Opera Lilloana 57 (2024): Diatomeas de Humedales Altoandinos de Catamarca y Jujuy, Argentina

The western border of Argentina is delimited by the Andes Mountain Range and, like other South American territories, it has large areas of high mountains (more than 2500 m asl) that are home to numerous wetlands. Mountain ecosystems have
gained importance as biological reserves for endemic species. In arid or semi-arid areas, these wetlands contribute to the settlement of microclimates, which maintain their local levels of humidity and precipitation through evaporation and evapotranspiration. In northwestern Argentina, parts of the Puna and Altos Andes ecoregions extend from the border with Bolivia to the north of Catamarca Province, reaching altitudes greater than 4500 m asl. In these ecoregions, there is a significant number of high-altitude wetlands, ranging from purely fresh to frankly hypersaline. Despite the high diversity of wetlands, little is known about the diatom populations living there. This contribution aims to integrate the information collected over 24
years of study (1998-2022) about the diversity of diatoms inhabiting these wetlands. We analyzed samples from 55 water bodies located in the Argentine provinces of Catamarca (32) and Jujuy (23). From a total of 375 species and varieties found
throughout our work, here we only present 223 taxa with their dimensions, and photographs taken by light microscopy and, in some cases, by scanning electron microscopy. From these taxa, 34 were new records for the country, two new combinations (Craticula cuspidata var. gracilis and Ulnaria ulna var. constricta), and five new species to science (Anomoeoneis punae, Pseudostaurosira ferrarioae, Staurophora vilamaensis, Staurosirella galanensis, and Staurosirella salitrensis). In this paper we describe a new species named Surirella andeana and we propose a new combination, the Planothidium chilense var. subaequalis.