is known of their feeding preferences from field studies, conclusions, especially in relation to differing habits in wet and dry seasons, are often contradictory. Here, two remote approaches, stable carbon isotope analysis and remote sensing, were combined to investigate dietary changes in relation to tree and grass abundances to better understand elephant dietary choice in the Kruger National Park, South Africa. A composited pair of Landsat Enhanced Thematic Mapper satellite images characterising flushed and senescent vegetation states, typical of wet and dry seasons respectively, were used to generate land-cover maps focusing on the forest to grassland gradient. Stable carbon isotope analysis of elephant faecal samples identified the proportion of C3 (typically browse)/C4 (typically grass) in elephant diets in the 1–2 days prior to faecal deposition. The proportion of surrounding C4 land-cover was extracted using concentric buffers centred on faecal sample locations, and related to the faecal %C4 content. Results indicate that elephants consume C4 vegetation in proportion to its availability in the surrounding area during the dry season, but during the rainy season there was less of a relationship between C4 intake and availability, as elephants targeted grasses in these periods. This study illustrates the utility of coupling isotope and cost-free remote sensing data to conduct complementary landscape analysis at highly-detailed, biologically meaningful resolutions, offering an improved ability to monitor animal behavioural patterns at broad geographical scales. This is increasingly important due to potential impacts of climate change and woody encroachment on broad-scale landscape habitat composition, allowing the tracking of shifts in species utilisation of these changing landscapes in a way impractical using field based methods alone.

Stable carbon isotopes and occlusal microwear fabrics preserve direct, complementary evidence relating to the biogeochemistry and mechanical properties of foods that are consumed, and thus inform the diets of extinct individuals. We evaluate variation in microwear texture and carbon isotope composition in Australopithecus africanus and Paranthropus robustus in relation to paleoenvironmental reconstructions for the deposits from which these fossils derive. The distributions of microwear texture data for 44 Australopithecus specimens from Makapansgat and Sterkfontein, and 66 Paranthropus from Swartkrans, Kromdraai and Drimolen are compared with isotopic data for 25 A. africanus and 25 P. robustus from these same deposits. Makapansgat Member 3 is reconstructed as having witnessed more closed conditions than Sterkfontein Member 4. The A. africanus sample from Sterkfontein exhibits greater variation in δ13C and microwear complexity data, and both sets of values tend to be lower at Makapansgat, which might relate to a more appreciable reliance on C4-based foods and the (perhaps seasonal) consumption of harder food items by the australopiths that were deposited at Sterkfontein. Swartkrans Member 1 appears to have been somewhat more open than Swartkrans Member 2, and while this is not reflected in microwear textures, the hominin δ13C values from Member 2 tend toward the lower side of the Member 1 range. Swartkrans Member 1 “Lower Bank” fossils display a wider range of δ13C values but a narrower range of microwear complexity values than those from Member 1 “Hanging Remnant.” Neither microwear texture nor carbon isotope data serve to differentiate specimens from Makapansgat and Sterkfontein that have been proposed to represent A. prometheus.

Carbon isotope analyses of tooth enamel have been widely employed by paleoecologists to understand past habitats. Most such studies use large- to medium-bodied mammals and exclude small taxa. However, analysis of fossil small mammals holds promise for resolving questions about past environments because these animals are often present in the fossil record (especially in South African cave sites), are diverse in dietary and habitat preference, yet have limited lifespans and home range sizes. Thus, the carbon isotope compositions of small mammal communities and/or species might reflect the composition of vegetation in local environments at fine scales. In this study, we assessed the degree to which carbon isotope compositions of small mammal tooth enamel record spatial changes in habitat in a southern African savanna environment. Modern small mammal specimens were collected from the pellet accumulations of three barn owl ( Tyto alba africanus ) roosts located within microhabitats varying from open grassland to mixed woodland. We examined rodent carbon isotope compositions within taxa, between taxa, and between tooth types in an effort to characterize variation within this group. We also compared rodent community δ 13 C enamel composition between microhabitat types to evaluate how well small mammal isotope data reflect vegetation composition local to the roosts. Our analyses suggest that the relationship between small mammal community carbon isotopic means and vegetation composition is complex, but that with appropriate taxonomic control and consideration of relative abundance, small mammals have potential as a proxy for reconstructing past habitats. To complement this modern study, we performed isotopic analysis of the enamel of small mammals from three hominin-bearing sites in the Cradle of Humankind World Heritage Site, South Africa. Our results suggest a greater contribution of C4 resources to the diets of small mammals and likely more C4 grass in the past than occurs today.

