Biogeologie

PhD Projects

Current PhD Projects

Valentina García-Huidobro

Impact of Megafauna Demise in South American Ecosystems during the Late Quaternary

My doctoral research centers on studying the ecological effects of the extinction of megafauna on South American ecosystems in the Late Quaternary period. The loss of megafauna, such as giant sloths, had a profound impact on the structure and functioning of these ecosystems by disrupting predator-prey relationships and plant communities. By analyzing stable isotopes from fossil bones, I aim to track the diet and food web dynamics of these mammals and how the decline of megafauna has impacted not only individual species but also the overall biodiversity of the region. This research is part of the Senckenberg Society for Natural Research's Anthropocene Biodiversity Loss project.

 

Manhon Mouhat Bourquard

From Ornaments to Ecosystems: Human-Mammoth Interactions

I study the interactions between humans and mammoths in the Swabian Jura between 60,000 and 30,000 years ago. To understand how humans and mammoths influenced each other, both ecologically (diet, mobility, environment) and culturally (use of bones and ivory for tools, ornaments, and art).  I’m particularly interested in the isotopic aspect of this project. Through isotopic analyses, we can explore the ecological niche, diet, and mobility of mammoths. By comparing the isotopic signatures of several animal species, it becomes possible to understand how they interacted with their environments and with each other. This approach helps us reconstruct the structure and dynamics of past ecosystems and better understand the factors that led to the decline of mammoths, whether it was mainly due to climate change, human hunting pressure, or a combination of both. It also provides valuable clues about how humans used and transported mammoth remains.

 

Isabella Vasconcellos Goulart

Titel: tba

Abstract: tba

 

Nathanael Drüeke

Geobiochemical Controls on Collagen Isotopic Spacing Between Bone and Dentin in Modern and Ancient Animals

Abstract: tba

 

Finished PhD projects

Emily Milton (2025)

A Multi-Isotopic Approach to Human-Environment Dynamics in the Central Andes, Peru

The western Central Andes of South America comprise a mosaic of landscapes shaped by gradients in elevation, latitude, and climate. Archaeological evidence shows that ecological diversity has long sustained human and animal communities, and that interconnected environments have been a defining feature of Andean society from the Pleistocene to the present. Yet this same ecosystem diversity complicates the application of stable isotope analysis to archaeological questions. This dissertation examines the theories, methods, and best practices of isotopic research in archaeological contexts through four case studies from southern Peru. The first article evaluates the use of stable oxygen and hydrogen isotopes to track mobility in western Peru, identifying key limitations and emphasizing the need for alternative tracers. The second develops a deep-time faunal baseline for the high Andes, demonstrating how stable sulfur can more securely distinguish mobility among ecozones. The third analyzes new carbon, nitrogen, and sulfur data from Late Holocene marine birds and maize, exploring how human-introduced marine inputs complicate both paleodietary reconstructions and radiocarbon chronologies. A fourth engages social theory to assess the methodological and ethical significance of environmental baselines for interpreting isotopic data from human remains.  Finally, a concluding public-facing article considers the enduring importance of Andean resources for human communities and the climate crisis confronting these landscapes today. Together, these studies advance isotopic approaches in the Central Andes by addressing equifinality, refining baseline datasets, and foregrounding the social and theoretical dimensions of the archaeological sciences.

Jules Walter (2025)

Origin, diversity and evolution of the most common crocodylians of Europe in the Paleogene greenhouse context

