Abstract

The brine shrimp genus Artemia Leach (Crustacea, Branchiopoda), a keystone group in hipersaline wetlands all over the world, offers an excellent model to study species interactions (parasitism) and to explore "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 (50 degrees S-53 degrees S). 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 genus Fimbriarioides 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 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 Los 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) and makes evident the need of further taxonomical and ecological studies for better understanding the life cycles of avian helminth parasites in the Neotropics and the role of aquatic invertebrates in them.