Leucosolenida is an order of sponges in the class Calcarea and the subclass Calcaronea.[1] Species in the order Leucosolenida are calcareous, with a skeleton composed exclusively of free spicules without calcified non-spicular reinforcements.[2][3]
According to Systema Porifera (2002), Lucosolenida contains 9 families, ranging from fully asconoid forms (Leucosoleniidae) to fully leuconoid forms. These body plans are on a continuum based on an increasingly complex skeletal system and compartmentalized choanocytes.[3] A few sources (such as the Treatise on Invertebrate Paleontology, 2004) place non-asconoid families into a separate order, Sycettida.[4] Leucosolenids have a poor fossil record, with only a few ambiguous grantiid fossils reported from the Jurassic and Carboniferous.[4]