Crocodylia is an iconic reptile vertebrate group whose extant representatives inhabit most of the continental land masses. Modern Europe is a notable exception, as no crocodyliform populations are found in this region of the world, which is greatly contrasting with the past biogeographical history of the group. The early Cenozoic, specifically, shows an exceptionally diverse crocodyliform fauna mainly dominated by alligatoroids. Morphological disparity, complex biogeography or even stratigraphically young age of the earliest-branching forms have been difficult to reconcile with consistently inferred phylogenetic relationships to alligatorids, an otherwise freshwater and small-bodied group in the Paleogene. The European putative alligatoroid genus Diplocynodon is recognised as the most common and best sampled crocodyliform in the Paleogene of Europe, as demonstrated by the extensive fossil record spread across multiple occurrences throughout the Cenozoic. This record hints at an exceptional survivorship of the genus from the late Paleocene to the middle Miocene, that perplexes the comprehensive investigation of the taxon systematics and taxonomy, indication of an overdue revision. The thesis presents an expanded phylogeny with increased spatiotemporally coherence that reinterprets Diplocynodon spp. (recovered closely related to the North American Borealosuchus) as well as the North American Deinosuchus spp. and Leidyosuchus canadensis as stem-group crocodylians. The novel topology elucidates the evolution of osmoregulation in Crocodylia and its close relatives by inferring plesiomorphic saltwater tolerance for Deinosuchus and the crown-group, and secondary loss already in stem-group alligatorids. Divergence of Alligatoroidea coincided with extreme mid-Cretaceous sea level highs and the distribution of Deinosuchus across the American Western Interior Seaway can be best explained by marine dispersal. Phylogenetic body-length analysis using a head-width proxy reveals phyletic dwarfism early in alligatoroid evolution and a reasonable total length estimate for the most complete specimen of Deinosuchus riograndensis. Gigantism in crocodyliforms is suggested as being correlated with high-productive extensive aquatic ecosystems in the present and in the past. The second and third chapters tackle the complex ingroup taxonomy of Diplocynodon. The diagnoses of currently accepted Diplocynodon species commonly include shared and/or irreproducible characters, hampering specific delimitations. Based on the review of all currently known species, the first taxonomic revision of the group since its inclusion in modern phylogenetic works is presented. An identification key to assist researchers with the identification of the valid species is additionally provided. Furthermore, the present work quantitatively reviews the state of the entire fossil record of Diplocynodon (based on two openly available databases) and discusses the waste-basket status of the taxon with respect to better taxonomical practices. Within Diplocynodon, the Eocene species Diplocynodon darwini Ludwig, 1877 has the largest sample in the Paleogene period, consisting of tens of complete well-preserved specimens, but yet critically lacks a detailed osteological description. The taxon is here redescribed for the first time based on type specimens collected 150 years ago and abundant excellently preserved material from the Messel and Geiseltal Konservat-Lagerstätten. Insights into the intraspecific variation in the taxon are provided in a detailed morphological description on the skeletal elements, including ontogenetic variation in temporally restricted populations. The complex ingroup taxonomy of Diplocynodon is furthermore explored and discussed through a review of previously published and newly retrieved phylogenies.

Gustavo Darlim (2024)

Phylogeny and divergence ages in Crocodylia: implications for crown-clades and paleobiogeography