International audience; The ritual human burials and scattered fragments of human bones excavated from Dolni Vestonice II and Pavlov I (Czech Republic) in the 20th century provide a large body of evidence on morphology and funerary practices in the Gravettian as well as the population history of European Homo sapiens during the Upper Palaeolithic. A series of radiocarbon dates on charcoal and animal bone places the occupation of the sites predominantly between 31,000-29,000 cal BP (Early-Evolved Pavlovian) but direct radiocarbon dating of the human remains has not been previously undertaken. In 2013, human bones from Dolni Vestonice II and Pavlov I were sampled for aDNA analysis, including three skeletons from a triple burial (DV13, DV14, DV15), two skeletons from single burials (Pav1, DV16) and two unarticulated human bones (DV42, DV43). Small amounts of bone material were left over from the aDNA sampling, providing the first opportunity to directly date seven of the human individuals. Non-destructive pre-screening with near-infrared (NIR) spectroscopy indicated that sufficient collagen was preserved in the bone material for radiocarbon dating. We sampled very small amounts (32-202 mg) of bone material for collagen extraction, ultrafiltration and accelerator mass spectrometer (AMS) dating. Each collagen extract was dated multiple times using both graphite targets (ca. 800 mu g C) and the gas ion source (< 100 mu g C) of the AixMICADAS to obtain accurate and precise radiocarbon ages. The direct dates confirm the Pavlovian origin of the human remains and indicate that several of the radiocarbon dates carried out in the 1980s on associated charcoals were likely affected by low-level contamination of modern carbon. The results add seven individuals to the small collection of reliably dated Upper Palaeolithic humans in Europe.

Giant pandas are specialized herbivores that digest little of the bamboo they consume. A new study argues that pandas, like carnivores, get most of their energy from protein, explaining their carnivore-like guts and poor digestion. This may have facilitated their ancestors' transition to herbivory.

One approach to understanding the context of changes in hominin paleodiets is to examine the paleodiets and paleohabitats of contemporaneous mammalian taxa. Recent carbon isotopic studies suggest that the middle Pliocene was marked by a major shift in hominin diets, characterized by a significant increase in C4 foods in Australopithecus-grade species, including Australopithecus afarensis. To contextualize previous isotopic studies of A. afarensis, we employed stable isotopes to examine paleodiets of the mammalian fauna contemporaneous with A. afarensis at Hadar, Ethiopia. We used these data to inform our understanding of paleoenvironmental change through the deposition of the Hadar Formation. While the majority of the taxa in the Hadar fauna were C4 grazers, most show little change in the intensity of C4 food consumption over the 0.5 million-year interval sampled. Two taxa (equids and bovins) do show increases in C4 consumption through the Hadar Formation and into the younger, overlying Busidima Formation. Changes in the distributions of C4-feeders, C3-feeders and mixed-C3/C4-feeders in the sampled intervals are consistent with evidence of dietary reconstructions based on ecomorphology, and with habitats reconstructed using community structure analyses. Meanwhile, A. afarensis is one of many mammalian taxa whose C4 consumption does not show directional change over the intervals sampled. In combination with a wide range of carbon and oxygen isotopic composition for A. afarensis as compared to the other large mammal taxa, these results suggest that the C3/C4 dietary flexibility of A. afarensis was relatively unusual among most of its mammalian cohort.

