First known free-living lithistid sponge

PUBLICATION — Andrzej Pisera, Magdalena Łukowiak 2025. Shallow-water lithistid demosponges from the NW Indian Ocean (Cape Guardafui): taxonomy, biogeography, and the first record of free-living forms, Continental Shelf Research, 294, 2025, 105537. https://doi.org/10.1016/j.csr.2025.105537.

Figure: habitus of the studied sponges. A–C, I–J, Gastrophanella somaliensis sp. nov., D–H, Microscleroderma magnum sp. nov.

Lithistids, an informal grouping of demosponges, are sponges with skeletons built of articulated spicules. Typically they are found in deep waters, but off the Somali coast we discovered six species inhabiting sandy sea-bottom at a depth of 50 metres. Three of them are proposed as new. One, Microscleroderma magnum, was found living unattached—the first recorded free-living lithistid. The assemblage composition differs from that of African and Indian Ocean coasts, though some similarities to nearby regions are evident.