Crocodylia is represented by semi-aquatic ambush predators that inhabit freshwater and estuarine environments in the tropical and subtropical regions of the globe. Composed by 25 extant recognized species in three main lineages (Crocodyloidea, Gavialoidea and Alligatoroidea), mitogenomic studies recognizes a higher diversity of crocodylians within cryptic species complexes that are otherwise unrecognizable based on morphological analyses. Extinct crocodylian species furthermore outnumber the living diversity as evidenced by a considerable fossil record extending to late Stages of the Cretaceous Period. The combination of well sampled fossil record and low extant diversity that allows comprehensive sampling for molecular data makes Crocodylia a good model clade for macroevolutionary studies. In spite of phylogenetic analysis using molecular data consistently recover a common topology, paleontological studies in Crocodylia often continue to use morphology-only datasets, which in turn impacts on on the inferred phylogenetic position of many fossil taxa. Examples of topological discrepancies in Crocodylia are represented by: (i) the phylogenetic position of the Indian gharial Gavialis gangeticus represents one of the long-standing conflicts in crocodylian systematics, as phylogenetic inferences based on morphology alone places Gavialis sister to all other living crocodilians (i.e. alligators and crocodiles), whereas molecular data unite Gavialis with the false gharial Tomistoma schlegelii as a sister clade to Crocodylidae alone. These topological discrepancies in turn affects particularly taxa close to the root of Crocodylia and/or with a Gavialis-like morphology. Hence, the ambiguous phylogenetic position of basal fossil taxa may eventually lead to unreasonable selection of fossil calibrations for divergence age estimates in molecular studies, which in turn majorly affects macroevolutionary inferences in Crocodylia; (ii) Similarly, topological conflicts are furthermore observed in the crown clades of Alligatoridae (Caimaninae, Alligatorinae), as incomplete fossil and unstable phylogenies of extinct caimanines hamper a reconstruction of early evolution in the clade, in addition to poorly justified selection of fossil as calibration in molecular studies overestimate the origin of total and crown-Caimaninae; and finally (iii) the origin of the Chinese alligator (A. sinensis) is considered a biogeographical puzzle, as the timing and climatic context of Alligator dispersal from North America to Asia is poorly constrained: paleontological evidence and molecular estimates for the split between A. sinensis and its only closest living relative A. mississippiensis (American alligator) are in conflict; Alligator fossils have never been recovered in the stem-lineage of A. sinensis; and Alligator fossil species from Asia have never been included into a phylogenetic framework. In the present thesis, in order to investigate the three abovementioned conflicts in crocodylian systematics, I explore (I) the effects of the use of molecular data on the position of fossil taxa close to the root of Crocodylia; (II) the phylogeny of Caimaninae as an extensive reappraisal of the position of fossil taxa in addition to provide well-justified fossil calibrations for the total and crown-groups; (III) the evolution of Alligator focusing on expanding the dataset by describing a new Alligator species, Alligator munensis, and by including fossil species from Asia into a phylogenetic context, contributing to the understanding of Alligator intercontinental dispersal. A series of methodologies were explored in order to meet the objectives, including traditional alpha-taxonomy descriptions, use of computed tomography, extensive literature review, phylogenetic analysis under Maximum Parsimony, undated Bayesian inference and total evidence tip dating. The studies composing this thesis contribute significantly for the comprehension crocodylian systematics by providing time-scaled phylogenies, highlighting the importance of DNA-informed phylogenetic inference for basal crocodylian relationships and divergence age estimates together with the use of well-justified fossil calibrations, and contributes to the understanding of Alligator evolution and biogeography.

Felix Augustin (2024)

Latest Cretaceous Vertebrates from the Hateg Basin, Romania

The Late Cretaceous was a crucial time for the evolution of life on land, and despite its importance, this period is incompletely understood in many places around the world. The uppermost Cretaceous continental deposits of the Haţeg Basin in western Romania have yielded one of the richest and most diverse vertebrate assemblages of Europe, thus being of paramount importance for understanding European Late Cretaceous ecosystems. Although the Haţeg Basin looks back on a research history of more than 120 years, many open questions about the latest Cretaceous vertebrate assemblages remain. This includes, in particular, their diversity, their phylogenetic and biogeographical relationships, as well as palaeoecological aspects. In order to assess these questions, four key specimens were examined for this thesis, a partial turtle skeleton, two ornithopod braincases and one partial skull of a rhabdodontid dinosaur. The first specimen can be confidently referred to the Dortokidae, a European endemic clade of basal Pleurodires. It is morphologically similar to the genus Dortoka but differs significantly from all previously described species of that genus and thus is assigned to a new species, Dortoka vremiri. Phylogenetic analyses recovered the new taxon in a sister-group relationship with a Paleocene dortokid from western Romania, indicating local survival of the lineage across the K/Pg extinction, as opposed to subsequent immigration, as well as the presence of two distinct dortokid lineages, an eastern and a western European one. Additionally, it was possible to demonstrate that the new species occupied a different ecological niche than the only other sympatric turtle taxon from the Haţeg Basin described before, Kallokibotion bajazidi. The two ornithopod braincase specimens have previously been referred to the rhabdodontid Zalmoxes, although they differ markedly from other braincase specimens of that genus described before. A detailed comparison with basal and more derived ornithopods demonstrated that the peculiar morphology of these two specimens is exclusively found in hadro-sauroids. Therefore, the two specimens are re-assigned to the basal hadrosauroid Telmatosaurus. The final specimen examined is a partial skull that resembles rhabdo-dontid dinosaurs. Despite these similarities, the specimen differs considerably from all other rhabdodontid skulls reported thus far and shows a unique and highly auta-pomorphic anatomy, and therefore, it is assigned to a new genus and species, Transylvanosaurus platycephalus. Two sets of phylogenetic analyses placed the new taxon within Rhabdodontidae but were unable to resolve the in-group relationships. Based on the high degree of similarity between Transylvanosaurus and Rhabdodon from southern France, a particularly close relationship between those taxa is suggested, which indicates a more complex biogeographical history than previously recognised. In addition, Transylvanosaurus differs widely from the sympatric rhabdo-dontid Zalmoxes in its skull proportions, indicating a certain degree of niche partitioning between the two genera. The results of this dissertation show that the alpha-level taxonomic diversity of certain groups was higher than previously thought. Moreover, the phylogenetic relationships of the new taxa indicate more complex biogeographical histories than reconstructed before and differential distribution patterns for different vertebrate groups. Finally, it was possible to detect some degree of niche partitioning between the members of the vertebrate groups.

