A new species of Leucosoleniidae, Leucosolenia microspinata sp. nov., from the southern Tyrrhenian Sea (Porto Vecchio pond, Marinello Marine Reserve, Messina) is here described. The species consists of a dense reticulation of ascon tubes having a colour ranging from white-cream to light-brown. Its spiculation consists of diactines sometimes serrated or microspined, not separable into size-classes, triactines of four types and tetractines with microspined apical actine. The comparison with other Mediterranean Leucosolenia is reported.
