Stellispongiida is an order of calcareous sponges, most or all of which are extinct. Stellispongiids are one of several unrelated sponge groups described as "inozoans", a name referring to sponges with a hypermineralized calcitic skeleton independent from their spicules. Stellispongiids have a solid skeleton (without chambers) encasing

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

spicules arranged in trabeculae (column-like structures).''Treatise on Invertebrate Paleontology'' Part E, Revised. Porifera, Volume 3: Classes Demospongea, Hexactinellida, Heteractinida & Calcarea, xxxi + 872 p., 506 fig., 1 table, 2004, availabl
here
.''Treatise on Invertebrate Paleontology'' Part E, Revised. Porifera, Volumes 4 & 5: Hypercalcified Porifera, Paleozoic Stromatoporoidea & Archaeocyatha, liii + 1223 p., 665 figs., 2015, availabl
here
. "Inozoans" and the similar "sphinctozoans" were historically grouped together in the

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

order Pharetronida. Stellispongiids survived from the Permian to the

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

, at least up to the Miocene Epoch. They comprised the majority of "inozoan" diversity in the

Cretaceous Period The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geologi ...

, though their distribution was mostly restricted to Europe. The ''

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

'' (2004) places the living sponge family Lelapiidae within Stellispongiida, though ''Systema Porifera'' (2002) places Lelapiidae within the order

Leucosolenida Leucosolenida is an order of sponges in the class Calcarea and the subclass Calcaronea. Species in Leucosolenida are calcareous, with a skeleton composed exclusively of free spicules without calcified non-spicular reinforcements. According to ...

Subgroups

* Family † Endostomatidae Finks & Rigby, 2004 nowiki/>Lower Triassic?–Eocene">Lower_Triassic.html" ;"title="nowiki/>Lower Triassic">nowiki/>Lower Triassic?–Eocene] * Family Lelapiidae? Dendy & Row, 1913 [Holocene] * Family †Stellispongiidae Laubenfels, 1955 nowiki/>Permian–Miocene">Permian.html" ;"title="nowiki/>Permian">nowiki/>Permian–Miocene]

References

{{Taxonbar, from=Q19328554 Calcaronea Sponge orders Prehistoric animal orders