Tibetan Artemia (Crustacea: Anostraca) mitogenomic biodiversity and population demographics

Abstract Hypersaline lakes in arid and semi-arid areas are unique ecosystems that harbour unique extremophile organisms such as Artemia, the paradigmatic example of adaptation to harsh living conditions. We assessed the mitogenomic biodiversity of Artemia species from the Tibetan Plateau, China, a remote and yet minimally disturbed ecosystem with a variety of hypersaline lakes. Analysis of ten Tibetan salt lakes demonstrated the occurrence of two regionally endemic species, Artemia tibetiana and Artemia sorgeloosi, with the latter being the dominant species with eight localities. Both species coexist in Jingyu and Jibu lakes, representing the first case of natural distribution overlap between sexual Artemia species. Artemia sorgeloosi exhibits higher genetic diversity and interpopulation differences, a result consistent with the heterogeneity of local salt lakes, local Artemia population demographics, and their adaptive potentials. Significant FST values demonstrate a gene flow barrier between A. sorgeloosi populations that is compatible with an ‘island biogeography’ distribution pattern, making the Tibetan Plateau a sort of natural laboratory to study intraspecific population differences. Artemia sorgeloosi and the exotic Artemia franciscana were found coexisting in Yangnapen Lake, demonstrating the ability of this invasive species to colonize high-altitude inland habitats, and the need to monitor its presence and eventual expansion.