Dental Mesowear Research Articles

A tale from the Neogene savanna: Paleoecology of the hipparion fauna in the northern Black Sea region during the late Miocene

This paper investigates the paleoecology of the Neogene savanna in the northern Black Sea region during the late Miocene, focusing on the “Hipparion fauna” that inhabited the area. The study explores the dietary habits of various ungulates and carnivorans through dental mesowear and microwear patterns, aiming to infer aspects of trophic interactions and ecological niches occupied by different species. The research covers three sites that span from the late Khersonian (late Tortonian; MN11) to the late Maeotian (Messinian; MN13) stages. We report catastrophic bone accumulation at the Grebeniki and Cioburciu 1 sites. Results indicate a significant dietary diversity that is challenging the traditional assumptions about the “Hipparion fauna”. Rhinoceroses, specifically Chilotherium schlosseri and Aceratherium incisivum, are identified as true grazers, contradicting previous beliefs about their preference for forested or swampy ecosystems. The hipparions, traditionally considered open landscape foragers, are revealed as browsers or mixed-feeders. The study also highlights the diverse dietary traits among small antelopes, giraffids, and suids, emphasizing their adaptability to various environmental conditions. Data obtained on the hyaenid Adcrocuta eximia indicate a diet very similar to that of the bone-cracking spotted hyena. The microwear pattern of the cubs was very different from both adults and any other carnivorans used for comparison. The large felid Machairodus copei was characterized by a hypercarnivorous diet similar to lions, while smaller-size Ictitherium viverrinum was characterized by a more opportunistic feeding strategy. These findings suggest similarities and differences in feeding patterns between modern and Neogene savanna mammals. The presence of both grazing and browsing herbivores indicates a more heterogeneous landscape, with a mixture of open grasslands and denser vegetation. Additionally, the paper provides insights into the changing paleoenvironment, suggesting a transition from wooded grasslands to open landscapes during the late Miocene. Overall, this research contributes to a comprehensive understanding of the Neogene savanna ecosystem and challenges existing perceptions of the paleoecology of the “Hipparion fauna” in the northern Black Sea region.

Life in a Central European warm-temperate to subtropical open forest: Paleoecology of the rhinocerotids from Ulm-Westtangente (Aquitanian, Early Miocene, Germany)

The Ulm-Westtangente locality has yielded the most abundant vertebrate fauna from the Aquitanian stage in Germany. Its dating to the Mammal Neogene Zone 2a, a turnover in Cenozoic climate, makes it a crucial source for the understanding of faunal, paleoecological and paleoenvironmental specifics of the European Aquitanian. However, while most taxa from Ulm-Westtangente have been studied, little to no research has been conducted on the large herbivores, particularly on the two rhinocerotids Mesaceratherium paulhiacense and Protaceratherium minutum. Here, we used a multi-proxy approach to investigate the paleoecology of these two species. The remains of the smaller species P. minutum (438 to 685 kg) are twice as abundant as those of the larger M. paulhiacense (1389 to 2327 kg), but both display a similar age structure (~ 10% of juveniles, 20% of subadults and 70% of adults), mortality curves, and mild prevalence of hypoplasia (~ 17%). Results from dental mesowear, microwear, and carbon isotopes indicate different feeding preferences: both were C3 feeders but M. paulhiacense had a more abrasive diet and was probably a mixed feeder. Our study on rhinocerotids also yielded new paleoenvironmental insights, such as the mean annual temperature (15.8 °C) and precipitation (317 mm/year) suggesting rather warm and dry conditions.

Assessing diet and animal mobility in Iron Age Languedoc, southern France: New insights from a multiproxy approach

The societies living in the present-day Languedoc region during the Iron Age (7th-2nd c. BC) experienced a series of progressive transformations, including a demographic growth and an increase in social differentiation, affecting their economic, social and political structure. This context certainly influenced economic organisation, including farming strategies. However, the relationship between animal husbandry and the economical and political context is not completely understood in Iron Age Languedoc. Two key issues – the feeding strategies and the animal mobility in the hinterlands of Languedoc – are poor known. With the aim of providing new insights into our understanding of animal diet and mobility, we combined zooarchaeology (species representation and mortality profiles), dental microwear, dental mesowear and isotopes –strontium (87Sr/86Sr), oxygen (δ18O) and carbon (δ13C)– on domestic ungulates from five major Iron Age sites: Cayla de Mailhac, La Ramasse, Le Cailar, La Monédière and Lattara. The combination of these approaches enabled us to support the hypothesis of a local breeding of livestock, the animal pasture in nearby areas to the site, and the different animal management between caprines and cattle.

