Synurid

{{Short description|Group of algae}} {{Automatic taxobox | name = Synurids | image = Synura.jpg | image_caption = A colony of ''Synura'' sp. | taxon = Synurales | authority = Andersen, 1987 | subdivision_ranks = Genera | subdivision_ref = <ref name="Developmentsinthesilica"/> | subdivision = *''Mallomonas'' *''Synura'' *''Tessellaria'' }}

The '''synurids''' (order '''Synurales''') are a small group of heterokont algae, found mostly in freshwater environments, characterized by cells covered in silica scales.<ref name="MorphoSynurapetersenii"/>

==Characteristics== [[File:Synura_petersenii.png|thumb|right|upright|alt=High magnification SEM image of a single Synura cell: It is covered with about 50 delicate, oval scales.|A single cell of the freshwater algae species ''Synura petersenii'', false color image created using SEM]] They are covered in silicate scales and spines. In ''Synura'', these are formed on the surface of the chloroplasts,<ref>{{citation |author=Barry S.C. Leadbeater |year=1990 |title=Ultrastructure and assembly of the scale case in ''Synura'' (Synurophyceae Andersen) |journal=British Phycological Journal |volume=25 |issue=2 |pages=117–132 |doi=10.1080/00071619000650111|doi-access=free }}</ref> two of which are usually present, but sometimes only one divided into two lobes is seen. The cells have two heterokont flagella, inserted parallel to one another at the anterior, whose ultrastructure is a distinguishing characteristic of the group. Both asexual and isogamous sexual reproduction occur.

==Morphology== [[File:2023 Synurophyte.svg|center|thumb|upright=2|{{center|'''Representation of a synurophyte'''}}{{ordered list|Flagellum with mastigonemes| Residual flagellum with swelling| Surface scale| Golgi apparatus; modifies proteins and sends them out of the cell| Plastid membranes (4, secondary red)| Thylakoid, site of the light-dependent reactions of photosynthesis| Nucleus| Endoplasmic reticulum, the transport network for molecules going to specific parts of the cell| Mitochondrion, creates ATP (energy) for the cell, tubular cristae| Lysosome, holds enzymes| Phagocytic vacuole with prey| Bristle| Dome| V-rib| Shield| Hood| Flange|}}]]

==Classification== Synurales are divided into three families, each with one genus:<ref name="Jo 2016">{{cite Q|Q99647124}}</ref> * Family Mallomonadaceae {{au|Diesing, 1866}} ** ''Mallomonas'' {{au|Perty, 1852}} * Family Synuraceae {{au|Lemmermann, 1899 emend. B.Y. Jo, J.I. Kim, W. Shin, P.Škaloud & P. Siver, 2016}} ** ''Synura'' {{au|Ehrenberg, 1834}} * Family Neotessellaceae {{au|B.Y. Jo, J.I. Kim, W. Shin, P.Škaloud & P. Siver, 2016}} ** ''Neotessella'' {{au|B.Y. Jo, J.I. Kim, W. Shin, P.Škaloud & P. Siver, 2016}} (=''Tessella'' {{au|Playfair, 1915 ''nom. illeg.''}})

==History== The genus ''Synura'' was proposed in 1834 by the German microscopist Christian Gottfried Ehrenberg (1795–1876).<ref>See: * {{cite journal |last1=Ehrenberg |title=Dritter Beitrag zur Erkenntniss grosser Organisation in der Richtung des kleinsten Raumes |journal=Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin [Treatises of the Royal Academy of Sciences in Berlin] |date=1833 |volume=1833 |pages=145–336 |trans-title=Third contribution to [our] knowledge of greater organization in the direction of the smallest realm |language=de |url=https://www.biodiversitylibrary.org/item/93805#page/181/mode/1up }} [https://www.biodiversitylibrary.org/item/93805#page/317/mode/1up From p. 281:] Ehrenberg created a new family, ''Volvocina'', ''" ... wozu ich die vier neuen Gattungen ''Chlamidomonas'', ''Syncrypta'', ''Synura'', und ''Uroglena'' stelle."'' ( ... into which I place the four new genera ''Chlamidomonas'', ''Syncrypta'', ''Synura'', and ''Uroglena''.) [Note: According to p. 145, Ehrenberg's paper was first presented in 1832, revised somewhat, and published in 1834.] * See also: [http://www.algaebase.org/search/genus/detail/?genus_id=43807 AlgaeBase: ''Synura'' Ehrenberg, 1834]</ref>

