Leucosolenida

{{short description|Order of calcareous sponges}}

{{Automatic taxobox

| image = Haeckel_Calcispongiae_Grantia_compressa.jpg

| image_caption = Grantia compressa (Grantiidae)

| taxon = Leucosolenida

| authority = Hartman, 1958

| subdivision_ranks = Families

| subdivision = See text.

}}

Leucosolenida is an order of sponges in the class Calcarea and the subclass Calcaronea.{{Cite web|url=http://www.marinespecies.org/aphia.php?p=taxdetails&id=131591|title=WoRMS - World Register of Marine Species - Leucosolenida|website=www.marinespecies.org|access-date=2019-03-17}} Species in Leucosolenida are calcareous, with a skeleton composed exclusively of free spicules without calcified non-spicular reinforcements.{{Cite journal |last=Borojevic |first=Radovan |last2=Boury-Esnault |first2=Nicole |last3=Vacelet |first3=Jean |date=2000 |title=A revision of the supraspecific classification of the subclass Calcaronea (Porifera, class Calcarea) |url=https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/z2000n2a2.pdf |journal=Zoosystema |volume=22 |issue=2 |pages=203–263}}{{Citation |last=Borojevic |first=Radovan |title=Order Leucosolenida Hartman, 1958 |date=2002 |url=https://doi.org/10.1007/978-1-4615-0747-5_120 |work=Systema Porifera: A Guide to the Classification of Sponges |pages=1157–1184 |editor-last=Hooper |editor-first=John N. A. |access-date=2023-04-28 |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-1-4615-0747-5_120 |isbn=978-1-4615-0747-5 |last2=Boury-Esnault |first2=Nicole |last3=Manuel |first3=Michaël |last4=Vacelet |first4=Jean |editor2-last=Van Soest |editor2-first=Rob W. M. |editor3-last=Willenz |editor3-first=Philippe}}

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. A few sources (such as the Treatise on Invertebrate Paleontology, 2004) place non-asconoid families into a separate order, Sycettida.Treatise on Invertebrate Paleontology Part E, Revised. Porifera, Volume 3: Classes Demospongea, Hexactinellida, Heteractinida & Calcarea, xxxi + 872 p., 506 fig., 1 table, 2004, available [https://journals.ku.edu/InvertebratePaleo/issue/view/455 here]. {{ISBN|0-8137-3131-3}}. Leucosolenids have a poor fossil record, with only a few ambiguous grantiid fossils reported from the Jurassic and Carboniferous.