Porifera of Greece: an updated checklist

Background The checklist of Porifera of Greece was created in the framework of the Greek Taxon Information System (GTIS), an initiative of the LifeWatchGreece Research Infrastructure (ESFRI) that has resumed efforts to compile a complete checklist of species recorded from Greece. An updated checklist of Porifera was created on the basis of a list of the Aegean Demospongiae and Homoscleromorpha published one decade ago. All records of species known to occur in Greek waters were taxonomically validated and cross-checked for possible inaccuracies and omissions. Then, all recent publications were reviewed and the species recorded from 2006 to date were added to the list. New information The updated checklist of Porifera of Greece comprises 215 species, classified to 111 genera, 65 families, 24 orders, and 4 classes. In total, 34 new additions were made to the previous species list (8 Calcarea, 17 Demospongiae, 1 Hexactinellida, and 6 Homoscleromorpha) with Calcarea being listed for the first time from the area. The demosponge orders Poecilosclerida, Dictyoceratida, Tetractinellida, Haplosclerida, and Suberitida have the highest number of species covering 62% of the known Greek sponge species richness. It is worth mentioning that 8 species have been first described from Greek waters, 7 of which are considered endemic to this area. Our bibliographic overview also revealed knowledge gaps with regard to specific habitats typically rich in sponge diversity, and marine sectors of Greece.