Carbon isotope analysis of fossil micromammalian insectivores holds promise for resolving questions about past environments because these animals have restricted home ranges and are generalist feeders. Thus, their diets likely integrate ecological information about local habitats. In this study, we assessed the degree to which carbon isotope compositions of three sympatric shrew species record spatial changes in habitat in a mosaic southern African savanna environment. Sampling sites were located within 2 km of one another, and microhabitat conditions ranged from very open ( Shrew carbon isotope compositions varied with habitat in a predictable manner within our study area. While taxonomy also influenced δ13C values, this was largely due to differences in habitat preferences of individual taxa and the resultant variation in their relative abundance within each environment. Isotopic differences between habitat types were preserved within taxa where taxa occurred in multiple habitats. To complement this modern study, we performed isotopic analysis of the enamel of insect-eating fossil micromammals from the hominin sites Gladysvale and Sterkfontein in the Cradle of Humankind, South Africa. This subset of fossil micromammals consumed primarily C4-derived carbon.

Stable isotope analysis has long been used to study the dietary ecology of living and fossil primates, and there has been increasing interest in using stable isotopes to study primate habitat use and anthropogenic impacts on non-human primates. Here, we examine the stable carbon and nitrogen isotope compositions of chimpanzees (Pan troglodytes) from seven communities in Uganda across a continuum of habitat structure (closed to more open) and access to anthropogenic resources (no reliance to heavy reliance). In general, the hair δ(13) C, but not δ(15) N, values of these communities vary depending on forest structure and degree of anthropogenic influence. When integrated with previously published hair δ(13) C and δ(15) N values for Pan, it is apparent that modern "savanna" and "forest" Pan form discrete clusters in carbon and nitrogen isotope space, although there are exceptions probably relating to microhabitat specialization. The combined dataset also reveals that Pan δ(13) C values (but not δ(15) N values) are inversely related to rainfall (r(2) = 0.62). We converted Pan hair δ(13) C values to enamel equivalents and made comparisons to the fossil hominoids Sivapithecus sp., Gigantopithecus blacki, Ardipithecus ramidus, and Australopithecus anamensis. The δ(13) C values of the fossil hominins Ar. ramidus and Au. anamensis do not cluster with the δ(13) C values of modern Pan in "forest" habitats, or with fossil hominoids that are believed to have inhabited forests. Am. J. Primatol. 78:1070-1085, 2016. © 2016 Wiley Periodicals, Inc.

The selection of foods in any environment depends on a variety of factors, including the nutrient availability and antifeedant loads in the component habitats. How these nutritional properties vary and covary in time and space is not well known, particularly among wild plant species. We collected plant samples from several habitats within the Cradle of Humankind World Heritage Site in South Africa, and measured their macronutrient and antifeedant properties in order to explore how season, habitat, plant type, and plant organ affected the quality of these potential plant foods. Our results have implications for early hominin use of similar habitats.

The African savannas that many early hominins occupied likely experienced stark seasonality and contained mosaic habitats (i.e., combinations of woodlands, wetlands, grasslands, etc.). Most would agree that the bulk of dietary calories obtained by taxa such as Australopithecus and Paranthropus came from the consumption of vegetation growing across these landscapes. It is also likely that many early hominins were selective feeders that consumed particular plants/plant parts (e.g., leaves, fruit, storage organs) depending on the habitat and season within which they were foraging. Thus, improving our understanding of how the nutritional properties of potential hominin plant foods growing in modern African savanna ecosystems respond to season and vary by habitat will improve our ability to model early hominin dietary behavior. Here, we present nutritional analyses (crude protein and acid detergent fiber) of plants growing in eastern and southern African savanna habitats across both wet and dry seasons. We find that many assumptions about savanna vegetation are warranted. For instance, plants growing in our woodland habitats have higher average protein/fiber ratios than those growing in our wetland and grassland transects. However, we find that the effects of season and habitat are complex, an example being the unexpectedly higher protein levels we observe in the grasses and sedges growing in our Amboseli wetlands during the dry season. Also, we find significant differences between the vegetation growing in our eastern and southern African field sites, particularly among plants using the C4 photosynthetic pathway. This may have implications for the differences we see between the stable carbon isotope compositions and dental microwear patterns of eastern and southern African Paranthropus species, despite their shared, highly derived craniodental anatomy.

