Dinosaur Fossils Predict Body Temperatures

Perhaps the greatest mystery surrounding dinosaurs concerns whether they were endotherms, ectotherms, or some unique intermediate form. Here we present a model that yields estimates of dinosaur body temperature based on ontogenetic growth trajectories obtained from fossil bones. The model predicts that dinosaur body temperatures increased with body mass from approximately 25 °C at 12 kg to approximately 41 °C at 13,000 kg. The model also successfully predicts observed increases in body temperature with body mass for extant crocodiles. These results provide direct evidence that dinosaurs were reptiles that exhibited inertial homeothermy

Using traditional biometrical data to distinguish West Palearctic wild boar and domestic pigs in the archaeological record : new methods and standards

Peer reviewedPostprin

Nuevas drogas de abuso. Las catinonas sintéticas (“sales de baño”)

Existen en la actualidad una amplia gama de drogas, que generalmente son sustancias ilegales usadas por sus propiedades recreativas, creadas a partir de otras drogas ya conocidas anteriormente y que, usando diversas estrategias a la hora de su comercialización, se han puesto en circulación evadiendo controles y convirtiéndose en ``legales´´. Sustancias como las catinonas sintéticas, los cannabinoides sintéticos, krokodil se comercializan sin restricción debido a vacíos legales. Las catinonas sintéticas son el grupo más común de compuestos psicoactivos, derivados la planta Catha edulis que se comercializan como “sales de baño” tanto en tiendas como a través de internet. Su acción se basa en dos mecanismos implicados: Bloqueo de la recaptación del transportador y elevación de la liberación presináptica provocando síntomas excitatorios tales como: agitación psicomotora, automatismos, parkinsonismo, temblores, taquicardia, dolor torácico, cambios en el segmento S-T, hipertensión, hipertermia, midriasis, psicosis paranoide, depresión, ataques de pánico, entre otros. Presenta varios patrones de consumo principalmente de forma esnifada. Su tratamiento es parecido al de la intoxicación por MDMA, mediante el uso de benzodiacepinas y tratamientos de soporte

La place des restes humains au sein de l’étude des sépultures préhistoriques : approche épistémologique et historique du XIXe siècle à nos jours

L’archéologie de la mort s’intéresse à la gestion des morts et de la mort par les populations du passé. Pour les temps reculés de la Préhistoire, les principaux vestiges de cadavres à disposition sont les ossements. Cependant, l’histoire de la discipline révèle que ces restes osseux n’ont pas toujours constitué les principaux objets scientifiques sur lesquels les archéologues et préhistoriens ont construit leurs interprétations des sépultures préhistoriques. Ils s’appuyaient essentiellement ..

Can Dental Microwear Textures Record Inter-Individual Dietary Variations?

International audienceBackground: Dental microwear analyses are commonly used to deduce the diet of extinct mammals. Conventional methods rely on the user identifying features within a 2D image. However, recent interdisciplinary research has lead to the development of an advanced methodology that is free of observer error, based on the automated quantification of 3D surfaces by combining confocal microscopy with scale-sensitive fractal analysis. This method has already proved to be very efficient in detecting dietary differences between species. Focusing on a finer, intra-specific scale of analysis, the aim of this study is to test this method's ability to track such differences between individuals from a single population. Methodology/Principal Findings: For the purposes of this study, the 3D molar microwear of 78 individuals from a well-known population of extant roe deer (Capreolus caprelous) is quantified. Multivariate statistical analyses indicate significant seasonal and sexual differences in individual dental microwear design. These are probably the consequence of seasonal variations in fruit, seed and leaf availability, as well as differences in feeding preference between males and females due to distinct energy requirements during periods of rutting, gestation or giving birth. Nevertheless, further investigations using two-block Partial Least-Squares analysis show no strong relationship between individual stomach contents and microwear texture. This is an expected result, assuming that stomach contents are composed of food items ingested during the last few hours whereas dental microwear texture records the physical properties of items eaten over periods of days or weeks. Conclusions/Significance: Microwear 3D scale-sensitive fractal analysis does detect differences in diet ranging from the inter-feeding styles scale to the intra-population between-season and between-sex scales. It is therefore a possible tool, to be used with caution, in the further exploration of the feeding biology and ecology of extinct mammals

Carbon and oxygen isotope variability among foraminifera and ostracod carbonated shells

