Editing Foraminifera (section)

==Tests==
{{main|Foraminifera test}}
{{see also|Protist shell}}
[[File:benthic foraminifera.jpg|thumb|upright=1.2| {{center|Foraminiferan tests (ventral view)}}]]
{{biomineralization sidebar|exoskeletons}}

Foraminiferal [[Test (biology)|tests]] serve to protect the organism within. Owing to their generally hard and durable construction (compared to other protists), the tests of foraminifera are a major source of scientific knowledge about the group.

Openings in the test that allow the cytoplasm to extend outside are called apertures.<ref name="Lana2001">{{Cite journal|last1=Lana|first1=C|year=2001|title=Cretaceous Carterina (Foraminifera)|journal=Marine Micropaleontology|volume=41|issue=1–2|pages=97–102|bibcode=2001MarMP..41...97L|doi=10.1016/S0377-8398(00)00050-5}}</ref> The ''primary'' aperture, leading to the exterior, take many different shapes in different species, including but not limited to rounded, crescent-shaped, slit-shaped, hooded, radiate (star-shaped), dendritic (branching). Some foraminifera have "toothed", flanged, or lipped primary apertures. There may be only one primary aperture or multiple; when multiple are present, they may be clustered or equatorial. In addition to the primary aperture, many foraminifera have ''supplemental'' apertures. These may form as relict apertures (past primary apertures from an earlier growth stage) or as unique structures.

Test shape is highly variable among different foraminifera; they may be single-chambered (unilocular) or multi-chambered (multilocular). In multilocular forms, new chambers are added as the organism grows. A wide variety of test morphologies is found in both unilocular and multilocular forms, including spiraled, serial, and milioline, among others.<ref name=Saraswati2016 />

Many foraminifera exhibit dimorphism in their tests, with megalospheric and microspheric individuals. These names should not be taken as referring to the size of the full organism; rather, they refer to the size of the first chamber, or ''proloculus''. Tests as fossils are known from as far back as the [[Ediacaran]] period,<ref name=Kontorovich2008>{{Cite journal|last1=Kontorovich|first1=A. E.|last2=Varlamov|first2=A. I.|last3=Grazhdankin|first3=D. V.|last4=Karlova|first4=G. A.|last5=Klets|first5=A. G.|last6=Kontorovich|first6=V. A.|last7=Saraev|first7=S. V.|last8=Terleev|first8=A. A.|last9=Belyaev|first9=S. Yu.|last10=Varaksina|first10=I. V.|last11=Efimov|first11=A. S.|date=2008-12-01|title=A section of Vendian in the east of West Siberian Plate (based on data from the Borehole Vostok 3)|url=http://www.sciencedirect.com/science/article/pii/S106879710800206X|journal=Russian Geology and Geophysics|language=en|volume=49|issue=12|pages=932–939|doi=10.1016/j.rgg.2008.06.012|bibcode=2008RuGG...49..932K|issn=1068-7971|url-access=subscription}}</ref> and many marine sediments are composed primarily of them.  For instance, the limestone that makes up the pyramids of Egypt is composed almost entirely of [[Nummulite|nummulitic]] benthic Foraminifera.<ref>[http://www.ucl.ac.uk/GeolSci/micropal/foram.html#histofstudy Foraminifera: History of Study], [[University College London]], retrieved 20 September 2007</ref> It is estimated that reef Foraminifera generate about 43 million tons of calcium carbonate per year.<ref name="Langer. et al. 1997">{{Cite journal|title = Global ocean carbonate and carbon dioxide production: The role of reef Foraminifera |year = 1997|last= Langer|first=M. R.|author2=Silk, M. T. B. |author3=Lipps, J. H. |journal = Journal of Foraminiferal Research|volume = 27|issue = 4|pages = 271–277|doi = 10.2113/gsjfr.27.4.271| bibcode=1997JForR..27..271L |url=http://jfr.geoscienceworld.org/cgi/content/abstract/27/4/271|url-access = subscription}}</ref>

Genetic studies have identified the naked amoeba ''[[Reticulomyxa]]'' and the peculiar [[xenophyophore]]s as foraminiferans without tests. A few other amoeboids produce reticulose pseudopods, and were formerly classified with the forams as the Granuloreticulosa, but this is no longer considered a natural group, and most are now placed among the Cercozoa.<ref name="Adl. et al.">{{Cite journal|title = The new higher level classification of Eukaryotes with emphasis on the taxonomy of Protists|year = 2005|last= Adl|first=S. M.|author2=Simpson, A. G. B. |author3=Farmer, M. A. |author4=Anderson  |journal = Journal of Eukaryotic Microbiology|volume = 52|issue = 5|pages = 399–451|doi = 10.1111/j.1550-7408.2005.00053.x|pmid = 16248873|s2cid = 8060916|display-authors=etal|doi-access = free}}</ref>