Discussions about early hominin diets have generally excluded grass leaves as a staple food resource, despite their ubiquity in most early hominin habitats. In particular, stable carbon isotope studies have shown a prevalent C4 component in the diets of most taxa, and grass leaves are the single most abundant C4 resource in African savannas. Grass leaves are typically portrayed as having little nutritional value (e.g., low in protein and high in fiber) for hominins lacking specialized digestive systems. It has also been argued that they present mechanical challenges (i.e., high toughness) for hominins with bunodont dentition. Here, we compare the nutritional and mechanical properties of grass leaves with the plants growing alongside them in African savanna habitats. We also compare grass leaves to the leaves consumed by other hominoids and demonstrate that many, though by no means all, compare favorably with the nutritional and mechanical properties of known primate foods. Our data reveal that grass leaves exhibit tremendous variation and suggest that future reconstructions of hominin dietary ecology take a more nuanced approach when considering grass leaves as a potential hominin dietary resource.

Species’ partitioning of resources remains one of the most integral components for understanding community assembly. Analysis of stable carbon and nitrogen isotopes in animal tissues has the potential to help resolve patterns of partitioning because these proxies represent the individual’s diet and trophic niche, respectively. Using free-ranging rodents in a southern African savanna as a model community, we find that syntopic species within habitats occupy distinct isotope niches. Moreover, species with strongly overlapping isotope niches did not overlap in their spatial distribution patterns, suggesting an underlying effect of competitive exclusion. Niche conservatism appears to characterize the behaviour of most species in our sample - with little or no observed changes across habitats - with the exception of one species, Mastomys coucha. This species displayed a generalist distribution, being found in similar abundances across a variety of habitats. This spatial pattern was coupled with a generalist isotope niche that shifted across habitats, likely in response to changes in species composition over the same spatial gradient. The case for M. coucha supports contentions that past competition effects played a significant evolutionary role in shaping community structures of today, including the absence of strong interspecific niche overlaps within particular habitats. Our study highlights the value of stable isotope approaches to help resolve key questions in community ecology, and moreover introduces novel analytical approaches to quantifying isotope niche breadths and niche overlaps that are easily comparable with traditional metrices.

Biogeochemical studies of hominin dietary ecology began decades ago, and, despite refinements, the basic tools being used and questions being asked have changed little since then. Carbon isotope analyses have had the most impact, with numerous studies showing that up to c.4 Ma, early hominins consumed primarily C3 vegetation, as do extant apes, but thereafter consumption of C4 foods became conspicuous if variable. Paranthropus boisei completely abandoned the ancestral C3 diet by at least 2 Ma to become a C4 consumer, a rarity among primates. These shifts were accompanied by changes in the australopith masticatory package. Applications using trace elements, particularly strontium and barium, as trophic level indicators have been less successful, partly because the distributions of trace elements in foodwebs are poorly understood. Similarly, while the oxygen isotope composition of tooth enamel unquestionably reflects ecology, the influences are complex and too poorly understood to allow unambiguous interpretation.

