Thecalcareoussponges[2][3](classCalcarea) are members of the animal phylumPorifera,the cellular sponges. They are characterized byspiculesmade ofcalcium carbonate,in the form of high-magnesiumcalciteoraragonite.While the spicules in most species are triradiate (with three points in a single plane), some species may possess two- or four-pointed spicules.[4][5]Unlike other sponges, calcareans lack microscleres, tiny spicules which reinforce the flesh. In addition, their spicules develop from the outside-in, mineralizing within a hollow organic sheath.[6]
| Calcareous sponges | |
|---|---|
| |
| "Calcispongiae" fromErnst Haeckel'sKunstformen der Natur,1904 | |
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Porifera |
| Class: | Calcarea Bowerbank,1864 |
| Subclasses | |
Biology
editAll 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 sedentaryfilter feeders.
All threesponge body plans(asconoid,syconoid,andleuconoid) can be found within the class Calcarea. Typically, calcareous sponges are small, measuring less than 10 cm (3.9 in) in height, and drab in colour. However, a few brightly coloured species are also known.
Like theHomoscleromorpha,calcareous sponges are exclusivelyviviparous.[7]
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.[3]Some extinct species were hypercalcified, meaning that the spicule-based skeleton is cemented together by solid calcite.[5]
Classification
editOf the approximately 15,000 living species of Porifera, only around 400 are calcareans. Some older studies applied the nameCalcispongiaeto the class, though "Calcarea" is much more common in modern nomenclature.
Calcarean sponges likely first appeared during theCambrian Period.The oldest putative calcarean genus isGravestockia,from the "Atdabanian"(Cambrian Stage 3) of Australia.[4]Calcareans are probably descended from "heteractinid"sponges, which first appeared in the early Cambrian.[6][8]Calcareans reached their greatest diversity during theCretaceous period.
Some molecular analyses suggest the class Calcarea is not exclusively related to other sponges, and should thus be designated as aphylum.This would also render Porifera (the sponge phylum)paraphyletic.Borchiellini et al. (2001) argued that calcareans were more closely related toEumetazoa(non-sponge animals) than to other sponges.[9]A few studies have also supported a sister group relationship between calcareans andCtenophora(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.[10]
Calcarea is divided into two subclasses (Calcinea and Calcaronea) and a number of orders.[4][5]The two subclasses are mainly distinguished by spicule orientation, soft tissue and developmental traits. For example, calcineans develop from aparenchymella(alarvawith 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).[11][4]
ClassCalcarea
- SubclassCalcinea
- OrderClathrinida[Holocene]
- OrderMurrayonida[Holocene]
- SubclassCalcaronea
- OrderBaerida[Pleistocene–Holocene]
- OrderLeucosolenida/Sycettida[Carboniferous?–Holocene]
- Incertae sedis
- OrderLithonida[Jurassic–Holocene]
- Order †Sphaerocoeliida[Permian–Cretaceous]
- Order †Stellispongiida[Permian–Holocene?]
- Genus †Gravestockia[Cambrian]
Gallery
edit-
Clathrina clathrus(order Clathrinida) -
Clathrina lacunosa(order Clathrinida) -
Leucetta chagosensis(order Clathrinida) -
Leucetta primigenia(order Clathrinida) -
Leucosolenia botryoides(order Leucosolenida) -
Leucandra losangelensis(order Leucosolenida) -
Sycon ciliatum(order Leucosolenida) -
Leucilla nuttingi(order Leucosolenida) -
Unidentified calcarean fossil (with encrustingcrinoid) from the Jurassic of Israel -
†Peronidellafossil (order †Stellispongiida) from the Jurassic of Israel -
†Porosphaera globularisfossil (order Lithonida) from the Cretaceous of Germany
References
edit- ^"Calcarea".paleobiodb.org.Retrieved2021-08-22.
- ^Richard Hertwig (1912).A Manual of Zoology.Translated by J. S. Kingsley. New York: Henry Holt & Co. p.204.
Thecalc spongesare exclusively marine and mostly live in shallow water.
- ^abRuppert, Edward; Fox, Richard; Barnes, Robert (2003).Invertebrate Zoology: A Functional Evolutionary Approach(7th ed.). Cengage Learning.ISBN978-0030259821.
- ^abcdTreatise on Invertebrate PaleontologyPart E, Revised. Porifera, Volume 3: Classes Demospongea, Hexactinellida, Heteractinida & Calcarea, xxxi + 872 p., 506 fig., 1 table, 2004, availablehere.ISBN0-8137-3131-3.
- ^abcTreatise on Invertebrate PaleontologyPart E, Revised. Porifera, Volumes 4 & 5: Hypercalcified Porifera, Paleozoic Stromatoporoidea & Archaeocyatha, liii + 1223 p., 665 figs., 2015, availablehere.ISBN978-0-9903621-2-8.
- ^abBotting, Joseph P.; Butterfield, Nicholas J. (2005)."Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott".Proceedings of the National Academy of Sciences.102(5): 1554–1559.doi:10.1073/pnas.0405867102.ISSN0027-8424.PMC547825.PMID15665105.
- ^Symbiont transmission in marine sponges: reproduction, development, and metamorphosis
- ^Nadhira, Ardianty; Sutton, Mark D.; Botting, Joseph P.; Muir, Lucy A.; Gueriau, Pierre; King, Andrew; Briggs, Derek E. G.; Siveter, David J.; Siveter, Derek J. (2019)."Three-dimensionally preserved soft tissues and calcareous hexactins in a Silurian sponge: implications for early sponge evolution".Royal Society Open Science.6(7): 190911.doi:10.1098/rsos.190911.ISSN2054-5703.PMC6689616.PMID31417767.
- ^Borchiellini, C.; Manuel, M.; Alivon, E.; Boury-Esnault, N.; Vacelet, J.; Le Parco, Y. (2001-01-08)."Sponge paraphyly and the origin of Metazoa: Sponge paraphyly".Journal of Evolutionary Biology.14(1): 171–179.doi:10.1046/j.1420-9101.2001.00244.x.
- ^Wörheide, G.; Dohrmann, M.; Erpenbeck, D.; Larroux, C.; Maldonado, M.; Voigt, O.; Borchiellini, C.; Lavrov, D.V. (2012),"Deep Phylogeny and Evolution of Sponges (Phylum Porifera)",Advances in Sponge Science: Phylogeny, Systematics, Ecology,Elsevier, pp. 1–78,retrieved2023-04-28
- ^Treatise on Invertebrate PaleontologyPart E, Revised.Porifera,Volume 2: Introduction to the Porifera, xxvii + 349 p., 135 fig., 10 tables, 2003, availablehere.ISBN0-8137-3130-5.
External links
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