# Hexasterophora > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Hexasterophora > Markdown URL: https://mediated.wiki/source/Hexasterophora.md > Source: https://en.wikipedia.org/wiki/Hexasterophora > Source revision: 1292886321 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Subclass of Hexactinellid sponges}} {{More citations needed|type=animal|date=December 2009}} {{Automatic taxobox | fossil_range = {{fossil range | Ordovician | Recent | refs = {{Cite Q|Q111529763|last1=Botting |first1=J. P. |last2=Janussen |first2=D. |last3=Muir |first3=L. A. |last4=Dohrmann |first4=M. |last5=Ma |first5=J. |last6=Zhang |first6=Y.}}}} | image = Haeckel Hexactinellae.jpg | image_caption = | taxon = Hexasterophora | authority = Schulze, 1886 | subdivision_ranks = Subgroups | subdivision = * Order [Lychniscosida](/source/Lychniscosida) * Order [Lyssacinosida](/source/Lyssacinosida) * Order [Sceptrulophora](/source/Sceptrulophora) * ''incertae sedis'' ** Family [Dactylocalycidae](/source/Dactylocalycidae) | synonyms = * Aulocalycoida Tabachnick & Reiswig, 2000{{cite web |title=WoRMS - World Register of Marine Species - Aulocalycoida |url=https://www.marinespecies.org/aphia.php?p=taxdetails&id=171606 |website=www.marinespecies.org |access-date=11 June 2021}} * Hexactinosida Schrammen, 1912 {{cite web |title=WoRMS - World Register of Marine Species - Hexactinosida |url=https://www.marinespecies.org/aphia.php?p=taxdetails&id=171628 |website=www.marinespecies.org |access-date=11 June 2021 |language=en}} }} [[File:Hexactinellida diversity.png|left|thumb|''[Atlantisella](/source/Atlantisella)'' (order Lyssacinosida, C), ''[Lefroyella](/source/Lefroyella)'' (order Sceptrulophora, D), and a hexaster microsclere (A, left) in a collage of hexactinellids.]] '''Hexasterophora''' are a [subclass](/source/Class_(biology)) of glass [sponges](/source/Sponge) in the class [Hexactinellida](/source/Hexactinellida). Most living hexasterophorans can be divided into three orders: [Lyssacinosida](/source/Lyssacinosida), [Lychniscosida](/source/Lychniscosida), and [Sceptrulophora](/source/Sceptrulophora).{{Cite journal |last1=Dohrmann |first1=Martin |last2=Janussen |first2=Dorte |last3=Reitner |first3=Joachim |last4=Collins |first4=Allen G. |last5=Wörheide |first5=Gert |date=2008 |editor-last=Anderson |editor-first=Frank |title=Phylogeny and Evolution of Glass Sponges (Porifera, Hexactinellida) |journal=Systematic Biology |language=en |volume=57 |issue=3 |pages=388–405 |doi=10.1080/10635150802161088 |issn=1076-836X|doi-access=free |pmid=18570034 }} Like other glass sponges, hexasterophorans have skeletons composed of overlapping six-rayed [spicule](/source/spicule_(sponge))s. In addition, they can be characterized by the presence of hexasters, a type of [microsclere](/source/microsclere) (microscopic spicules) with six rays unfurling into multi-branched structures.{{Cite journal |last1=Łukowiak |first1=Magdalena |last2=Van Soest |first2=Rob |last3=Klautau |first3=Michelle |last4=Pérez |first4=Thierry |last5=Pisera |first5=Andrzej |last6=Tabachnick |first6=Konstantin |date=2022 |title=The terminology of sponge spicules |url=https://onlinelibrary.wiley.com/doi/10.1002/jmor.21520 |journal=Journal of Morphology |language=en |volume=283 |issue=12 |pages=1517–1545 |doi=10.1002/jmor.21520 |pmid=36208470 |issn=0362-2525|url-access=subscription }} A living sponge is commonly firmly attached by its base to a hard [substratum](/source/substrate_(biology)); less often rooted by the anchoring spicules and rarely inserted directly into the loose bottom sediments. The three orders are differentiated by the extent to which adjacent spicules have fused. The oldest order, without fused spicules, is Lyssacinosida (or Lyssacinosa), which appears in the [Ordovician](/source/Ordovician). The other two orders have fully fused their spicules into a framework of dictyonal strands. The most fused order is Lychniscosida (or Lychniscosa), which develops octahedral frames (lychniscs) around the nodes between their dictyonal strands. Lychniscosa fossils first appeared in the [Middle Jurassic](/source/Middle_Jurassic).{{Cite journal |last=Pisera |first=A |date=2006-02-01 |title=Palaeontology of sponges — a review |url=http://www.nrcresearchpress.com/doi/10.1139/z05-169 |journal=Canadian Journal of Zoology |language=en |volume=84 |issue=2 |pages=242–261 |doi=10.1139/z05-169 |bibcode=2006CaJZ...84..242P |issn=0008-4301|url-access=subscription }}{{Citation |last=Krautter |first=Manfred |title=Fossil Hexactinellida: An Overview |date=2002 |url=http://link.springer.com/10.1007/978-1-4615-0747-5_124 |work=Systema Porifera |pages=1211–1223 |editor-last=Hooper |editor-first=John N. A. |access-date=2023-05-02 |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-1-4615-0747-5_124 |isbn=978-0-306-47260-2 |editor2-last=Van Soest |editor2-first=Rob W. M. |editor3-last=Willenz |editor3-first=Philippe|url-access=subscription }} Sponges intermediate between these two extremes were historically placed into the order Hexactinosa (or Hexactinosida). Genetic sequencing has determined that this proposed order is [polyphyletic](/source/polyphyletic), with its constituents split between the valid order [Sceptrulophora](/source/Sceptrulophora) (bearing sceptrules) and the family [Dactylocalycidae](/source/Dactylocalycidae) (lacking sceptrules). The oldest "hexactinosan" fossils are from the [Devonian](/source/Devonian).''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}}. ==References== {{Reflist}} {{Taxonbar|from=Q1616691}} Category:Hexactinellida Category:Sponge subclasses {{Sponge-stub}} --- Adapted from the Wikipedia article [Hexasterophora](https://en.wikipedia.org/wiki/Hexasterophora) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Hexasterophora?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.