Laser ablation multi-collector ICP-MS (LA-MC-ICP-MS) is increasingly applied to measure the strontium isotope composition ( 87 Sr/ 86 Sr) of fossil or modern tooth samples in order to address questions about mobility. Recently, concerns have been raised that an analytical bias due to instrumental isotopic mass fractionation might be introduced when this method is used to sample across naturally curved tooth enamel surfaces. We address this concern by reanalyzing data that were originally produced using 750 μm linear LA-MC-ICP-MS scans on the external, slightly curved surfaces of fossil hominin teeth ( Australopithecus and Paranthropus ) from South Africa. By re-integrating the first and last 1/3 of the data along the original 750 μm linear scans, we compared 87 Sr/ 86 Sr results produced by sections of each scan with varying degrees of laser focus. The results show no evidence of any analytical scatter between strontium isotope values for the different sections of the curved tooth surfaces and results for the different sections of each linear scan agree well within the precision of the method (external 2σ ± 0.0004). Furthermore, each analytical session was bracketed by analysis of a curved rodent ( Otomys sp.) tooth in-house standard with up to ± 100 μm vertical change along the 750 μm linear scan. Long-term, average LA-MC-ICP-MS 87 Sr/ 86 Sr results for one such Otomys tooth standard (0.72989 ± 0.00029, n = 71) agree well with the solution MC-ICP-MS analysis of the same tooth (0.72976 ± 0.00002). New LA-MC-ICP-MS 87 Sr/ 86 Sr ratios, using both a 213 nm and solid-state 193 nm laser ablation system, for sets of consecutive 750 μm linear scans along the curved, outer tooth enamel surface on another single Otomys tooth in-house standard agree within ± 0.0004 regardless of progressively more extreme vertical change during analysis (± 10 μm to ± 900 μm). These results are similar to LA-MC-ICP-MS Sr isotope analyses, using the same instrumentation and methodology, of an in-house, polished, flat clinopyroxene mineral standard (LA: 0.70482 ± 0.00029, n = 155; solution: 0.70495 ± 0.00003). We conclude that, provided the stable 86 Sr/ 88 Sr ratio is used in conjunction with the exponential law to constantly correct for instrumental isotopic mass fractionation during acquisition, curved tooth enamel surfaces represent no impediment to accurate LA-MC-ICP-MS strontium isotope analyses.

Objectives We conducted stable isotope and dietary analyses of women from higher and lower socioeconomic status (SES) groups in Cali, Colombia. The objectives were to test between-group differences in stable isotope, dietary, and anthropometric characteristics, and to evaluate relationships between diet and stable isotope values. Methods Hair samples from 38 women (mean age 33.4) from higher and lower SES groups were analyzed for δ13C, δ15N, and δ34S values. Dietary intake was assessed via 24-h recalls. Anthropometric variables measured were body mass index, five body circumferences, and six skinfold thicknesses. Results Mean δ13C and δ15N values of the higher SES group (−16.4 and 10.3‰) were significantly greater than those of the lower SES group (−17.2 and 9.6‰; P

Intra-tooth stable isotope analysis of dentine provides a more sensitive means to examine infant and childhood life history in the past than conventional cross-sectional analyses that rely on age-at-death. In addition, reconstructions of early diet and life history using an intra-tooth approach circumvent potential problems associated with mortality bias, which may operate strongly during infancy and childhood. We present new intra-tooth stable carbon and nitrogen isotope profiles in dentine collagen of early forming permanent teeth in a sample of adults from the Medieval Nubian site of Kulubnarti. We interpret the profiles in terms of weaning behavior and dietary history, and we compare profiles generated from first molars and canines to explore the degree to which these tooth types correspond. We then compare the profiles to the occurrence of linear enamel hypoplasia to assess the relationship between the timing of the weaning process and stress events. Finally, we compare the longitudinal profiles to cross-sectional stable isotope data obtained from rib collagen to investigate how life histories might differ between those that survived into adulthood and those that did not. Results suggest that canine and first molar profiles are in broad agreement, that hypoplastic stress events occurred during rather than before or after the weaning process in our sample, and that survivors appear to have weaned earlier than the average non-survivor. We suggest that this approach may be useful for addressing the effects of selective mortality on reconstructions of early life history and the relationship between early life history and morbidity.