The role of climate change in the extinction of the last wild equids of Europe: Palaeoecology of Equus ferus and Equus hydruntinus during the Last Glacial Period

The last European wild equids —Equus ferus and Equus hydruntinus— were among the large mammals (or megafauna) that became extinct during the Late Quaternary Extinction Event disappearing from Europe during the Holocene. The role that the combined action of the major climatic changes of the Pleistocene/Holocene Transition and the human activities played in their extinction is not fully understood. The reduction of steppe-like biomes in Europe following the increase of mean global temperatures during the Holocene is usually regarded as the main event that triggered their disappearance, as both equids display typical morphological adaptations for open grasslands and grass eating. However, E. ferus and E. hydruntinus are found, often even co-occurring, in both warm and cold phases of the Late Pleistocene. Thus, the investigation of their niche occupation can help decipher whether their ecology and specialised dietary adaptations were the main reason of their decline following the early Holocene global warming. Here we investigate the feeding strategies of the two equids by studying their long- and short-term dietary adaptations through examination of their patterns of dental wear. As expected, dental mesowear points to a highly abrasive diet concordant with a grazing feeding behaviour for both E. ferus and E. hydruntinus which is consistent with their specialised morphological adaptations for open habitats. In contrast, dental microwear suggests a somewhat degree of plasticity in diets, as both species display microscopic features commonly recorded in modern mixed feeders. Such a flexibility may be the reason for which they could have persisted even when open grasslands were not the dominant landscape. Our findings provide a new line of evidence supporting the idea that human activities (e.g., competition with the first domestic forms brought from Eurasia and Africa) may have played a larger role in the extinction of some megafauna groups than climate change per se.

Dental mesowear analysis of the Columbian mammoth (Mammuthus columbi) from Tultepec, Estado de México, México

The ontogenetic age and dietary preference of 11 individuals of Mammuthus columbi, from the Late Pleistocene sites of Tutlepec I and Tultepec II, Estado de México, were estimated. To accomplish this, their jaws and molars were measured and examined and the dental mesowear of the molars was analyzed. The estimated age (in African Elephant Age) of most individuals studied was less than 30 years, and only a single individual was approximately 45 years old. The average mesowear angle in the molars indicates great variability in their food preferences, finding individuals that are strictly leaf browsers, strictly grazers, on a mixed diet (C3/C4), mostly browsers, and mostly grazers. Additionally, differences in mesowear angle were found between the left and right molars of four individuals who presented anomalies in the position, shape, and depth of the occlusal surface of the molars. The findings in these individuals illustrate the importance of conducting further studies of these paleopathologies and their relationship with the feeding habits of these proboscideans; also, the analysis of dental mesowear should be supplemented with other approaches.

Interspecific competition in ictitheres (Carnivora: Hyaenidae) from the Late Miocene of Eurasia

The present paper deals with the ecomorphological characteristics of two sympatric species of ictitheres: Ictitherium viverrinum Roth & Wagner, 1854 and Hyaenictitherium wongii (Zdansky, 1924) from the Late Miocene of the Eastern Mediterranean. These two species represent different taxonomic groups with allegedly distinct ecological roles. The values of 11 ecomorphological proxies were calculated using cranial and dental elements, in order to make an extensive comparison between them (body mass, bite force, canines’ and incisors’ bending strength, endocranial volume, relative rostral width, dental mesowear, intercuspid notches and carnassial vs grinding surfaces). The proxies show similar results for both species, pointing out that they had a similar ecological niche in the Late Miocene ecosystems. Carnivorans are usually in the top of the food chain, so the existence of two ecologically similar species in the same spatiotemporal range results in interspecific competition. This explains the geographical distinction of the two species with several localities being dominated by only one of the two (e.g. Samos for Hyaenictitherium Kretzoi, 1938 and Pikermi for Ictitherium Wagner, 1848). The reason for the prevalence of each genus can be associated with their postcranial morphology, as Hyaenictitherium has been proposed to be better adapted to chase hunting, because of its longer limbs, while Ictitherium is characterized by shorter and stouter limbs.

