{{Short description|Genus of algae}} {{Automatic taxobox | image =Coelastrum okular.jpg | image_alt= Coenobium of Coelastrum sp. | image_caption= coenobium of ''Coelastrum'' sp. | taxon = Coelastrum | authority = Nägeli, 1849 | type_species = ''Coelastrum sphaericum'' | type_species_authority = Nägeli, 1849 | subdivision_ranks = Species | subdivision = See text }}
'''''Coelastrum''''' is a genus of green algae in the Scenedesmaceae family. It is a common component of the phytoplankton in freshwater habitats such as ponds, lakes, waterfalls, and temporary pools of water,<ref name=Shubert2014/> particularly eutrophic ones.<ref name=Liang>{{cite journal|doi=10.1016/j.protis.2020.125758 |title=The Draft Genome of ''Coelastrum proboscideum'' (Sphaeropleales, Chlorophyta) |date=2020 |last1=Liang |first1=Hongping |last2=Wang |first2=Hongli |last3=Xu |first3=Yan |last4=Li |first4=Linzhou |last5=Melkonian |first5=Barbara |last6=Lorenz |first6=Maike |last7=Friedl |first7=Thomas |last8=Sahu |first8=Sunil Kumar |last9=Yu |first9=Jin |last10=Liu |first10=Huan |last11=Melkonian |first11=Michael |last12=Wang |first12=Sibo |journal=Protist |volume=171 |issue=5 |pmid=33126018 |s2cid=225359754 |url=https://backend.orbit.dtu.dk/ws/files/255434343/Draft_Genome_Coelastrum_proboscideum_Sunil.pdf }}</ref> The genus has a more or less cosmopolitan distribution,<ref name=Bicudo_and_Menezes2006>{{cite book | title= Gêneros de Algas de Águas Continentais do Brasil: chave para identificação e descrições | edition=2 | year=2006 | first1=Carlos E. M. |last1=Bicudo | first2=Mariângela | last2= Menezes | publisher= RiMa Editora | pages=508 | isbn= 857656064X }}</ref> although some species appear to have more restricted geographical distributions.<ref>{{cite journal|doi=10.2478/s11756-007-0068-6 |title=''Coelastrum pascheri'' sp. n., a new green alga from lakes of the Bohemian Forest |date=2006 |last1=Lukavský |first1=Jaromír |journal=Biologia |volume=61 |pages=S485–S490 |bibcode=2006Biolg..61S.485L |s2cid=29102851 }}</ref> The name comes from the Greek terms ''koilos'', meaning hollow, and ''astron'', meaning star.<ref name=Graham>{{Cite book|last1=Graham|first1=J.E.|last2=Wilcox|first2=L.W.|last3=Graham|first3=L.E.|title=Algae, 2nd Edition|publisher=Pearson|year=2009|isbn=9780321603128|pages=616}}</ref>
==Description== ''Coelastrum'' consists of round colonies of cells (termed coenobia) of 4, 8, 16, 32, or 64 cells. Cells are spherical to polygonal, and are connected to each other via extensions of their cell walls to form hollow spheres. The cells may have various ornamentation such as protuberans, and have one parietal chloroplast with a single pyrenoid.<ref name=Shubert2014>{{cite book |editor-first1=John D.|editor-last1=Wehr|editor-first2=Robert G.|editor-last2=Sheath|editor-first3=J. Patrick|editor-last3=Kociolek |date= 2014 |edition=2 |title= Freshwater Algae of North America: Ecology and Classification |last1= Shubert|first1=Elliot| last2=Gärtner |first2=Georg |chapter= Chapter 7. Nonmotile Coccoid and Colonial Green Algae |url= |location= |publisher= Elsevier Inc. |page= |isbn=978-0-12-385876-4 }}</ref>
''Coelastrum'' reproduces asexually. Prior to reproduction, cell nuclei undergo mitosis, forming multinucleate cells. The cell then undergoes cytokinesis and a new daughter colony is formed within the parental cell.<ref name=AlgaeBase/>
===Identification=== Species of ''Coelastrum'' are distinguished from each other by their morphologies—in particular, their cell size and shape, number of cells per coenobia, and the nature of the ornamentation surrounding the cells and connecting the cells to each other.<ref name=AlgaeBase>{{AlgaeBase genus|id=43467|name=Coelastrum|access-date=2023-11-23}}</ref> However, a great deal of morphological variability exists, which complicates species delimitation and therefore identification.<ref name=Hegewald_2010/>
A similar genus is ''Hariotina'', also part of the subfamily Coelastroideae. ''Hariotina'' can be distinguished by having cells connected by one to three strands at the top (rather than at their base), and by having colonies surrounded by mucilage (while ''Coelastrum'' lacks mucilage).<ref name=Hegewald_2010/>
==Taxonomy== ''Coelastrum'' was once classified as a member of its own family, the Coelastraceae, which has always considered to be similar to the Scenedesmaceae. With molecular phylogenetic analyses, Scenedesmaceae was found to paraphyletic with respect to Coelastraceae and therefore Coelastraceae placed into Scenedesmaceae as its own subfamily, Coelastroideae.<ref name=Hegewald_2010>{{cite journal | doi=10.2216/09-61.1| title=ITS2 sequence-structure phylogeny in the Scenedesmaceae with special reference to ''Coelastrum'' (Chlorophyta, Chlorophyceae), including the new genera ''Comasiella'' and ''Pectinodesmus''| date=2010| last1=Hegewald| first1=Eberhard| last2=Wolf| first2=Matthias| last3=Keller| first3=Alexander| last4=Friedl| first4=Thomas| last5=Krienitz| first5=Lothar| journal=Phycologia| volume=49| issue=4| pages=325–335| bibcode=2010Phyco..49..325H| s2cid=85145401}}</ref>
==Uses== Species of ''Coelastrum'' have been tested for uses in biotechnology, such as lipid or astaxanthin production and wastewater treatment.<ref name=Liang/> In paleoecology, they serve as a marker for eutrophication.<ref name=Liang/>
==Species list== thumb|left|Coenobium of ''Coelastrum'' sp. *''Coelastrum astroideum'' *''Coelastrum cambricum'' *''Coelastrum chodatii'' *''Coelastrum crenatum'' *''Coelastrum giganteum'' *''Coelastrum indicum'' *''Coelastrum irregulare'' *''Coelastrum microporum'' *''Coelastrum morus'' *''Coelastrum naegelii'' *''Coelastrum printzii'' *''Coelastrum probiscideum'' *''Coelastrum pseudomicroporum'' *''Coelastrum pulchellum'' *''Coelastrum pulchrum'' *''Coelastrum reticulatum'' *''Coelastrum schizodermaticum'' *''Coelastrum sphaericum'' *''Coelastrum stuhlmanii'' *''Coelastrum triangulare'' *''Coelastrum verrucosum''
==References== {{Reflist}} * {{cite web | url = http://www.algaebase.org/search/genus/detail/?genus_id=43467 | title = ''Coelastrum'' Genus detail | publisher = AlgaeBase | access-date = 2007-09-19 | author = D. Garbary & A. Comas | date = 2004-08-18}}
{{Taxonbar|from=Q290889}} {{Authority control}}
Category:Sphaeropleales genera Category:Sphaeropleales Category:Freshwater algae