First report of cestode infection in the crustacean Artemia persimilis from Southern Chilean Patagonia and its relation with the Neotropical aquatic birds

The brine shrimp Artemia Leach (Crustacea, Branchiopoda), a keystone species in extremely saline wetlands all over the world, offers an excellent model to study species interactions (parasitism) and to elucidate “hidden fauna” (avian endoparasites). The present study is the first report on the parasite infection of the South American species Artemia persimilis from the Southern Chilean Patagonia (50ºS-53ºS). Samples were collected in Los Cisnes and Amarga lagoons, the two most austral populations of this crustacean described to date, during two seasons (spring and autumn). A total of 98 larvae of cestodes of the family Hymenolepididae (Cestoda, Cyclophyllidea) were found and identified as belonging to the following taxa: Confluaria podicipina (adult parasitic in grebes), Flamingolepis sp. (a cestode parasite of flamingos), Fimbriarioides (?) sp. (adults of the species of this genus infect waterfowl and shorebirds) and Wardium sp. (definitive host unknown, most probably charadriiform birds). This is a new geographical record of C. podicipina and the undescribed species Fimbriarioides (?) sp. for the Neotropical Region, the latter being the most widely distributed species at both localities and seasons surveyed, and the only species recorded in autumn (April). Cestode community composition in the Los Cisnes population was characterised by dominance of Flamingolepis sp., representing more than 65% of the total cestode species recorded, whereas in the Amarga population the most abundant parasite (> 83%) was Fimbriarioides (?) sp. Significant seasonal variations were detected in Cisnes lagoon for Flamingolepis sp. and C. podicipina, with exclusive presence of them in spring (November). Besides providing novel information on cestodes infection in A. persimilis, this study provides new data on the life-cycle of cestodes of Neotropical aquatic birds such as South American flamingos and grebes. Our finding expands the knowledge on the biodiversity and population dynamics of extreme and unique environments from high latitudes (Patagonia), but makes evident the need of further taxonomical and ecological studies to better understanding the life cycle of avian helminth parasites in the Neotropics, and to elucidate the role of aquatic invertebrates in the parasite life cycle in hypersaline wetlands from the Americas.

First report of cestode infection in the crustacean Artemia persimilis from Southern Chilean Patagonia and its relation with the Neotropical aquatic birds

The brine shrimp Artemia Leach (Crustacea, Branchiopoda), a keystone species in extremely saline wetlands all over the world, offers an excellent model to study species interactions (parasitism) and to elucidate “hidden fauna” (avian endoparasites). The present study is the first report on the parasite infection of the South American species Artemia persimilis from the Southern Chilean Patagonia (50ºS-53ºS). Samples were collected in Los Cisnes and Amarga lagoons, the two most austral populations of this crustacean described to date, during two seasons (spring and autumn). A total of 98 larvae of cestodes of the family Hymenolepididae (Cestoda, Cyclophyllidea) were found and identified as belonging to the following taxa: Confluaria podicipina (adult parasitic in grebes), Flamingolepis sp. (a cestode parasite of flamingos), Fimbriarioides (?) sp. (adults of the species of this genus infect waterfowl and shorebirds) and Wardium sp. (definitive host unknown, most probably charadriiform birds). This is a new geographical record of C. podicipina and the undescribed species Fimbriarioides (?) sp. for the Neotropical Region, the latter being the most widely distributed species at both localities and seasons surveyed, and the only species recorded in autumn (April). Cestode community composition in the Los Cisnes population was characterised by dominance of Flamingolepis sp., representing more than 65% of the total cestode species recorded, whereas in the Amarga population the most abundant parasite (> 83%) was Fimbriarioides (?) sp. Significant seasonal variations were detected in Cisnes lagoon for Flamingolepis sp. and C. podicipina, with exclusive presence of them in spring (November). Besides providing novel information on cestodes infection in A. persimilis, this study provides new data on the life-cycle of cestodes of Neotropical aquatic birds such as South American flamingos and grebes. Our finding expands the knowledge on the biodiversity and population dynamics of extreme and unique environments from high latitudes (Patagonia), but makes evident the need of further taxonomical and ecological studies to better understanding the life cycle of avian helminth parasites in the Neotropics, and to elucidate the role of aquatic invertebrates in the parasite life cycle in hypersaline wetlands from the Americas.

Population dynamics of the brine shrimp Artemia persimilis Piccinelli & Prosdocimi, 1968 (Crustacea, Anostraca) in a hypersaline lake of the Central Pampa (Argentina)

The anostracan Artemia is one of the few organisms that can inhabit hypersaline lakes. In Argentina, this genus is represented by two species: the invasive A. franciscana Kellogg, 1906 and the autochthonous A. persimilis Piccinelli & Prosdocimi, 1968, the latter being the only one recorded in the province of La Pampa. Some of the biological aspects of A. persimilis are known based on laboratory studies, and data on its ecology in natural conditions are scarce. The aim of this work is to present information on the density, biomass, and population structure of A. persimilis in relation to environmental variables in Utracán, a hypersaline lake of the semiarid Central Pampa of Argentina. Water and zooplankton samples were taken monthly from May 2009 until August 2010. The mean density and biomass were 56.98 ind.L-1 (± 106.64) and 1.23 mg.L-1 (± 1.35), respectively. The species was negatively affected by salinity, and it was absent between November and February, when salinity exceeded 320 g.L-1. However, when it was present, even during the months of higher salinity, a high proportion of naupliar stages was found, which could indicate that, in nature, A. persimilis can reproduce with high salinity. Although it has been indicated that A. persimilis could be displaced by A. franciscana, the highest tolerance of the former at low temperatures, which allowed the population to continue reproducing at values close to 3°C, would limit its displacement. However, an increase in the temperature of lakes as a result of global warming could modify this situation and allow the advance of the introduced species to the south.

Species co-occurrences based on a presence/absence null model for Copepoda and cladocerans in Patagonia and Tierra del Fuego lakes and ponds

The zooplankton assemblages in southern Chilean Patagonia are characterized by calanoid dominance and low species number that is observable under oligotrophic status and wide conductivity values, whereas at mesotrophic status the daphnids are dominant with high species number, and finally at hyper-saline environments halophilic species such as Artemia persimilis and/or the calanoid Boeckella poopensis predominate. In the present study data of different lakes and ponds between 45-53° S were analyzed, with the aim to determine potential structures at different sites. For this purpose a null model based in guild structure was applied, considering each guild a different kind of water body (lake, small lake, permanent pond, ephemeral pond, and saline lake). The results revealed in two simulations that guild are structured. These results are similar with other descriptions on the basis of null models that revealed a random pattern of species associations for similar ecosystems due to many species repeated in all or practically all studied sites or similarities of ecological features. Ecological and biogeographical topics were discussed.