Dental mesowear and microwear for the dietary reconstruction of Quaternary Southeast Asian serows and gorals

Serows and gorals (Bovidae, Caprinae) are emblematic antelopes distributed in Southeast Asia. They all are nearly threaten or vulnerable species nowadays despite having a more widespread distribution during the Pleistocene. Fossils of three native caprine species, i.e., a Sumatran serowCapricornis sumatraensis, Chinese goralNaemorhedus griseus, and Himalayan goralNaemorhedus goral, were recovered from four Pleistocene paleontological and archeological sites in Thailand, namely Pha Bong, Khok Sung, Tham Wiman Nakin, and Tham Lod Rockshelter. To investigate dietary changes of these Southeast Asian serows and gorals through the Quaternary, differences in feeding habits and habitat preferences between the Pleistocene and extant populations were examined using the hypsodonty index (HI) together with the mesowear II method and the dental microwear texture analysis (DMTA). The HI and mesowear-II results showed that Pleistocene and extant caprines were mixed feeders. For the Pleistocene caprine populations, the DMTA results suggested more browsing signals forC. sumatraensisthan bothNaemorhedusspecies that were mixed feeders similar to their extant populations. The DMTA demonstrated a considerable dietary overlap among the Pleistocene sympatric caprine populations. The dental microwear results also revealed that the extantC. sumatraensisis a leaf-dominant browser, while the extantN. griseuspossibly feeds on seeds or tough food items. These data combined with previous stable carbon isotope analyses reinforce the idea that the restricted ranges of habitats for these extant serow and goral populations have possibly been driven by the Holocene climatic and environmental changes as well as the negative effects of human activities.

Dietary ecology of Reduncini (Bovidae) from the Shungura Formation, Lower Omo Valley, Ethiopia

The Shungura Formation (Lower Omo Valley, Ethiopia) constitutes one of the most complete stratigraphic and paleontological records for the Plio-Pleistocene of eastern Africa and has yielded a large collection of fossil bovids, in which the most abundant tribe is Reduncini (waterbucks, kobs, and relatives). We used a multi-proxy approach to precisely reconstruct the diet and habitat preferences of Shungura reduncins to better understand of the environmental conditions that prevailed during the Plio-Pleistocene in the Lower Omo Valley. We compared the dental microwear texture analyses and the dental mesowear analyses for fossil samples dating to between 3 Ma and 1.7 Ma. We show that reduncins from the Shungura Formation had a diet dominated by browse at around 2.8 Ma, had diets ranging from browsing to mixed feeding from 2.8 Ma to 2.3 Ma, and consumed far more graze around 2.3 Ma and 1.8 Ma. Our study highlights the benefits of a multi-proxy approach to dietary reconstruction and how each dietary proxy can be leveraged to offer a slightly different, complementary perspectives on the ecology of fossil organisms. • Dental mesowear and microwear texture analyses were applied to Plio-Pleistocene reduncins. • They had diets ranging from browsing to mixed feeding from 2.8 Ma to 2.3 Ma. • They were more engaged in grazing around 2.3 Ma and 1.8 Ma. • Multi-proxy approaches are needed to precisely determine the diets of fossil organisms.

Middle Pleistocene Variations in the Diet of Equus in the South of France and Its Morphometric Adaptations to Local Environments

