A new species of Archaebranchinecta (Anostraca: Branchinectidae) from the South American Altiplano.

A detailed morphological comparison was carried out among specimens of several samples of Archaebranchinecta Rogers Coronel, 2011 from the Altiplano of Peru, Bolivia, and Argentina. Surprisingly, striking differences were found between Peruvian samples collected near the western shore of Lake Titicaca, and those from Bolivia taken southwardly, near the east coasts of River Desaguadero and Lake Poopó. Accordingly, the new species Archaebranchinecta aimara sp.

The Hyalella (Crustacea: Amphipoda) species cloud of the ancient Lake Titicaca originated from multiple colonizations.

Ancient lakes are renowned for their exceptional diversity of endemic species. As model systems for the study of sympatric speciation, it is necessary to understand whether a given hypothesized species flock is of monophyletic or polyphyletic origin. Here, we present the first molecular characterization of the Hyalella (Crustacea: Amphipoda) species complex of Lake Titicaca, using COI and 28S DNA sequences, including samples from the connected Small and Large Lakes that comprise Lake Titicaca as well as from a broader survey of southern South American sites.

Review of the Eulimnadia (Branchiopoda: Spinicaudata: Limnadiidae) from Argentina with the description of a new species.

A new spinicaudatan species, Eulimnadia pampa sp. nov., is described from Argentina mostly based on the differential egg morphology.

UV radiation as a potential driving force for zooplankton community structure in Patagonian lakes.

This article explores the potential role of UV radiation (UVR) as an influence on zooplankton communities. In the first section we provide a general overview of UVR effects on freshwater zooplankton, with an emphasis on Argentine and Chilean environments. In the second section we present the results of a survey involving 53 temperate lakes across a gradient of UVR exposure to determine patterns of species richness and specific diversity.

New insights into the distribution of polyploid Daphnia: the Holarctic revisited and Argentina explored.

It has long been known that polyploid organisms are more prevalent in arctic than in temperate environments. Past explanations for this geographical trend have focused on the role of glacial cycles in generating polyploids and the influence of abiotic factors in favouring polyploidy in the north. In combination, these mechanisms probably suffice to explain the observed geographical cline in ploidy levels in members of the Daphnia pulex complex in the Holarctic.

A field and laboratory study on factors affecting polymorphism in the rotifer Keratella tropica.

We present data on polymorphism of the rotifer Keratella tropica from an outdoor, mesoscale experiment and a series of laboratory induction assays. In the outdoor experiment the biomass of planktonic crustaceans was noticeably depressed by larval fish predation, and associated with this depression K. tropica underwent a striking reduction of caudal spines.