The enhanced dietary flexibility of early hominins to include consumption of C 4 /crassulacean acid metabolism (CAM) foods (i.e., foods derived from grasses, sedges, and succulents common in tropical savannas and deserts) likely represents a significant ecological and behavioral distinction from both extant great apes and the last common ancestor that we shared with great apes. Here, we use stable carbon isotopic data from 20 samples of Australopithecus afarensis from Hadar and Dikika, Ethiopia (>3.4–2.9 Ma) to show that this species consumed a diet with significant C 4 /CAM foods, differing from its putative ancestor Au. anamensis . Furthermore, there is no temporal trend in the amount of C 4 /CAM food consumption over the age of the samples analyzed, and the amount of C 4 /CAM food intake was highly variable, even within a single narrow stratigraphic interval. As such, Au. afarensis was a key participant in the C 4 /CAM dietary expansion by early australopiths of the middle Pliocene. The middle Pliocene expansion of the eastern African australopith diet to include savanna-based foods represents a shift to use of plant food resources that were already abundant in hominin environments for at least 1 million y and sets the stage for dietary differentiation and niche specialization by subsequent hominin taxa.

Carbon isotope studies of early hominins from southern Africa showed that their diets differed markedly from the diets of extant apes. Only recently, however, has a major influx of isotopic data from eastern Africa allowed for broad taxonomic, temporal, and regional comparisons among hominins. Before 4 Ma, hominins had diets that were dominated by C 3 resources and were, in that sense, similar to extant chimpanzees. By about 3.5 Ma, multiple hominin taxa began incorporating 13 C-enriched [C 4 or crassulacean acid metabolism (CAM)] foods in their diets and had highly variable carbon isotope compositions which are atypical for African mammals. By about 2.5 Ma, Paranthropus in eastern Africa diverged toward C 4 /CAM specialization and occupied an isotopic niche unknown in catarrhine primates, except in the fossil relations of grass-eating geladas ( Theropithecus gelada ). At the same time, other taxa (e.g., Australopithecus africanus ) continued to have highly mixed and varied C 3 /C 4 diets. Overall, there is a trend toward greater consumption of 13 C-enriched foods in early hominins over time, although this trend varies by region. Hominin carbon isotope ratios also increase with postcanine tooth area and mandibular cross-sectional area, which could indicate that these foods played a role in the evolution of australopith masticatory robusticity. The 13 C-enriched resources that hominins ate remain unknown and must await additional integration of existing paleodietary proxy data and new research on the distribution, abundance, nutrition, and mechanical properties of C 4 (and CAM) plants.

Field studies of plant stable carbon and nitrogen isotope composition have revealed relationships with temperature and precipitation. These relationships conform to theoretical predictions of how extrinsic factors impact on ecophysiological processes such as photosynthesis and nitrogen cycling. However, examination of many datasets reveals high levels of variation, especially across environments with moderate precipitation (

This chapter examines the potential for using stable carbon and nitrogen isotope analysis as a tool for primate conservation. An animal’s stable isotope composition reflects the food it consumes and is permanently recorded in its tissue and excreta. One of the strengths of stable isotope analysis is its ability to examine broad dietary changes through time and space. This is extremely useful for ecologists interested in migratory behavior or dietary shifts due to environmental change or human influence. Among primates, researchers have documented geographic variation in diet linked to local vegetation and have explored dietary change through time by comparing the stable isotope compositions of existing populations to museum specimens (i.e., historic populations). Primatologists have also used stable isotope analysis to compare the diets of primate groups with varying degrees of access to human foods. Since stable isotopes record diet and dietary change, we discuss the promise of this technique for conservation with an emphasis on nonhuman primates. Like other methods available to conservationists, stable isotope analysis is most useful when interpreted in a broader historical and ecological context, and when coupled with behavioral observations, input from local stakeholders, and documentation of habitat loss, anthropogenic impacts, and disease ecology.