Equus is a very sensitive genus which has expanded over a large area and lived in Europe despite the climatic instability of the Pleistocene. Its persistence and abundance are helpful in understanding and describing environmental and climatic regional parameters. In this study, we present the result of dental mesowear and microwear analysis and post-cranial skeleton biometry on Equus populations located in two regions in the South of France from ten sites, corresponding to twelve assemblages dated from MIS 12 to MIS 5. The areas refer to two major climatic zones: the oceanic or subcontinental climate for the South West of France, and the Mediterranean for the South East. The first objective of this study is to integrate and compare biometric data, dental wear, and other already-published environmental proxies. The goal is to discuss the validity of horse body shape adaptations on a small geographical scale. The second objective is to describe the impact of environmental features on the horse population through time in the two regions. We observe that the Equus diet was quite diverse, according to microwear analysis which shows adaptations according to seasonal variations. However, they remained mostly grazers over a long period of time. Estimated body mass of Equus in the localities studied here varies from a mean of 468 up to a mean of 570 kg, but these variations failed to be correlated with the diet, the climatic period, or the geographical position of the horse population, probably because of the sample size or the restricted time-span or geographical scale. However, the conformation of the metapodials and the width of the third phalanges may have been linked with environmental and behavioural parameters. The width of the third phalange may be correlated with the recurrence of the snow cover, while the robustness of the metapodial co-occurs with a humid climate. Also, diet may influence the conformation of the bones, since the tall and slender horses seem to be preferentially grazers all year long and seasonally browser horses are tall and robust. Seasonally mixed-feeder horses, all coming from the Mediterranean area, were found to be smaller, perhaps in relation to a less productive environment. The correspondence of the dietary and morphometrical data could suggest high pressure on the horse population, which caused rapid body adaptation. Thus, the combination of these different proxies allows us to suggest more accurate large mammal paleoenvironmental reconstructions.

The diet of early birds based on modern and fossil evidence and a new framework for its reconstruction.

ABSTRACTBirds are some of the most diverse organisms on Earth, with species inhabiting a wide variety of niches across every major biome. As such, birds are vital to our understanding of modern ecosystems. Unfortunately, our understanding of the evolutionary history of modern ecosystems is hampered by knowledge gaps in the origin of modern bird diversity and ecosystem ecology. A crucial part of addressing these shortcomings is improving our understanding of the earliest birds, the non‐avian avialans (i.e. non‐crown birds), particularly of their diet. The diet of non‐avian avialans has been a matter of debate, in large part because of the ambiguous qualitative approaches that have been used to reconstruct it. Here we review methods for determining diet in modern and fossil avians (i.e. crown birds) as well as non‐avian theropods, and comment on their usefulness when applied to non‐avian avialans. We use this to propose a set of comparable, quantitative approaches to ascertain fossil bird diet and on this basis provide a consensus of what we currently know about fossil bird diet. While no single approach can precisely predict diet in birds, each can exclude some diets and narrow the dietary possibilities. We recommend combining (i) dental microwear, (ii) landmark‐based muscular reconstruction, (iii) stable isotope geochemistry, (iv) body mass estimations, (v) traditional and/or geometric morphometric analysis, (vi) lever modelling, and (vii) finite element analysis to reconstruct fossil bird diet accurately. Our review provides specific methodologies to implement each approach and discusses complications future researchers should keep in mind. We note that current forms of assessment of dental mesowear, skull traditional morphometrics, geometric morphometrics, and certain stable isotope systems have yet to be proven effective at discerning fossil bird diet. On this basis we report the current state of knowledge of non‐avian avialan diet which remains very incomplete. The ancestral dietary condition in non‐avian avialans remains unclear due to scarce data and contradictory evidence in Archaeopteryx. Among early non‐avian pygostylians, Confuciusornis has finite element analysis and mechanical advantage evidence pointing to herbivory, whilst Sapeornis only has mechanical advantage evidence indicating granivory, agreeing with fossilised ingested material known for this taxon. The enantiornithine ornithothoracine Shenqiornis has mechanical advantage and pedal morphometric evidence pointing to carnivory. In the hongshanornithid ornithuromorph Hongshanornis only mechanical advantage evidence indicates granivory, but this agrees with evidence of gastrolith ingestion in this taxon. Mechanical advantage and ingested fish support carnivory in the songlingornithid ornithuromorph Yanornis. Due to the sparsity of robust dietary assignments, no clear trends in non‐avian avialan dietary evolution have yet emerged. Dietary diversity seems to increase through time, but this is a preservational bias associated with a predominance of data from the Early Cretaceous Jehol Lagerstätte. With this new framework and our synthesis of the current knowledge of non‐avian avialan diet, we expect dietary knowledge and evolutionary trends to become much clearer in the coming years, especially as fossils from other locations and climates are found. This will allow for a deeper and more robust understanding of the role birds played in Mesozoic ecosystems and how this developed into their pivotal role in modern ecosystems.

