Constructing, Bootstrapping and Comparing Morphometrical and Phylogenetical Trees: a Case Study of New World Monkeys (Platyrrhini, Primates

International audienc

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

Multi-method approach using small vertebrate assemblages to reconstruct the Marine Isotope Stage 6 climate and environment of the Lazaret cave sequence (Maritime Alps, Nice, France)

Marine Isotope Stage 6 (MIS 6; ca. 185–135 ka) is the penultimate glacial stage and constitutes the end of the Middle Pleistocene. This glacial period is typified by generally cold and dry conditions in the western Mediterranean region. Despite the relatively large number of pollen and speleothem studies of MIS 6 in this region, the number of MIS 6 archaeological sites is low. Lazaret cave, situated at 26 m a.s.l. in the city of Nice in southern France, contains an archaeological sequence (layers CII inf. to CIII) dated to MIS 6. We present a multi-method approach using the small-vertebrate assemblages (mainly rodents and herpetofauna) from the entire sequence to characterize the climate and the environment of the site. The Mutual Ecogeographic Range, the Bioclimatic Model andthe Quantified Ecology methods, as well as the Taxonomic Habitat Index, Climatograms and the Simpson Diversity Index were used to reconstruct the palaeoenvironmental and palaeoclimatic conditions. The results suggest a generally cold climate with a relatively humid environment and a landscape dominated by deciduous temperate forests. The findings are consistent with the general trends reported from other proxies (large mammals, birds and marine gastropods) studied at Lazaret cave, other MIS 6 sites in the Mediterranean region with small vertebrate studies and the general trends shown by marine cores, terrestrial pollen sequences and speleothems from western Europe. Given the scarcity of data for MIS 6 archaeological sites, Lazaret cave constitutes an important site for our knowledge of the climate and the environment of this period

Karyological and dental identification of Microtus limnophilus in a large focus of alveolar echinococcosis (Gansu, China).

International audienceA study of voles (Arvicolidae, Rodentia) from Gansu (China) designed to identify a potential host of Echinococcus multilocularis, responsible for human alveolar echinococcosis, leads to a general analysis of Microtus limnophilus population karyotypes, M1 of M. oeconomus populations from all of Eurasia and of M. limnophilus of Mongolia. The Microtus of Gansu belonging to the nominal subspecies M. limnophilus limnophilus (2n = 38; NF = 58) differs markedly in size and shape of M1 from the M. limnophilus of Mongolia, which must therefore be considered as a new subspecies M. limnophilus of malygini nov. ssp. (2n = 38; NF = 60) and the M. oeconomus of Mongolia should be ranked as M. oeconomus kharanurensis nov. ssp. (2n = 30; NF = 60)

RESEARCH ARTICLE Body-size structure of Central Iberian mammal fauna reveals semidesertic conditions during the middle Miocene Global Cooling Event

We developed new quantitative palaeoclimatic inference models based on the body-size structure of mammal faunas from the Old World tropics and applied them to the Somosaguas fossil site (middle Miocene, central Iberian Peninsula). Twenty-six mammal species have been described at this site, including proboscideans, ungulates, carnivores, insectivores, lagomorphs and rodents. Our analyses were based on multivariate and bivariate regression models correlating climatic data and body-size structure of 63 modern mammal assemblages from Sub-Saharan Africa and the Indian subcontinent. The results showed an average temperature of the coldest month higher than 26ÊC for the Somosaguas fossil site, a mean annual thermal amplitude around 10ÊC, a drought length of 10 months, and an annual total precipitation greater than 200 mm per year, which are climate conditions typical of an ecotonal zone between the savanna and desert biomes. These results are congruent with the aridity peaks described over the middle Aragonian of Spain and particularly in the local biozone E, which includes Somosaguas. The aridity increase detected in this biozone is associated with the Middle Miocene Global Cooling Event. The environment of Somosaguas around 14 Ma was similar to the current environment in the Sahel region of North Africa, the Horn of Africa, the boundary area between the Kalahari and the Namib in Southern Africa, south-central Arabia, or eastern Pakistan and northwestern India. The distribution of modern vegetation in these regions follows a complex mosaic of plant communities, dominated by scattered xerophilous shrublands, semidesert grasslands, and vegetation linked to seasonal watercourses and ponds.Peer reviewe