This study investigates the effect of biological and environmental inter-individual variability on the meaning of d18O and d13C values acquired on small carbonated shells. First we present data obtained with a MultiPrep automated carbonate system on small sample sizes of a homogeneous carbonate material: Carrara marble. This demonstrates the capacities of the analytical system to reliably run small amounts of carbonates even down to 10 mg. Then we present two data sets obtained on real fossil samples of various size (sensu number of individual organisms) calibrated against the NBS19 carbonate standard. Both datasets evidence a clear trend of between-biological sample standard deviation increase for both d18O and d13C measurements when the number of pooled specimens per sample decreases. According to the results obtained from a systematic study of a geologically homogeneous sample of coeval fossil Elphidium foraminifera, we estimate that there is 95% of chances to reach between-biological sample standard deviation values higher than 1.02‰ (d18O) and 1.45‰ d13C) based on single-cell measurements. Such values are one order of magnitude higher than the instrumental standard deviations associated with these stable isotope ratios. Conversely, a minimum of 35 (d18O) and 44 (d13C) pooled specimens of Elphidium appears necessary to reach a between-sample standard deviation £ 0.25‰ with a probability of 95%. Such biological intrinsic and irreducible variability between coeval individuals, and thus samples, clearly questions the interest for single-cell analyses, more precisely, for coastal marine species, such as Elphidium, subject to many environmental changes during their life-time. Indeed, strong variations in salinity or temperature, as well as biogenic fractionation, could influence the isotopic composition of an individual specimen. Results might be less problematic for an average community including several tests. This paper underlines uncertainties linked to specific environments in which selected organisms live, especially for paleoceanographic or paleoclimatic reconstruction purposes where secular oxygen and carbon isotope variations typically range from 0.5 to 1.5‰

Sallèles-Cabardès – Grotte Gazel

Date de l'opération : 1992 - 1997 (RE) ; 1992 - 1997 (FP) Inventeur(s) : Sacchi Dominique (CNRS) La grotte Gazel, implantée entre plaine et montagne, renferme le site magdalénien le plus vaste et le plus documenté du Midi méditerranéen. Il se compose d'une aire d'habitat qui recouvrait initialement une étendue supérieure à 1 000 m2, et, en marge de celle-ci, d'une galerie ornée de gravures pariétales. L'aire d'habitat La salle centrale de la galerie supérieure, le secteur le mieux préservé, r..

An ailuravine rodent from the lower Eocene Cambay Formation at Vastan, Western India, and its palaeobiogeographic implications

A new ailuravine rodent, Meldimys musak sp. nov. (Mammalia: Rodentia, Ischyromyidae), is recorded from the lower Eocene lignites of western India. It is the oldest record of Rodentia from India. M. musak is more derived than the earliest Eocene ailuravine Euromys cardosoi from Portugal and more generalized than late early Eocene E. inexpectatus and Ailuravus michauxi from France. Its dental morphology closely corresponds to the middle early Eocene species M. louisi, which lived about 52 Ma in Western Europe. Meldimys was previously known only from Europe, and ailuravines were previously reported only from Europe and North America. Its occurrence in India allows the first direct correlation between the early Eocene land mammal horizons of Europe and India, and raises the possibility of a terrestrial faunal exchange between India and Eurasia close to the Palaeocene-Eocene transition

Worldwide Genotyping in the Planktonic Foraminifer Globoconella inflata: Implications for Life History and Paleoceanography

The planktonic foraminiferal morpho-species Globoconella inflata is widely used as a stratigraphic and paleoceanographic index. While G. inflata was until now regarded as a single species, we show that it rather constitutes a complex of two pseudo-cryptic species. Our study is based on SSU and ITS rDNA sequence analyses and genotyping of 497 individuals collected at 49 oceanic stations covering the worldwide range of the morpho-species. Phylogenetic analyses unveil the presence of two divergent genotypes. Type I inhabits transitional and subtropical waters of both hemispheres, while Type II is restricted to the Antarctic subpolar waters. The two genetic species exhibit a strictly allopatric distribution on each side of the Antarctic Subpolar Front. On the other hand, sediment data show that G. inflata was restricted to transitional and subtropical environments since the early Pliocene, and expanded its geographic range to southern subpolar waters ∼700 kyrs ago, during marine isotopic stage 17. This datum may correspond to a peripatric speciation event that led to the partition of an ancestral genotype into two distinct evolutionary units. Biometric measurements performed on individual G. inflata from plankton tows north and south of the Antarctic Subpolar Front indicate that Types I and II display slight but significant differences in shell morphology. These morphological differences may allow recognition of the G. inflata pseudo-cryptic species back into the fossil record, which in turn may contribute to monitor past movements of the Antarctic Subpolar Front during the middle and late Pleistocene