Stable isotope analysis has become an important tool in ecology over the last 25 years. A wealth of ecological information is stored in animal tissues in the relative abundances of the stable isotopes of several elements, particularly carbon and nitrogen, because these isotopes navigate through ecological processes in predictable ways. Stable carbon and nitrogen isotopes have been measured in most primate taxonomic groups and have yielded information about dietary content, dietary variability, and habitat use. Stable isotopes have recently proven useful for addressing more fine-grained questions about niche dynamics and anthropogenic effects on feeding ecology. Here, we discuss stable carbon and nitrogen isotope systematics and critically review the published stable carbon and nitrogen isotope data for modern primates with a focus on the problems and prospects for future stable isotope applications in primatology. Am. J. Primatol. 74:969-989, 2012. © 2012 Wiley Periodicals, Inc.

Specimens of Australopithecus sediba from the site of Malapa, South Africa (dating from approximately 2 million years (Myr) ago) present a mix of primitive and derived traits that align the taxon with other Australopithecus species and with early Homo. Although much of the available cranial and postcranial material of Au. sediba has been described, its feeding ecology has not been investigated. Here we present results from the first extraction of plant phytoliths from dental calculus of an early hominin. We also consider stable carbon isotope and dental microwear texture data for Au. sediba in light of new palaeoenvironmental evidence. The two individuals examined consumed an almost exclusive C(3) diet that probably included harder foods, and both dicotyledons (for example, tree leaves, fruits, wood and bark) and monocotyledons (for example, grasses and sedges). Like Ardipithecus ramidus (approximately 4.4 Myr ago) and modern savanna chimpanzees, Au. sediba consumed C(3) foods in preference to widely available C(4) resources. The inferred consumption of C(3) monocotyledons, and wood or bark, increases the known variety of early hominin foods. The overall dietary pattern of these two individuals contrasts with available data for other hominins in the region and elsewhere.

Stable isotope analysis of consumer tissues document patterns of resource use because data are linearly related to isotope compositions of their source(s) (i.e., food, water, etc.). Deviations in parameters estimated for these relationships can arise from variations in consumer tissue-diet spacing (Δ(TS)) and the level of isotopic heterogeneity in the source(s). We present a set of simple hypotheses that distinguish between the effects of Δ(TS) and source isotope heterogeneity. The latter may arise via mixed diets, during tissue turnover, or by isotopic routing of dietary components. We apply these concepts to stable carbon and nitrogen isotope relationships between gut contents and body tissues of large mammal herbivores from mixed C(3)/C(4) South African savannas and test predictions based on the compound- and/or time-specific data archived within each material. Predicted effects of source isotope heterogeneity are readily detected in carbon isotope relationships between materials representing different time periods or comprising bulk versus protein-only diet components. Differences in Δ(TS) of carbon isotopes across mammal herbivore species with very different feeding niches (and diet isotope compositions) are likely to be small or non-existent in these habitats. Variations in Δ(TS) estimated for nitrogen isotopes are much greater, leading to inconsistencies that cannot be explained by diet or trophic level effects alone. The effects of source heterogeneity on isotopic relationships generate numerical artefacts that have been misinterpreted as variations in Δ(TS). We caution against generalized application of hypotheses based on assumptions of source isotopic homogeneity, even for single diets commonly used in laboratory studies. More careful consideration of how heterogeneity affects consumer-diet relationships is needed for many field and laboratory systems.

