Range expansion of two non-indigenous sponges (Porifera) in southern European waters: new records from the Atlantic coast of the Iberian Peninsula

The Atlantic coast of the Iberian Peninsula is a region susceptible to the introduction of non-indigenous species (NIS). However, records of NIS sponges remain scarce and often lack of morphological confirmation. Here, we provide evidence for the presence of two NIS sponges, Haliclona (Chalinula) loosanoffi (Demospongiae: Haplosclerida) and Paraleucilla magna (Calcarea: Leucosolenida) in this area, based on surveys conducted in natural and artificial habitats from the Bay of Cádiz to Galicia. Haliclona loosanoffi is native to the northeastern United States and has been previously recorded in northern European waters. In the present study, it was found in northern Portugal, extending its known range southwards. Paraleucilla magna was originally described from Brazil and is now widely distributed in the Mediterranean Sea. Here, it was found in southern Spain and Portugal, and northwestern Spain, representing its northernmost Atlantic occurrence. Both species were predominantly associated with recreational marinas and mussel rafts, highlighting the role of anthropogenic activities in their spread. However, several specimens of Paraleucilla magna were also collected in natural habitats. In addition, worldwide records of both species were compiled from their original descriptions to the present to update their distribution ranges. Our findings extend the known ranges of both NIS in southern European waters, improve the knowledge of Porifera, and emphasize the importance of morphological approaches for invasion management.