First Identification of the Alien Species Mimosina affinis Millet, 1900, in the Tyrrhenian Sea

In recent decades, the Mediterranean Sea has been experiencing faunal changes associated with the impact of biological invasions resulting from the influx of invasive alien species (IAS). During the CNR-ISMAR Carg0222 oceanographic cruise, Mimosina affinis, a benthic foraminifera species of Indo-Pacific origin previously reported in more eastern sectors of the Mediterranean, was detected in the Tyrrhenian Sea, at the seafloor off the Italian coast. The study of benthic foraminiferal assemblages, conducted along with sedimentological analysis of seafloor deposits, allowed to reconstruct the distribution of Mimosina affinis in the investigated area and define its relationship with seabed characteristics. The species is commonly found in samples collected at a water depth not shallower than nine metres, showing a preference for silty fine sand sediments. The abundance of the species, in terms of relative abundance, is higher in biocoenoses than in thanatocoenoses, suggesting that the species is established and actively spreading in the studied area.