 

 

Sophie Habinger (2023)

Paleoecology and Paleoenvironments of Early Anthropoid and Hominoid Primates in Southeast Asia

The Cenozoic fossil formations of Southeast Asia document a highly dynamic period in mammalian evolution. Many clades of modern mammals originated from this biogeographic region or experienced important radiations there including anthropoid primates and pongines. Here, I want to characterize the ecological and environmental contexts in which these developments took place, specifically regarding palaeoseasonality, vegetation structure, diet and niche partitioning. To do so, I focused on two fossil mammal assemblages from the Central Basin of Myanmar representing two key time periods in the evolutionary history of primates. The greenhouse world of the middle Eocene Pondaung Fm. is a window to explore the ecosystem dynamics in the faunal assemblage of a habitat, which sustained a large number of different early anthropoid primates as well as a diverse fauna of herbivorous mammals. Previous studies focused on climate and vegetation of the Pondaung environment. While I also worked on aspects of paleoseasonality and vegetation structure, my focus lay on the structure of microhabitats across the different localities of the Pondaung Fm. and their use by the different taxonomic groups. Based on this work, I could infer ecological flexibility for at least some of the anthropoid primate species, based on their occurrences in different microhabitats. The second focal point of my work on the Pondaung fauna were the anthracotheres and a detailed reconstruction of their paleoecology and the competition dynamics between the five species. With the second mammal assemblage, we want to address open questions surrounding the evolutionary ecology of Ponginae in Southeast Asia. Today, there only is one genus (Pongo), whose geographical distribution is highly restricted to the islands of Borneo and Sumatra. From the Miocene to the Pleistocene however, species diversity and geographic range were much more extensive. The fossil record of pongines spans the area from Turkey to southern China. The late Miocene Irrawaddy Fm. is an example for the habitat of the sister-group of extant orangutans, Khoratpithecus, which is represented here by the species Khoratpithecus ayeyarwadyensis. I characterized the habitat of this fossil pongine by reconstructing its paleoseasonality, vegetation structure and niche partitioning dynamics. Then focused my work on the question if there was ecological continuity in the pongine clade since the Miocene, with a comparison of the different taxa from South and Southeast Asia. For my studies, I used to different analytical approaches to assess paleoecology and diet in these fossil mammal faunas. Here, I present the stable isotope analysis and subsequent niche modelling of the Eocene and Miocene fossil assemblages from Myanmar and the dental microwear texture analysis I used to get a more detailed insight into pongine evolutionary ecology with the comparison of subsistence strategies of Miocene pongines to Pleistocene and extant orangutans. With the different studies of my dissertation project I could show possibilities to push the boundaries of stable isotope niche modelling by using a different set of isotopes that are representing more general ecological characteristic of a niche rather than just trophic or dietary dimensions. I also successfully explored the application of new approaches with the modelled isotopic niches that previously were only used by stable isotope ecologists working on modern ecosystems to geological time periods. One example is the evaluation of competition potential dynamics in the anthracothere assemblage from the Pondaung Fm. The work on the Selenka orangutans was another way in which I could bridge the gap between palaeontology and ecologists and biologists working on extant primate faunas in providing a data set that opens new research directions in both fields.