Quantitative Dental Mesowear Analysis in Domestic Caprids: a New Method to Reconstruct Management Strategies

Dental mesowear is a widely used tool in archaeology and palaeontology for the reconstruction of the overall diet of mammals. This method is based on the characterisation of the height and relief of dental cusps, as they vary according to diet. The use of this method on domestic ungulates presents limitations because (1) currently, very few reference frameworks are available, and (2) the qualitative categorisation of cusps limits our observations and interpretations. In this work, we introduce the analysis of quantitative dental mesowear, based on the measurement of the angle and height of cusps from photographs. The use of this method on 26 present-day domestic sheep with two different feeding strategies showed very significant differences: the group with a dominant rangeland diet has high cusps with acute angles, and the group with a dominant grassland diet has lower cusps with obtuse angles. This method has been compared with the traditional technique of mesowear score, which consists in the qualitative categorisation of cusps into seven categories. However, the analysis showed that mesowear score is more prone to observer error than quantitative mesowear. In addition, quantitative mesowear better reflects the variability in dietary behaviours of extant sheep since observations are not limited into seven categories. To test quantitative mesowear in archaeological samples, we analysed caprine mesowear at two Iron Age sites (sixth-fifth centuries BC) from the northeast of the Iberian Peninsula: Empúries and Ullastret. The results show that caprids at the Ullastret site have a slightly more abrasive diet than at Empúries, which is consistent with data obtained from dental microwear in previous work. Overall, we show the potential of this technique, which can be combined with traditional techniques, to distinguish past caprine feeding strategies.

Multiproxy paleoenvironmental reconstruction of Early Pleistocene sites from the Olteţ River Valley of Romania

The Early Pleistocene is recognized as a time of major global climatic and environmental change, including increasing aridity, significant spread of grasslands, and substantial faunal turnovers and dispersals. Importantly, this is the first time hominins are found in Eurasia. Reconstructing the types of environments that existed during this time is imperative for understanding mammalian, including hominin, dispersal patterns relative to climatic change. One proposed dispersal corridor across Europe is the Danube River. Here we characterize the 2.2 to ~1.1 million years ago (Ma) paleoenvironments surrounding one of the tributaries to the Danube, the Olteţ River, in southern Romania using a multiproxy approach, including taxonomic uniformitarianism, dental mesowear, dental microwear, enamel stable isotope (carbon and oxygen), and coprolite/palynology analyses, and compare our results to other penecontemporaneous Eurasian sites. Older sites from this region, Grăunceanu and La Pietriş, both dating to 2.2–1.9 Ma, are reconstructed as being primarily open, though with some nearby woodlands and significant water resources. Fântâna lui Mitilan, which is younger (1.8–1.1 Ma), is reconstructed as slightly more closed, though still relatively open in nature. These results are similar to reconstructions for other Early Pleistocene Eurasian sites, including ones with and without hominins, suggesting that hominins were likely not inhibited from dispersing across Eurasia due to environmental constraints at this time.

Dietary stability inferred from dental mesowear analysis in large ungulates from Rancho La Brea and opportunistic feeding during the late Pleistocene

The Rancho La Brea locality is world famous for asphaltic deposits that trapped and preserved late Pleistocene megafauna over the last 50,000 years. This wealth of paleontological data allows for detailed investigation into paleoecological changes through the last glacial maximum into the Holocene. Here, we used dental mesowear analyses to infer dietary behavior in Bison antiquus, Equus occidentalis, and Camelops hesternus from five deposits (“pits”) spanning the latest Pleistocene: pits 77, 91, 13, 3, and 61/67. Mesowear was compared among pits for each taxon and discriminant function and posterior probability analyses were conducted using a modern dataset to predict dietary categories at Rancho La Brea. Published mesowear scores from late Pleistocene Bison, Equus and Camelops from other localities were included in the discriminant function and posterior probability analyses to assess dietary variability among regions. Mesowear for each taxon did not differ among pits. Posterior probabilities and discriminant function analyses recovered E. occidentalis as a strict grazer with B. antiquus and C. hesternus recovered as mixed feeders. The stability of mesowear scores through the latest Pleistocene suggests average diets of these herbivores did not significantly change at Rancho La Brea. This is in contrast to documented changes in climate and flora proxies of southern California. However, it is unclear whether these proxies are representative of climate and floral changes at Rancho La Brea. Mesowear scores from late Pleistocene populations of Equus, Bison, and Camelops indicate little variability in diet in Equus, modest variability in Bison, and high variability in Camelops. These analyses suggest large ungulates may have been more opportunistic in their feeding strategies and highlights the need for using multiple proxies to clarify dietary behavior of herbivores