Longitudinal studies have revealed how variation in resource use within consumer populations can impact their dynamics and functional significance in communities. Here, we investigate multi-decadal diet variations within individuals of a keystone megaherbivore species, the African elephant ( Loxodonta africana ), using serial stable isotope analysis of tusks from the Kruger National Park, South Africa. These records, representing the longest continuous diet histories documented for any extant species, reveal extensive seasonal and annual variations in isotopic—and hence dietary—niches of individuals, but little variation between them. Lack of niche distinction across individuals contrasts several recent studies, which found relatively high levels of individual niche specialization in various taxa. Our result is consistent with theory that individual mammal herbivores are nutritionally constrained to maintain broad diet niches. Individual diet specialization would also be a costly strategy for large-bodied taxa foraging over wide areas in spatio-temporally heterogeneous environments. High levels of within-individual diet variability occurred within and across seasons, and persisted despite an overall increase in inferred C 4 grass consumption through the twentieth century. We suggest that switching between C 3 browsing and C 4 grazing over extended time scales facilitates elephant survival through environmental change, and could even allow recovery of overused resources.

Diet changes are considered key events in human evolution. Most studies of early hominin diets focused on tooth size, shape, and craniomandibular morphology, as well as stone tools and butchered animal bones. However, in recent years, dental microwear and stable isotope analyses have hinted at unexpected diversity and complexity in early hominin diets. Some traditional ideas have held; others, such as an increasing reliance on hard-object feeding and a dichotomy between Australopithecus and Paranthropus , have been challenged. The first known evidence of C 4 plant (tropical grasses and sedges) and hard-object (e.g., seeds and nuts) consumption dates to millions of years after the appearance of the earliest probable hominins, and there are no consistent trends in diet change among these species through time.

The stable carbon isotope composition of animal tissues represents the weighted sum of the variety of food sources eaten. If sources differ in digestibility, tissues may overrepresent intake of more digestible items and faeces may overrepresent less digestible items. We tested this idea using whole blood and faeces of goats ( Capra hircus L., 1758) fed different food mixtures of C3lucerne ( Medicago sativa L.) and C4grass ( Themeda triandra Forssk.). Although blood and faecal δ13C values were broadly consistent with diet, results indicate mismatch between consumer and diet isotope compositions: both materials overrepresented the C3(lucerne) component of diets. Lucerne had lower fibre digestibility than T. triandra, which explains the results for faeces, whereas underrepresentation of dietary C4in blood is consistent with low protein content of the grass hay. A diet switch experiment revealed an important difference in13C-incorporation rates across diets, which were slower for grass than lucerne diets, and in fact equilibrium states were not reached for all diets. Although more research is needed to link digestive kinetics with isotope incorporation, these results provide evidence for nonlinear relationships between consumers and their diets, invoking concerns about the conceptual value of “discrimination factors” as the prime currency for contemporary isotope ecology.

Accumulating isotopic evidence from fossil hominin tooth enamel has provided unexpected insights into early hominin dietary ecology. Among the South African australopiths, these data demonstrate significant contributions to the diet of carbon originally fixed by C 4 photosynthesis, consisting of C 4 tropical/savannah grasses and certain sedges, and/or animals eating C 4 foods. Moreover, high-resolution analysis of tooth enamel reveals strong intra-tooth variability in many cases, suggesting seasonal-scale dietary shifts. This pattern is quite unlike that seen in any great apes, even ‘savannah’ chimpanzees. The overall proportions of C 4 input persisted for well over a million years, even while environments shifted from relatively closed ( ca 3 Ma) to open conditions after ca 1.8 Ma. Data from East Africa suggest a more extreme scenario, where results for Paranthropus boisei indicate a diet dominated (approx. 80%) by C 4 plants, in spite of indications from their powerful ‘nutcracker’ morphology for diets of hard objects. We argue that such evidence for engagement with C 4 food resources may mark a fundamental transition in the evolution of hominin lineages, and that the pattern had antecedents prior to the emergence of Australopithecus africanus . Since new isotopic evidence from Aramis suggests that it was not present in Ardipithecus ramidus at 4.4 Ma, we suggest that the origins lie in the period between 3 and 4 Myr ago.