A NEW SPECIES OF TAPINURUS FROM THE CAATINGA OF PIAUI, NORTHEASTERN BRAZIL (SQUAMATA, TROPIDURIDAE)

Tapinurus helenae sp. nov. is described from northeastern Brazil. The species is characterized by a dorsoventrally depressed body three bluish-white longitudinal stripes, the middorsal one interrupted at the scapular area, and an ochre colored dorsum that is lacking in larger males. Tapinurus helenae is easily distinguished from the other two known species, T. semitaeniatus and T. pinima, by its interrupted middorsal stripe. The new species inhabits calcareous massifs and sandstones in forested caatinga at the Toca de Cima dos Pilao, Sao Raimundo Nonato, Piaui, northeastern Brazil.46446246

Description of the hemipenial morphology of Tupinambis quadrilineatus Manzani and Abe, 1997 (Squamata, Teiidae) and new records from Piaui, Brazil

Few data are available on the morphology of the hemipenis of teiid lizards, especially those of the recently-defined genus Tupinambis, a widely-distributed group of large-bodied lizards. This study provides an illustrated description of the hemipenis of Tupinambis quadrilineatus, which is similar to that of other representatives of the Tupinambinae subfamily. New records of the species from the state of Piaui, in northeastern Brazil, are also presented.361617

Granular materials: micromechanical approaches of model systems

International audienceAn overview is given of micromechanical approaches to the rheology of granular materials, from solidlike granular packs to large plastic strains and dense inertial flows, which essentially relies on the numerical simulation (by the "discrete element method" or DEM) of simple model systems. The main features of contact laws are presented, and then it is insisted on the importance of the geometry of disordered granular assemblies, such that some details of contact interactions are in fact often irrelevant. Some salient results, as obtained from DEM studies over the last decades, are presented about the variety of microstructures and internal states, depending on assembling processes; on elasticity and its (limited) role in quasistatic granular behavior; on plastic strains and the fon-damental concept of critical states, and on its recent applications to the rheology of dense granular flows and suspensions