Anne Kremmer (2023)

Socioeconomic Differences and Secular Changes in Living Conditions in Late-Medieval and Postmedieval Luxembourg City

Since its first mention in 963AD, the city and especially the fortress of Luxembourg had been growing steadily throughout the medieval times under the rule of the counts of Luxembourg. However, it is only in 1443AD, after the conquest by Philip the Good, duke of Burgundy, that the city of Luxembourg, which by then had become one of the strongest fortresses in western Europe, was finally caught between the fronts of the major political forces of the time. From then on until the demolition of the fortress in the mid-19th century, life in Luxembourg City had been dominated by foreign occupations as well as several sieges and wars. In order to assess the impact these times of political unrest had on the population of the city, 391 individuals buried inside the cloister and on the cemetery grounds of a Franciscan friary which was in use from ~1255AD until 1778AD, were analysed. The cemetery, located beneath a town square nowadays called “Knuedler”, was excavated in 3 campaigns between 2008 and 2018. 14C analyses and evaluation of archaeological data allowed to identify two main burial phases: an older one dating from the mid-14th to the mid-17th century and a younger one dating from the mid-17th century to the cemetery’s dissolution in 1778AD. The aim of this study is to investigate whether there are detectable changes in physical activity, health, and diet, and thus in living conditions over time and amongst different socioeconomic groups, represented by the cloister and cemetery burials. These questions were addressed by examining palaeodemographic parameters, stature and growth, markers of physical activity, diseases and indicators of diet and nutritional status and by comparing the results to contemporaneous rural, urban and monastic sites. The excess of males in the Knuedler sample, especially among cloister burials, suggests that at least the latter did not represent a biologically grown population. Likely, the resident friars were also buried within the monastic precinct. The high life expectancy, low child mortality and mean age at death can also be taken as indicators of good health and nutritional status, as they suggest that the majority of individuals survived well into adulthood. The stature of the individuals under study reached that of average medieval and postmedieval urban centres and no stunting or delayed growth could be detected during childhood. Furthermore, the low incidence of infectious and metabolic diseases and non-specific stress markers indicate that the individuals buried in the Knuedler friary generally did not experience significant nutritional deficiencies. Altogether, this suggests that, despite the historically documented overcrowding of the city and regular food shortages caused by sieges, wars and epidemics, the inhabitants of Luxembourg City buried in the Knuedler friary were mostly exempt of those hardships. Furthermore, no relevant changes in these health indicators over time could be noted, but discrepancies between the burial locations suggest that those buried within the cloister area were less exposed to infectious diseases and nutritional stress than those buried in the cemetery. Healed infectious diseases, well-aligned fractures and traumatic lesions as well as successful and unsuccessful surgical procedures can be seen as evidence for efficient medical care. The few sharp force and gunshot traumata are evidence of the impact of the wars and sieges on the population of Luxembourg City. The relatively high proportion of carious lesions and dental calculus could be indicative of a carbohydrate-rich diet with a high protein content, whereas the relatively low dental abrasion suggests that the diet was primarily composed of softer foods with few abrasive components. The results of the stable isotope analyses suggest a diet based primarily on terrestrial C3 plants and animals that fed on them. Differences between the burial locations suggest that individuals from the cloister had less abrasive and cariogenic substances in their diet and consumed either more meat or supplemented their diet periodically with marine or freshwater resources. No noteworthy shift in dietary patterns could be detected between the burial phases regarding the stable isotope results but a decrease in attrition intensity suggests that the texture of the diet softened over time, likely due to improved food production methods. The generally high frequency of dental pathologies such as caries, calculus and periodontopathies are indicative of a general lack of oral hygiene, a pattern observed also in the majority of the archaeological comparative populations. The study of enamel hypoplasia formation ages, first onset of caries and attrition as well as the combination of two stable isotope methods made it possible to narrow down the weaning age period to 1.5-3 years. As mechanical loading can leave traces on bones, the examination of bilateral asymmetry, bone robusticity, entheseal changes and degenerative joint disease can inform about the intensity of physical activity a population is subjected to. These markers of physical activity showed only light to moderate degrees of expression and their intensity was correlated with age and sex and not with burial location or phases. This suggests that in both socioeconomic groups and in the late medieval and postmedieval times alike, these individuals were engaged in occupations that were not very strenuous. This is in line with findings of other contemporaneous urban sites and shows that their lifestyle was not as physically demanding as that of rural societies. Altogether, the results of this study paint the picture of individuals that had rather good living conditions despite the historically documented hardships, therefore likely representing a more privileged part of Luxembourg City’s society. Thus, this interdisciplinary study offers the first detailed insights into the living conditions inside one Europe’s strongest fortresses and can serve as a solid basis for further anthropological investigations.

