The aim of this paper is to expand the current knowledge on the distribution, ecology and morphology of Pseudostaurosira cataractarum (Hustedt) C.E. Wetzel, E. Morales et Ector. We analysed several freshwater diatom assemblages within the Palearctic (Czech Republic, Europe) and Neotropic ecozones (Argentina and Bolivia, South America). In all localities, small araphids were the dominant or co-dominant group. Inside this group, P. cataractarum was only dominant in the samples from Argentina and Czech Republic, while the Bolivian samples had only a few individuals. RDA and PCA analyses show that the relative abundance of P. cataractarum was positively correlated with water conductivity. The following measurements resulted from the morphometric analysis, apical axis: 2.8-8.2 lm, transapical axis: 2.7-7.2 lm and stria density: 15-29 in 10 lm. In conclusion, the present is the first report of P. cataractarum for continental Europe (from fossil material) and the Neotropic ecozone (from extant populations). Besides having a preference for subaerial habitats, this taxon could be locally conditioned by water conductivity, although in each of the analysed samples this species was associated with cosmopolitan diatoms that are tolerant to a wide range of environmental conditions. Based on the morphometric analyses in studied populations, we propose that the size range for the apical and transapical axes of P. cataractarum should be expanded at the lower end of the range. Likewise, the range of stria density should be expanded since it is wider than that presented for the type population from Indonesia (Java). Consequently, an emended description is presented based on our study and on published data on type and fossil populations.

Las investigaciones arqueológicas y paleoambientales han demostrado que la mayoría de las ocupaciones humanas en Antofagasta de la Sierra (Puna sur de Argentina) se han establecido en relación estrecha con el agua, ya que su presencia es necesaria para el consumo (humano y animal), el riego, el forraje y la caza. Es por

Two new araphid diatom (Bacillariophyta) species, Pseudostaurosira oliveraiana sp. nov. and Staurosira catamarcensis sp. nov. are described from fossil material taken from the saline Laguna Colorada (Argentinian Altiplano). The morphology of the new species is studied using both light (LM) and scanning electron microscopy (SEM) and is compared to that of similar taxa. Pseudostaurosira oliveraiana sp. nov. is different from other species of Pseudostaurosira by its linear to lanceolate valve outline, with apices usually subcapitate and cuneate. Staurosira catamarcensis sp. nov. is unique because it has short striae that are restricted to the valve margins, delimiting a wide and lanceolate sternum, which resembles some species of Pseudostaurosira. Also, it is the first species described in Staurosira lacking apical pore fields, expanding the high morphological variation that already exists within this genus. Additionally, two new combinations are proposed: Pseudostaurosira santaremensis comb. nov. and Staurosirella canariensis comb. nov. based on information at the SEM and LM level presented in the literature.

En este trabajo se presentan nuevas evidencias sobre las tecnologías paleohidráulicas de la red de riego de Miriguaca 1 (MS1) localizada en Antofagasta de la Sierra (Catamarca). Estas evidencias permiten profundizar sobre las interpretaciones del funcionamiento y los diseños hidráulicos de las redes conocidas hasta el momento en la Puna meridional argentina. A través de análisis de imágenes satelitales y de controles pedestres se logró identificar una gran cantidad de campos de cultivo y canales e incluso sus modificaciones. También se detectó el uso de una represa de riego, la cual constituye la primera evidencia de esta naturaleza para la Puna meridional. Este dispositivo hídrico habría permitido la acumulación de agua para una mayor extensión de riego y un control sobre el tiempo para el uso del agua. En base al material arqueológico vinculado a la red de riego y su diseño se discute la cronología de su construcción y sus modos de uso.