Genetic identification of South African Artemia species: invasion, replacement and co-occurrence

Detailed molecular data of Artemia (Crustacea, Anostraca) from South Africa are scarce. Here, we provide for the first time genetic data on the species status and phylogeography of Artemia from this region after an extensive sampling expedition. Our 16S rRNA RFLP analysis of 27 Artemia populations, including seven from South African sites, provides evidence for the presence of a mixed bisexual and parthenogenetic component in this area. Phylogenetic and network analyses reveal that three (out of seven) Artemia populations from South Africa belong to the invasive A. franciscana, two of them belong to A. salina while the last two contain both parthenogenetic and bisexual (A. salina) individuals. From a total of 18 haplotypes identified, seven were recorded from South Africa. To our knowledge, this is the first confirmed report of A. franciscana in this region. Its invasiveness is reaffirmed by evidence for the complete replacement of the native A. salina population from Velddrif Saltworks. However, in other cases, parthenogens seem to modify the capacity of A. franciscana to replace natives. Results on the genetic identification of South African Artemia provide insights into the dynamics of invasion and co-occurrence and highlight effects on species interactions and on biodiversity in inland aquatic invertebrates.