The skeleton of a straight‐tusked elephant, Palaeoloxodon antiquus (Falconer and Cautley, 1847) from Selsey, England, and growth and variation in Palaeoloxodon of the European Pleistocene

ABSTRACTA partial skeleton of straight‐tusked elephant (Palaeoloxodon antiquus) excavated at Selsey beach (Sussex, UK) in 1961 is one of very few from Marine Isotope Stage 7 (MIS 7), ca. 240–200 ka, in Europe. Dental morphometrics, including X‐ray micro‐computed tomography, confirms the species identification. Age determination through dental wear and skeletal morphology, sex determination through pelvic anatomy, and body‐size measurements, together identify the individual as a female of approximately 30 years old with a live shoulder height of ca. 3 m and a body mass of ca. 5 t. Dental mesowear indicates mixed feeding with a significant proportion of grass, indicating selective feeding in a predominately forested environment. Although taphonomic conclusions are limited by the nature of the excavation, identification of 107 recovered skeletal elements indicates predominant preservation of the right side of the animal, suggesting death or burial on the right side in a shallow, slow‐moving freshwater environment, with possible removal of other elements by scavenging or decay. Combining the Selsey data with 29 comparative skeletons from across Europe, we demonstrate the validity of pelvic proportions for determining sex and provide a graphical representation of variation and growth rate in males and females of this species.

Impact of Early and Middle Pleistocene major climatic events on the palaeoecology of Southern European ungulates

ABSTRACT The Early and Middle Pleistocene were characterised by two major climatic events: the onset of the Quaternary glaciations and the Early-Middle Pleistocene Transition (EMPT) with glacial cycles changing their periodicity. The present study reviews recent research on the palaeoecological adaptations of Pleistocene ungulates from Mediterranean Europe following these global climatic changes, through an examination of dental wear patterns and hypsodonty indices of 27 fossil taxa from 4 key localities. Ungulates from Coste San Giacomo (2.1 Ma) adopted a wide range of feeding behaviours suggesting the presence of heterogeneous environments in the region. Following the gradual deterioration of climatic conditions and drier habitats ungulates display narrower diet ranges with no incidence of obligated browsers as attested at Olivola (~1.8 Ma). The diffusion of open habitats from the Early Pleistocene onwards is also reflected by the reduction of brachydont taxa. Discrepancy between dental mesowear and microwear patterns of Vallparadís Estació (~1.0–0.6 Ma) and Fontana Ranuccio (0.4 Ma) ungulates points to an increase in seasonality during the EMPT and after its consolidation. All examined taxa display dietary plasticity through the Early and Middle Pleistocene with even specialised groups, such as equids, showing a certain flexibility in their diet.

Palaeodietary traits of large mammals from the middle Miocene of Gra\u010danica (Bugojno Basin, Bosnia-Herzegovina)

Recent excavations at the Gračanica 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 Gračanica.

Climate and ecology of the palaeo-Agulhas Plain from stable carbon and oxygen isotopes in bovid tooth enamel from Nelson Bay Cave, South Africa

We measured δ13Cenamel and δ18Oenamel in 213 archaeological bovid teeth from Nelson Bay Cave (NBC), spanning the last 22 ka. We also recorded dental mesowear (occlusal relief [high versus low] and cusp shape [sharp, round, or blunt]) of all maxillary first and second molars from NBC. We use these values to explore glacial/interglacial shifts in bovid palaeoecology and to reconstruct aspects of the climate and environment of the Palaeo-Agulhas Plain. Our results indicate that at the time of the Last Glacial Maximum (LGM), there was a significantly greater proportion of C3 (winter-rainfall) grasses, although some C4 (summer rainfall) varieties were present. This conclusion is strengthened by correction for lower pCO2 at the LGM, leading to reduced carbon isotope fractionation in C3 photosynthesis. Terminal Pleistocene and Holocene grazers show a stronger C4 signal. Our findings are consistent with an eastwards extension of winter rainfall at the LGM, as proposed by some previous researchers. Beyond the broad distinction between browsers and grazers, δ13C values reflect species-specific dietary preferences. δ18O is more positive in browsers than grazers, probably due to their deriving a significant proportion of their water intake from evaporatively enriched leaf water. δ18O values do not show significant changes through time. The location of Nelson Bay Cave on the present-day interface between temperate and tropical weather systems means that this area is sensitive to past shifts in the relative importance of these systems. These findings therefore contribute to the reconstruction of past Southern Hemisphere climate dynamics on a glacial/interglacial time scale.

