The moon jellyfish Aurelia (Cnidaria, Scyphozoa) species complex is widely distributed.
The current study analyzed through molecular techniques polyps, ephyrae, and medusae collected in the Mediterranean Sea, revealing different phylogenetic species. Evidence was found for three Aurelia species, none of which are referable to the type species of the genus, Aurelia aurita; the identification of Aurelia coerulea and Aurelia solida as established non indigenous species in the Mediterranean Sea was revealed.
An extra species, new for science, was also described: Aurelia relicta, endemic to a marine lake of Croatia.
These results demonstrate the usefulness of integrative approaches in resolving taxonomic uncertainty surrounding cryptic species complexes, identifying patterns of marine biodiversity, and recognizing non-indigenous species in marine ecosystems.