First records of Ulvella spongophila (Ulvophyceae: Ulvellaceae) for the Palaearctic region: the discovery of four populations in the SW Iberian Peninsula

During extensive Spanish river macrophyte and invertebrate surveys, the freshwater chlorophyte Ulvella spongophila was detected growing inside the freshwater sponge Ephydatia fluviatilis attached to stones. This finding is relevant from the phy¬cological, biogeographical and ecological points of view, and is the second world record of the species after one single known locality (Lake Manindjau, Sumatra, Malaysia), from which the species was collected and described around 130 years ago. The species was collected under summer base-flow conditions in four Mediterranean temporary/seasonal streams in 2018 and 2019. New information about the species’ morphological characteristics and ecological preferences in the Iberian Peninsula is presented. A comparative description of the observed specimens with previously published data, some biogeographical aspects of findings, certain biological facets of the sponge-algal association, and its conservation status, are discussed.