 

Giuseppe Briatico (2022)

The palaeonvironmental context of the Early and Middle Pleistocene at Melka Kunture archaeological site (Upper Awash Valley, Ethiopia), as evidenced by stable isotope analysis

Stable isotope analysis is a well-established and powerful tool for determining valid information on paleodiet, paleoenvironment, and paleoecology (Bibi et al. 2013; Bocherens et al. 1996; Cerling et al. 2015; Lee-Thorp et al. 2010; Levin et al. 2008; Rivals et al. 2018). This method has been widely applied to Pleistocene archaeological sites in eastern Africa at medium and low altitudes (Ascari et al. 2018; Bedaso et al. 2010; Negash et al. 2020; Rivals et al. 2017; Semaw et al. 2020; Uno et al. 2018); however, the literature lacks isotopic reconstructions of ecological conditions at high elevations.  Here, are reported the carbon and oxygen stable isotope compositions (13C, 18O) of fossil teeth enamel (carbonates) from the Melka Kunture (MK) prehistoric site, located in the Ethiopian highland (~2000 m a.s.l.), in order to provide paleoenvironmental insights. The 13C/12C and 18O/16O isotopic ratios were measured on 178 fossil teeth representing a various range of taxa (Hippopotamidae, Bovidae, Equidae, Suidae, Giraffidae, and Crocodylidae) to determine the extent of the vegetation types. Collectively, 310 enamel samples (bulk and intra-tooth) were analyzed. The carbon isotopic results of hippopotamids, bovids, equids, suids, and giraffids indicate a range of foraging strategies across the pure C4 diets to mixed C3-C4 diets, with variations between ~1.95 Ma and ~0.6 Ma (Mega annum) (Early and Middle Pleistocene). In contrast, the bulk and intra-tooth carbon isotopic ratios of crocodiles suggest that these Pleistocene reptiles ate herbivores that consumed C3 plants. The intra-tooth results of hippo, equid, and suid teeth indicated C4 diets and stable water conditions during the lifetime of the sampled mammals. The isotopic data, which emphasize the presence of open space conditions such as C4 high-elevation grasslands, are consistent with pollen and phytolith analysis, indicating extended mountain grasslands, with a different abundance of mesophytic grasses, mountain forests, woodlands, and bushlands. However, it should be kept in mind that isotopic results from teeth enamel reflect the feeding strategies and the ecological behaviour of the analyzed taxa, while fossil pollen allows describing the plant types present even at a certain distance from the site, and phytolith data allow characterizing the distribution of the “on the spot” plants at the time of deposit formation. These complementary data encourage a combined approach among distinct methods that can yield more detailed paleoenvironmental and ecological insights.

Chris Baumann (2020)

Crazy like a fox? How the study of archaeological fox remains can help to understand human behavior in the Late Pleistocene of the Swabian Jura (Germany)

