Zethus wileyi Stange sp. nov. (Panama) is described and a cladistic analysis is carried in order to determine the relationship between the new species and the other species in the hilarianus species-group. The new species ...

The knowledge of the distributional patterns of saproxylic beetles is essential for conservation biology due to the relevance of this fauna in the maintenance of ecological processes and the endangerment of species. The ...

The relative effects of host species identity, locality and season on ectoparasite assemblages (relative abundances and species richness) harboured by four cricetid rodent hosts (Akodon azarae, Oligoryzomys flavescens, ...

Based on analysis of more than fifty species of neotropical grasshoppers with a neo XY sex determining mechanism, the authors suggest that species acquiring such mechanisms are finally extinct at the end of a relatively ...

Cyperaceae possesses both non-Kranz and Kranz species, with four subtypes that differ in the number and continuity of the bundle sheaths and by presence of chloroplasts. The ontogeny of the bundle sheaths of leaves and ...

Genetic analyses of sex determination have identified sex chromosomes in many teleost fish species. However, there are several cases for which sex ratios do not fit perfectly with the expectations of heterogametic systems, ...

Natural environments have been worldwide affected by the growing impact of anthropogenic actions that promote the reduction or the extinction of several vertebrate species. Aquatic ecosystems represent one of the most ...