Typification of Porifera described in the 10 edition of Linnaeus’ Systema Naturae, volume II, 1759

The earliest available names for sponges were proposed by Linnaeus in volume II of the 10th edition of his Systema Naturae published in 1759. He described the eleven Spongia species cursorily, and for the illustrations and type localities he referred to pre-1758 works of himself and contemporary authors. Five of the species he erected have been typified by the designation of a lectotype (one species, Spongia lacustris) and neotypes (four species, Spongia officinalis, S. fistulosa, S. muricata and S. fluviatilis), but the remaining six species lacked extant type material and no neotypes have been designated so far (S. oculata, S. nodosa, S. flabelliformis, S. tubulosa, S. aculeata, and S. infundibuliformis). It is the purpose of this study to review and further typify the 1759 Linnean species. In order to clarify the morphological and nomenclatural issues, I traced the history of all eleven species in the pre-1758 and early post-1758 literature and evaluated the information upon which Linnaeus based his 1759 species descriptions. Of all species, images cited by Linnaeus and contemporary authors are reproduced and discussed. Photographs of the (neo-)type specimens and reliably identified in situ or preserved non-type specimens are included. For each species, I include a diagnosis, derived from representative descriptions in the recent literature. Distribution maps downloaded from the World Porifera Database provide the occurrence of the species. Where possible, molecular resources available for these first Linnean species are listed. With the six neotypes proposed for the above-mentioned species the typification of all eleven species erected by Linnaeus in 1759 is completed. The typification process of these earliest species is judged to be of importance for the classification of several speciose poriferan clades, Spongia and Spongiidae, Haliclona and Chalinidae, Ianthella and Ianthellidae, Spongilla and Spongillidae, as well as the ubiquitous genera Amphimedon and Ephydatia.