In many countries and fables, characteristics such as "smart" and "sly" as well as other human-like behavior have been attributed to foxes for a long time. However, is it also smart and sly to invoke foxes to prove human behavior from a long time ago?
Remains of arctic and red foxes (Vulpes lagopus and Vulpes vulpes) are known from almost every European Late Pleistocene archaeological site (about 100 to 13 kyr ago). Of particular interest in archaeological studies are their canines, found in the cave sites of the Swabian Jura (Baden-Württemberg, Germany), originating from Aurignacian (about 42 to 34 kyr ago) and Gravettian (about 34 to 30 kyr ago). The canines were perforated by early modern humans and most likely worn as pendants or ornaments on clothes. Cut marks on fox bones show that fur and meat were important as well. With my PhD thesis, I would like to explore beyond the obvious evidences the following three questions: How did Neanderthals in the Middle Palaeolithic (about 100 to 42 kyr ago) and modern humans in the Late Palaeolithic (about 42 to 14 kyr ago), hunt and use foxes? Which feeding habits did Late Pleistocene foxes follow and were they influenced by Neanderthals or modern humans, for example by human hunting behavior? Could foxes be used as an indicator of Palaeolithic occupation intensity and human impact on the Late Pleistocene environment? 
To answer these questions, I focused on the cave sites of the central Swabian Jura (Ach- and Lonetal) and the Hegau Jura, located at the southwestern edge of the Swabian Jura. To discuss my first question, I used 26 published zooarchaeological reports from twelve sites in the Ach- and Lonetal and re-examined the abundance of foxes over time using Bayesian statistics. I found out that foxes were more abundant in the archaeological record from the Aurignacian period onwards and that this was due to hunting activities by modern humans. Traps were likely used for hunting foxes, some of them baited with food leftovers and set at game passes in the vicinity of the inhabited caves. In contrast, foxes from the Middle Palaeolithic layers entered the caves naturally. To answer my second question, I used the analysis of stable carbon and nitrogen isotopes from the collagen of archaeological fox bones and reconstructed both the diet and the trophic niches. Thereby I could prove three basic feeding behaviors, one of them was influenced by humans. Some foxes from the Upper Palaeolithic showed synanthropic behavior, i.e. an adaptation to humans and their food resources, and this already about 30,000 years before the Neolithic. To address my last question, I used the knowledge gained from the previous two questions. This allowed me to establish a positive correlation between the abundance of foxes and the intensity of human settlement, as well as the occurrence of synanthropic foxes with the human population density and the hunting pressure on the megafauna in that region. Foxes can thus be used as a proxy for human activities and population density. The opportunistic foxes reacted to the environment influenced by human behavior by adapting their feeding strategies already in the early Palaeolithic periods.

Christoph Wissing (2016)

Multi-isotopic tracking (delta 13 C, delta 15 N, delta 34 S) of ancient trophic webs around the time of Neandertal replacement by anatomically modern humans in North-Western Europe

The study investigated ecological aspects of the mammoth steppe ecosystem in NW Europe with a special focus on the role of late Neandertals and early modern humans through the analysis of stable isotopes in bone collagen (delta 13C, delta 15N and delta 34S). Around the time of Neandertal extinction and the arrival of modern humans a diverse community of large herbivorous and carnivorous mammal lived under cold, fluctuating environmental conditions in NW Europe. The study reconstructed the ecological robustness of this ancient ecosystem and its response to oscillating climatic conditions as well as in regard of the ecological participation of Neandertals and early modern humans. The trophic web, the niche partitioning, the ecological flexibility of single species, as well as the general buffer capacity of this biocenosis are objects of investigation. The Belgium site Troisième caverne of Goyet provided a broad set of directly dated late Neandertal and very early modern human skeletal remains associated with a considerably assemblage of Pleistocene faunal remains. The occurrence of late Neandertals and early modern human skeletal remains at the same place are unique circumstance and allowed a direct comparison of several ecological aspects during a time span with a special relevance for the human evolution. The site Ziegeleigrube Coenen is contemporaneous with the occurrence of late Neandertals and reflects the ecosystem during or shortly after a cold spell. Even during such phases the structure of the mammoth steppe ecosystem was intact and provided consequently an adequate basis for late Neandertal subsidence. In an ecological context the Neandertals were part of there are no indications for any stress on the structure of the ecosystem. Through the analysis ofdelta delta 13C and delta 15N isotopic ratios in bone collagen of faunal and hominid remains the trophic web was evaluated. Processing of the isotopic data 2 through several statistical approaches allowed a detailed reconstruction of ecological niche partitioning of late Neandertals and early modern humans. Both hominid species occupied the same distinct ecological niche in terms of diet with a clear preference for mammoth and reindeer. The investigation of the delta 34S composition in Pleistocene bone collagen is a relatively novel approach and provided insights into spatial hominid procurement. The Goyet Neandertals do not reflect the local fauna delta 34S congruously their main prey had an origin different from the neighborhood of the Belgium sites (Scladina, Spy and Goyet). In contrast the delta 34S signal of the Spy Neandertals and the Goyet ancient modern humans corresponds to the values obtained on the local fauna. Potentially different mobility strategies among Pleistocene hominids while exploring the same prey species is the drafted scenario. The site Lommersum reflects the ecosystem at an initial phase of occupation by modern humans in the area, when Neandertals became already extinct. At this time the regional mammoth population was declining, since the horses entered their niche in distinct region of Western Europe. This study hypothesized that increasing hunting pressure on mammoth by modern humans was the main reason for this, since so far no significant environmental changes on terrestrial ecosystems could be observed in NW Europe. This study indicates that no distinct ecological change happened through the time of the last Neandertals, even during colder phases of the OIS 3. Potential ecological reasons could not be served as arguments for Neandertal extinction in NW Europe. With the capture of the area by representants of the Aurignacian the mammoth steppe ecosystem started to show evidences for stress, in this case at least partly independently of environmental fluctuations.

