Editing Demosponge (section)

=== Sclerosponges ===
Sclerosponges were first proposed as a class of sponges, '''Sclerospongiae''', in 1970 by Hartman and Goreau.<ref>{{cite book |last1=Hartman |first1=W.D. |last2=Goreau |first2=T.F. |chapter=Jamaican coralline sponges: Their morphology, ecology and fossil relatives |editor-first=W.G. |editor-last=Fry |title=Biology of the porifera |publisher=Academic Press |series=Symposium of the Zoological Society of London |volume=25 |date=1970 |isbn=0-12-613325-5 |oclc=1409104310 |pages=205–243 }} (Cited by {{cite web |url=http://mgg.rsmas.miami.edu/groups/sil/work1.htm |date=21-23 March 1998 |title=Notes of the ''Sclerosponge Workshop'' |publisher=University of Miami |department=Stable Isotope Laboratory, Rosenstiel School of Marine and Atmospheric Science |location=Miami, FL |access-date=2018-12-19 |df=dmy-all |archive-date=2018-08-18 |archive-url=https://web.archive.org/web/20180818135926/http://mgg.rsmas.miami.edu/groups/sil/work1.htm |url-status=dead }})</ref> However, it was later found by Vacelet that sclerosponges occur in different classes of [[Porifera]].<ref>{{cite conference |first=J. |last=Vacelet |title=Coralline sponges and the evolution of the Porifera |book-title=The origins and relationships of lower invertebrates : Proceedings of an International symposium held in London, September 1983 |series=Systematics Association |volume=28 |publisher=Clarendon Press |date=1985 |isbn=0-19-857181-X |oclc=220503346 |pages=1–13 }}</ref> That means that sclerosponges are not a closely related ([[Taxonomy (biology)|taxonomic]]) group of sponges and are considered to be a polyphyletic grouping and contained within the Demospongiae. Like [[bat]]s and [[bird]]s that independently developed the ability to fly, different sponges developed the ability to build a calcareous skeleton independently and at different times in [[Geological history of Earth|Earth's history]]. Fossil sclerosponges are already known from the [[Cambrian]] period.<ref>{{cite journal |first=J. |last=Reitner |title=Coralline Spongien — Der Versuch einer phylogenetisch-taxonomischen Analyse |journal=Berliner geowissenschaftliche Abhandlungen. Reihe e, Paläobiologie |volume=1 |date=1992 |doi=10.23689/fidgeo-5876 |url=https://e-docs.geo-leo.de/handle/11858/11466}}<!-- Yes, the very first paper to appear in this journal! See http://userpage.fu-berlin.de/~palaeont/JOURNAL.HTM --></ref>