Dental Microwear and Mesowear of the Microtus Voles Molars before and after Experimental Feeding of Owls.

In small mammals, the degree of micro- and mesowear of molars depends on the feed hardness, abrasiveness, and some other characteristics. Analysis of micro- and mesorelief of the paleontological material is used for reconstruction of some animal diet parameters. Small mammals pass through a series of complex transformations on the way from the objects of biocenosis to paleontological objects. Bone remains underwent transformations during accumulation and fossilization. In particular, bone remains from ornithogenous deposits were exposed to the bird digestive system elements. We have experimentally studied changes in some parameters of the narrow-headed vole (Microtus gregalis) molars derived from the owl pellets. Comparison of the same samples before and after exposure to the digestive system of the polar owl (Nyctea scandiaca) and eagle owl (Bubo bubo) showed that the tooth enamel microrelief undergoes serious changes and therefore, provides no information on the intravital diet of voles. A different degree of preservation of the characteristics of the mesorelief was shown. Depending on this, an assessment of their applicability to paleoreconstructions was given.

Paleoecological implications of dental mesowear and hypsodonty in fossil ungulates from Kanapoi

The Pliocene site of Kanapoi is key to our understanding of the environmental context of the earliest species of Australopithecus. Various approaches have been used to reconstruct the environments of this site, and here we contribute new data and analyses using mesowear and hypsodonty. The dental traits of 98 bovids, suids and rhinocerotids from Kanapoi were analyzed using these proxies. Results indicate that most of the animals analyzed had a relatively abrasive diet. Bovids in the assemblage incorporated more grass into their diet than do modern species of the same tribe or genus. Although Pliocene Kanapoi likely had complex environments, our analysis indicates that grassy habitats were a dominant component of the ecosystem, a conclusion that supports the results of previous investigations of the paleoecology of the site.

Effects of climate on dental mesowear of extant koalas and two broadly distributed kangaroos throughout their geographic range.

Dental mesowear analysis can classify the diets of extant herbivores into general categories such as grazers, mixed-feeders, and browsers by using the gross wear patterns found on individual teeth. This wear presumably results from both abrasion (food-on-tooth wear) and attrition (tooth-on-tooth wear) of individual teeth. Mesowear analyses on extinct ungulates have helped generate hypotheses regarding the dietary ecology of mammals across space and time, and recent developments have expanded the use of dental mesowear analysis to herbivorous marsupial taxa including kangaroos, wombats, possums, koalas, and relatives. However, the diet of some of the most ubiquitous kangaroos (e.g., Macropus giganteus) along with numerous other species cannot be successfully classified by dental mesowear analysis. Further, it is not well understood whether climate variables (including precipitation, relative humidity, and temperature) are correlated with dental mesowear variables including various measures of shape and relief. Here, we examine the relationship between dental mesowear variables (including traditional methods scoring the sharpest cusp and a new potential assessment of multiple cusps) and climate variables in the grazers/mixed feeders Macropus giganteus and Macropus fuliginosus, and the obligate browser Phascolarctos cinereus. We find that dental mesowear of mandibular teeth is capable of differentiating the dietary habits of koalas and the kangaroo species. Furthermore, both Macropus giganteus and Phascolarctos cinereus exhibit mesowear correlated with mean minimum temperature, while Macropus fuliginosus dental mesowear is unaffected by temperature, despite significant differences in mean minimum and mean maximum temperature across their distribution (and in the specimens examined here). Contrary to expectations that individuals from drier regions would have blunter and lower relief teeth, dental mesowear is unrelated to proxies of relative aridity—including mean annual precipitation and relative humidity. Collectively, dental mesowear in these marsupials is related to feeding behavior with increased wear in cooler regions (in Macropus giganteus and Phascolarctos cinereus) potentially related to more or different food resources consumed.