 

Márton Rabi (2014)

New Insights into the Origin and Phylogeny of Cryptodiran Turtles Based on Key Fossil Taxa from the Mesozoic of Asia

Most turtles from the Jurassic to Early Cretaceous of Asia are referred to the poorly circumscribed taxa Xinjiangchelyidae, Sinemydidae, and Macrobaenidae, groups that mostly include shell-based, generalized, small to mid-sized aquatic forms that are widely considered to represent the stem lineage of Cryptodira. These groups are critical for reconstructing the plesiomorphic anatomy of crown-cryptodires, the most diverse group of living turtles, and they are therefore particularly relevant for understanding the origin and early divergence of the primary clades of extant turtles. The complete description of excellent xinjiangchelyid and sinemydid material from the Upper Jurassic of Mongolia and the Middle Jurassic and Early Cretaceous of China (referable to Annemys levensis, A. latiens, Xinjiangchelys wusu nov. sp. and Manchurochelys manchoukuoensis) provides new insights into the anatomy of these otherwise poorly known groups. The overall similarity of the shells of the two Annemys species combined with significant differences in the skull indicate that these turtles probably partitioned the aquatic niche by exploring different feeding strategies. Among xinjiangchelyids, at least three different skull morphotypes can be differentiated, which implies a moderate level of ecological diversification among Late Jurassic Asian turtles. Phylogenetic definitions of Xinjiangchelyidae, Sinemydidae, and Macrobaenidae are provided for nomenclatural clarity and precision. Phylogenetic analysis weakly supports the inclusion of Xinjiangchelys wusu n. sp., A. levensis, and A. latiens in a monophyletic polytomy with other xinjiangchelyids, including Xinjiangchelys junggarensis and X. radiplicatoides. However, the analysis supports the unorthodox, though tentative placement of xinjiangchelyids and sinemydids outside of crown-group Testudines. A particularly interesting new observation is that the skull of xinjiangchelyids retains such primitive features as a reduced interpterygoid vacuity and basipterygoid processes. The homology of the basipterygoid processes is confidently demonstrated based on a comprehensive review of the basicranial anatomy of Mesozoic turtles and a new nomenclatural system is introduced for the carotid canal system of turtles. The loss of the basipterygoid process and the bony enclosure of the carotid circulation system occurred a number of times independently during turtle evolution suggesting that the reinforcement of the basicranial region was essential for developing a rigid skull, thus paralleling the evolution of other amniote groups with massive skulls. A thorough revision of the phylogeny of Macrobaenidae, Sinemydidae, and  closely allied forms yielded two main competing hypotheses: in the first, these taxa  form a paraphyletic grade, whereas in the second they form a monophyletic clade.  The inclusion of problematic tree changing taxa, such as Panpleurodires (stem +  crown side-neck turtles) has a major influence on the phylogenetic relationships of  Sinemydidae and closely allied forms. Manchurochelys manchoukuoensis nests  within Sinemydidae together with Sinemys spp. and Dracochelys bicuspis in the  majority of the analyses.