Addition to Sweden’s freshwater sponge fauna and a phylogeographic study of Spongilla lacustris (Spongillida, Porifera) in southern Sweden Author Robert, Chloé 384E6BC8-C928-4D4E-B7DB-BC285556ABCB Dept. Organismal Biology, Uppsala University, Norbyvägen 18 D, SE- 752 36 Uppsala, Sweden. & Dept. Marine Sciences, University of Gothenburg, Box 461, SE- 405 30 Göteborg, Sweden. chloe.robert@gu.se Author Pereira, Raquel 2E0077C7-7540-4E45-B3B0-32A4A4F1D50B Dept. Organismal Biology, Uppsala University, Norbyvägen 18 D, SE- 752 36 Uppsala, Sweden. raquel.pereira@ebc.uu.se Author Thollesson, Mikael C1EF10A0-3D59-4C66-A2A6-2BD48F154721 Dept. Organismal Biology, Uppsala University, Norbyvägen 18 D, SE- 752 36 Uppsala, Sweden. mikael.thollesson@ebc.uu.se text European Journal of Taxonomy 2022 2022-07-13 828 1 138 167 http://dx.doi.org/10.5852/ejt.2022.828.1861 journal article 97042 10.5852/ejt.2022.828.1861 db902fb6-703b-4457-a4e8-37be2a702d74 2118-9773 6839811 92E8908C-818C-49CD-8E84-A95479F8E455 Ephydatia fluviatilis ( Linnaeus, 1759 ) Fig. 3 Spongia fluviatilis Linnaeus, 1759: 1348 . Material examined ( 4 specimens , Table 1 ) SWEDEN – Stockholm • 3 specs ; Helgarsviken ; 59.289° N , 18.7032° E ; 2 Sep. 2017 ; Raquel Pereira leg.; UPSZMC 188229 , 188231 , 188233 • 1 spec. ; Stavsnäs vinterhamn ; 59.2889° N , 18.7062° E ; 31 Dec. 2021 ; Raquel Pereira and Jesper Svedberg leg.; UPSZMC 189246 Description HABITUS. Colour from pale to brownish, encrusting ( Fig. 3A ). SPICULAE. Megascleres and gemmuloscleres. Megascleres thin, smooth and acute oxeas ( Fig. 3B ), 250 μm (60–360 μm) long ( Fig. 3C ), 7.5 μm (2–15 μm) wide. Very few gemmuloscleres found in the collected specimens; birotulated, often a spine on the shaft, 20 µm long and 25 μm wide. Distribution and habitats This species was only found in the Baltic, but was missing from the bona fide freshwater samples. Remarks Five specimens from inland waters tentatively identified as E. fluviatilis (based on megasclers only, lacking gemmulae) was reassigned to Eunapius fragilis based on bar-coding sequences and a re-scrutiny of spiculae, so there is a possibility that some previously reported specimens of this (in Sweden ) rare species may be misidentifications. It is quite possible, however, that it is present at greater depth at some of the sites, and thus missed in our study – the specimens from the Baltic were all from greater depths. We note, though, that Arndt (1932) only listed specimens from seven sites, all but one site outside (south of) the present study area, so the lack of observations may reflect a rare occurrence.