Who Killed the Small Mammals of Ittenheim (Northeastern France)?:an integrative approach and new taphonomic data for investigating bone assemblages accumulated by small carnivores

Abstract Small carnivores are susceptible to regularly accumulating small- to medium-sized mammal remains in both natural and archaeological sites. However, compared to nocturnal birds of prey, these accumulations are still poorly documented and are generally based on a limited number of samples, including those of relatively small size. Here, we present an analysis of European hamster remains from a rescue excavation at Ittenheim (Bas-Rhin, Grand-Est, France), which were recovered from an infilled burrow, three meters below the current surface. The remains are well preserved and exhibit large proportions of tooth marks. Comparisons with a new and existing reference collection combined with an analysis of all recovered faunal remains suggest the accumulation reflects the action of young red foxes. This is supported by the fact that, although these young individuals leave teeth mark, they do not necessarily consume all parts of medium-sized prey species, including the European hamster. Conversely, the remains of smaller rodents, such as microtine, show distinct patterns of digestion and tooth marks. Carnivore bone accumulations from scats are generally poorly preserved; however, our results demonstrate prey size plays a major role, both qualitatively and quantitatively, in skeletal representation, bone preservation, and bone surface modifications. The present paper underlines the need for more diversified taphonomic reference collections based on an integrative approach designed to evaluate multi-taxa accumulations

Incisor microwear of Arctic rodents as a proxy for microhabitat preference.

International audienceChanging environmental conditions in the Arctic make it important to document and understand habitat preferences and flexibility of vulnerable high-latitude mammals. Indirect proxies are especially useful for elusive species, such as rodents. This study explores incisor microwear as an indicator of variation in behavior and microhabitat use in Siberian lemmings (Lemmus sibiricus) and narrow-headed voles (Lasiopodomys gregalis) from the Yamal Peninsula, Russia. Fifty-nine individuals were sampled at four sites along a latitudinal gradient from forest-tundra ecotone to high-Arctic tundra. Lemmings are present at the northernmost site, voles at the southernmost site, and both species at the middle two. Lemmus sibiricus prefers wet, mossy lowland, whereas La. gregalis favors drier thickets and more open microhabitats and burrows underground. Feature-based analyses indicate higher densities of features and more uniformly oriented striations for voles than lemmings at sites with both species. The species also differ significantly in microwear texture attributes suggesting larger features for lemmings, and smaller ones, but more of them, for voles. While no texture differences were found between sites within species, voles from sites with open tundra have higher striation densities than those from the forest-tundra ecotone. Furthermore, lemmings from open tundra sites have higher striation densities than those from the water-saturated, moss-covered northernmost site. While microhabitat preferences and burrowing by voles likely contribute to differences between species, variation within seems to reflect habitat variation given differences in abrasive loads between sites. This suggests that incisor microwear patterning can be used to track microhabitat differences among Arctic rodent populations

SWIFTS : Micro-spectromètre optique à ondes guidées contra-propagatives

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New insights in Neanderthal palaeoecology using stable oxygen isotopes preserved in small mammals as palaeoclimatic tracers in Teixoneres Cave (Moià, northeastern Iberia).

25 pagesInternational audienceThe northeastern region of Iberia constitutes a natural pass-area for arriving populations into the peninsula and becomes a key area to understand Neanderthal resilience to changing environmental conditions experienced during Marine Isotope Stage 3 (MIS 3; 60–30 ka). Short-term but repeated occupations by Neanderthal groups occurred in Teixoneres Cave (Moià, Barcelona) in alternation with large and small carnivores during MIS3. Abundant small-mammal remains accumulated in units III and II of this fossiliferous deposit, providing local climatic and environmental information. This work focuses on the taphonomic history of small-mammal faunas, which a is clue to validate previous palaeoecological interpretations. As was observed with leporids and bird remains, raptors are considered the major source of small-mammal remains. The most likely accumulator is an opportunistic predator, the eagle owl, with very rare inputs by mammalian carnivores. In parallel, high-resolution palaeoclimatic data are provided through oxygen isotope analyses (δ 18 O) of rodent teeth from four subunits (IIIb to IIa), which are compared with independent methods of palaeotemperature estimations. According to air temperatures estimated from δ 18 O rodent teeth, cooler conditions than present day (− 1.6/ − 0.5 °C) are recorded along the sequence, but homogenous (< 1 °C). Complementary methods also explain higher rainfall than present day (+ 44/ + 682 mm). Only slight changes between units III and II show climatic instability, which could be related to palimpsests of stadial-interstadial events. Climatic stable conditions are reported from coeval isotopic and palaeodiet analyses from northeastern Iberia in agreement with the palynological records that underline how the Mediterranean area could have sustained rich ecosystems that assured the Neanderthal subsistence during the abrupt climatic pulsations of the Late Glacial

Real-space observation of spectral degeneracy breaking in a waveguide-coupled disk microresonator

International audienceWe report on the real-space observation of resonant frequency splitting in a high-Q waveguide-coupled silicon-on-insulator microdisk resonator. Phase sensitive near-field analysis reveals the stationary nature of the two resonant states, and spectral investigations clearly show their orthogonality. These measurements emphasize the role of the coupling waveguide in this splitting phenomenon. The symmetry of the two stationary whispering gallery modes is clearly observed and is found to follow the axial symmetry of the waveguide-coupled microdisk as it has been reported by earlier theoretical predictions

New bioclimatic models for the quaternary palaearctic based on insectivore and rodent communities

Mammal remains, preserved in archaeological and palaeontological deposits, are commonly used to reconstruct past terrestrial climates and environments. Here we propose new species-specific models for Bioclimatic Analysis, a palaeoclimatic method based on a climatic restriction index for each mammal species, discriminant analysis, and multiple linear regressions. Our new models are based on small mammal associations, particularly insectivores and rodents, from Quaternary paleoarctic contexts. A dataset including new localities and an updated taxonomy was constructed in order to develop two approaches, the first using only Rodentia, the second based on associations including both Rodentia and Eulipotyphla. Both approaches proved to be reliable for inferring both climate zone and quantifying temperature, precipitation, and seasonality. Rarefaction analysis revealed these new models to be reliable even when a substantial percentage of species from the original palaeocommunity was absent from the fossil site. Application of these new models to small mammal associations from two sequences (Balma de l'Abeurador, France and El Mirón, Spain) spanning from the Last Glacial Maximum to the Holocene are consistent with the primary climatic changes recorded by regional Pyrenean proxies and showed an increase in mean annual temperature of between 3 and 5 °C