Cytogenetic analysis of four argentinean populations of Artemia (Crustacea Branchipoda: Anostraca)

Artemia brine shrimps inhabit hypersaline ecosystems all over the world except Antarctica. In South America two bisexual diploid species are encountered: Artemia franciscana Kellogg distributed along America and Artemia persimilis Piccinelli and Prosdocimi restricted to Argentina and a few Chilean localities. A. franciscana was recently cited for the first time in our country and our results suggested a possible hybridization in Las Tunas Lagoon (Córdoba province) between both species. In the present work four new Argentinean populations of Artemia have been cytogenetically analyzed by conventional staining, silver staining, and C and DAPI banding. The populations Salina La Antigua (La Rioja province), Salinas Grandes (Córdoba province) and Pampa de las Salinas (San Luis province) gave similar results compatible with A. franciscana (2n=42, n=21). Conversely, Salitral de la Vidriera population (Buenos Aires province) would correspond to A. persimilis (2n=44). While in Salitral de la Vidriera only one or two small chromocenters C positive and DAPI bright were detected, in Pampa de las Salinas and Salinas Grandes many of them were observed. Nevertheless, both populations presented less heterochromatin than the Artemia franciscana reference strain from Great Salt Lake (USA). These results constitute further evidence to the occurrence of heterochromatin variations not only between both species but also within each one. Last but not least, with the present contribution A. franciscana is now cited in three new Argentinean localities.