Oribatid mites (Acari: Oribatida) from the Patagonian steppe, Argentina.

Knowledge of the oribatid mite community from Patagonian steppe is scarce compared with other environments, such as the Andean-Patagonian forest. In the present research we identified oribatid mites under different environmental conditions: two Patagonian steppe types (grass and shrub), two soil characteristics (bare and covered soil) and two different seasons (autumn and spring). A total of 42 species/morphospecies were found, 13 were new records for Chubut and one was a new record for Argentina. In view of its ecological role in soil formation, it is fundamental that knowledge about this fauna is enhanced in order to provide baselines for study and to aid further understanding about its ecology.

Track analysis of Oribatid mites (Acari: Oribatida) of the Subantarctic subregion of South America.

We analysed distributional data of 30 species of Oribatid mites of the Subantarctic subregion of southern South America in order to contribute to elucidate their biotic evolution. We constructed individual tracks for the species analysed, based on published and unpublished records. After superposing them we obtained six generalized tracks and five nodes. Four generalized tracks (T2, T3, T4 and T6) extend along and near the Andean ranges, whereas two generalized tracks (T1 and T5) may be artefacts caused by the lack of information. The generalized tracks and nodes show the complex relationships of the austral biota, as hypothesized in previous contributions based on other plant and animal taxa.