Calcareous sponge

All sponges in this class are strictly marine, and, while they are distributed worldwide, most are found in shallow tropical waters. Like nearly all other sponges, they are sedentary filter feeders.

All three sponge body plans (asconoid, syconoid, and leuconoid) can be found within the class Calcarea. Typically, calcareous sponges are small, measuring less than {{convert|10|cm|in|abbr=on}} in height, and drab in colour. However, a few brightly coloured species are also known.

Like the Homoscleromorpha, calcareous sponges are exclusively viviparous.[https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-022-01291-6 Symbiont transmission in marine sponges: reproduction, development, and metamorphosis]

Calcareous sponges vary from radially symmetrical vase-shaped body types to colonies made up of a meshwork of thin tubes, or irregular massive forms. The skeleton has either a mesh or honeycomb structure of interlocking spicules.{{cite book |last1=Ruppert |first1=Edward |last2=Fox |first2=Richard |last3=Barnes |first3=Robert |title=Invertebrate Zoology: A Functional Evolutionary Approach |date=2003 |publisher=Cengage Learning |isbn=978-0030259821 |edition=7th}} Some extinct species were hypercalcified, meaning that the spicule-based skeleton is cemented together by solid calcite.

Of the approximately 11,000 living species of Porifera, only around 800 are calcareans. Some older studies applied the name Calcispongiae to the class, though "Calcarea" is much more common in modern nomenclature.

Calcarean sponges likely first appeared during the Cambrian Period. The oldest putative calcarean genus is Gravestockia, from the "Atdabanian" (Cambrian Stage 3) of Australia. Calcareans are probably descended from "heteractinid" sponges, which first appeared in the early Cambrian.{{Cite journal |last=Nadhira |first=Ardianty |last2=Sutton |first2=Mark D. |last3=Botting |first3=Joseph P. |last4=Muir |first4=Lucy A. |last5=Gueriau |first5=Pierre |last6=King |first6=Andrew |last7=Briggs |first7=Derek E. G. |last8=Siveter |first8=David J. |last9=Siveter |first9=Derek J. |date=2019 |title=Three-dimensionally preserved soft tissues and calcareous hexactins in a Silurian sponge: implications for early sponge evolution |url=https://royalsocietypublishing.org/doi/10.1098/rsos.190911 |journal=Royal Society Open Science |language=en |volume=6 |issue=7 |pages=190911 |doi=10.1098/rsos.190911 |issn=2054-5703 |pmc=6689616 |pmid=31417767}} Calcareans reached their greatest diversity during the Cretaceous period.

Some molecular analyses suggest the class Calcarea is not exclusively related to other sponges, and should thus be designated as a phylum. This would also render Porifera (the sponge phylum) paraphyletic. Borchiellini et al. (2001) argued that calcareans were more closely related to Eumetazoa (non-sponge animals) than to other sponges.{{Cite journal |last=Borchiellini |first=C. |last2=Manuel |first2=M. |last3=Alivon |first3=E. |last4=Boury-Esnault |first4=N. |last5=Vacelet |first5=J. |last6=Le Parco |first6=Y. |date=2001-01-08 |title=Sponge paraphyly and the origin of Metazoa: Sponge paraphyly |url=http://doi.wiley.com/10.1046/j.1420-9101.2001.00244.x |journal=Journal of Evolutionary Biology |language=en |volume=14 |issue=1 |pages=171–179 |doi=10.1046/j.1420-9101.2001.00244.x|doi-access=free }} A few studies have also supported a sister group relationship between calcareans and Ctenophora (comb jellies). Many authors have strongly doubted the hypothesis of sponge paraphyly, arguing that genetic studies have incomplete sampling and are incompatible with the unique anatomical traits shared by living sponges.{{Citation |last=Wörheide |first=G. |title=Deep Phylogeny and Evolution of Sponges (Phylum Porifera) |date=2012 |url=http://dx.doi.org/10.1016/b978-0-12-387787-1.00007-6 |work=Advances in Sponge Science: Phylogeny, Systematics, Ecology |pages=1–78 |access-date=2023-04-28 |publisher=Elsevier |last2=Dohrmann |first2=M. |last3=Erpenbeck |first3=D. |last4=Larroux |first4=C. |last5=Maldonado |first5=M. |last6=Voigt |first6=O. |last7=Borchiellini |first7=C. |last8=Lavrov |first8=D.V.}}

Calcarea is divided into two subclasses (Calcinea and Calcaronea) and a number of orders. The two subclasses are mainly distinguished by spicule orientation, soft tissue and developmental traits. For example, calcineans develop from a parenchymella (a larva with a solid center and radial symmetry). Calcaroneans, on the other hand, develop from an amphiblastula (a larva with a hollow center and semi-bilateral symmetry).Treatise on Invertebrate Paleontology Part E, Revised. Porifera, Volume 2: Introduction to the Porifera, xxvii + 349 p., 135 fig., 10 tables, 2003, available [https://journals.ku.edu/InvertebratePaleo/issue/view/454 here]. {{ISBN|0-8137-3130-5}}.

Class Calcarea

• Subclass Calcinea
• Order Clathrinida [Holocene]
• Order Murrayonida [Holocene]
• Subclass Calcaronea
• Order Baerida [Pleistocene–Holocene]
• Order Leucosolenida / Sycettida [Carboniferous?–Holocene]
• Incertae sedis
• Order Lithonida [Jurassic–Holocene]
• Order †Sphaerocoeliida [Permian–Cretaceous]
• Order †Stellispongiida [Permian–Holocene?]
• Genus †Gravestockia [Cambrian]

File:Clathrina clathrus (Schmidt, 1864) et Hemimycale columella (Bowerbank, 1874).jpg|Clathrina clathrus (order Clathrinida)

File:Clathrina lacunosa 111198014.jpg|Clathrina lacunosa (order Clathrinida)

File:Leucetta chagosensis (10.11646-zootaxa.4426.1.1) Figure 43.jpg|Leucetta chagosensis (order Clathrinida)

File:Calcareous Sponge (Leucetta primigenia) (8478940474).jpg|Leucetta primigenia (order Clathrinida)

File:Leucosolenia botryoides 43980050.jpg|Leucosolenia botryoides (order Leucosolenida)

File:Leucandra losangelensis 214277336.jpg|Leucandra losangelensis (order Leucosolenida)

File:Sycon ciliatum 29886028.jpg|Sycon ciliatum (order Leucosolenida)

File:Urn Sponge (Leucilla nuttingi) (8371714007).jpg|Leucilla nuttingi (order Leucosolenida)

File:Jurassic Calcarea Matmor Israel.jpg|Unidentified calcarean fossil (with encrusting crinoid) from the Jurassic of Israel

File:Matmor_calcisponge_Peronidella.jpg|†Peronidella fossil (order †Stellispongiida) from the Jurassic of Israel

File:Fossil Porosphaera Globularis Rethen (Vordorf), Germany.jpg|†Porosphaera globularis fossil (order Lithonida) from the Cretaceous of Germany

{{reflist}}

• [http://www.ucmp.berkeley.edu/porifera/calcarea.html UCMP: Calcarea]

{{Wikispecies|Calcarea}}

{{Commons category|Calcarea}}

{{Porifera}}

{{Animalia}}

{{Taxonbar|from=Q209924}}

Category:Taxa named by James Scott Bowerbank