The taxonomic status of Artemia monica (Crustacea: Anostraca)

Species are fundamental units of nature that need proper identification in order to assess and conserve biodiversity. Artemia is a model crustacean for population analysis and comparison in regionally endemic sexual species and parthenogenetic lineages distributed in hypersaline lakes, lagoons, and solar saltworks scattered in arid and semi-arid areas worldwide. The taxonomy of two American Artemia species has been controversial: Artemia monicaVerrill, 1869, adapted to the carbonate-rich conditions of Mono Lake (CA, USA), and Artemia franciscanaKellogg, 1906, a species broadly distributed in the Americas. The former species has been studied little, despite being listed as threatened in the IUCN Red List. In contrast, the latter has been studied extensively, is broadly distributed in the Americas, and has become established as a non-native invasive species in Europe, Asia, Africa, and Australia. Given the need to conserve A. monica, the intraspecific diversity of invasive A. franciscana, and the local species in areas invaded by this species, we reconsider their biodiversity and taxonomic status currently threatened by synonymization. In conclusion, A. monica and A. franciscana should be treated as two separate species that are isolated both ecologically and reproductively.