The synurids were originally included among the golden algae in the order Ochromonadales as the family Mallomonadaceae or as the family Synuraceae . They were formally defined as a separate group by Andersen in 1987, who placed them in their own class '''Synurophyceae''', based on an earlier approach of more narrowly defining major lineages of chrysophyte algae by British phycologist David Hibberd.<ref>{{cite journal|doi=10.1111/j.1095-8339.1976.tb01352.x|title=The ultrastructure and taxonomy of the Chrysophyceae and Prymnesiophyceae (Haptophyceae): A survey with some new observations on the ultrastructure of the Chrysophyceae|year=1976|last1=Hibberd|first1=D. J.|journal=Botanical Journal of the Linnean Society|volume=72|issue=2|pages=55–80}}</ref><ref>{{cite journal|doi=10.1016/0303-2647(79)90025-X|title=The structure and phylogenetic significance of the flagellar transition region in the chlorophyll c-containing algae|year=1979|last1=Hibberd|first1=David J.|journal=Biosystems|volume=11|issue=4|pages=243–261|pmid=396946|bibcode=1979BiSys..11..243H }}</ref>

The Chrysophyceae and Synurophyceae are currently recognized as closely related taxa within the Stramenopiles.<ref name="pmid19282238">{{cite journal |vauthors=Grant J, Tekle YI, Anderson OR, Patterson DJ, Katz LA |title=Multigene Evidence for the Placement of a Heterotrophic Amoeboid Lineage Leukarachnion sp. among Photosynthetic Stramenopiles |journal=Protist |volume= 160|issue= 3|pages= 376–85 |date=March 2009 |pmid=19282238 |doi=10.1016/j.protis.2009.01.001 }}</ref><ref name="PNG">{{cite journal |author=W. Vyverman |author2=G. Cronberg |title=Scale bearing chrysophytes from Papua New Guinea |journal=Nordic Journal of Botany |volume= 13|issue= 1|pages= 111–20 |date=March 1993 |doi=10.1111/j.1756-1051.1993.tb00022.x }}</ref> Present classifications include the synurids as an order (Synurales) within Chrysophyceae.<ref name="MorphoSynurapetersenii"/><ref name="8phyla"/>

==References== {{Reflist|refs=

<ref name="MorphoSynurapetersenii">{{cite journal|title=Morphological delineation and distribution patterns of four newly described species within the Synura petersenii species complex (Chrysophyceae, Stramenopiles)|vauthors=Škaloud P, Škaloudová M, Procházková A, Němcová Y|doi=10.1080/09670262.2014.905710|date=2014|volume=49|issue=2|journal=European Journal of Phycology|pages=213–229|doi-access=free|bibcode=2014EJPhy..49..213S }}</ref>

<ref name="8phyla">{{cite journal|title=Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences|first1=Thomas|last1=Cavalier-Smith|date=2017|journal=Protoplasma|pages=297–357|volume=255|issue=1 |doi=10.1007/s00709-017-1147-3|pmid=28875267 |pmc=5756292 }}</ref>

<ref name="Developmentsinthesilica">{{cite journal|title=Developments in the taxonomy of silica-scaled chrysophytes – from morphological and ultrastructural to molecular approaches|first1=Pavel|last1=Škaloud|first2=Jørgen|last2=Kristiansen|first3=Magda|last3=Škaloudová|journal=Nordic Journal of Botany|volume=31|issue=4|date=July 2013|publication-date=August 2013|pages=385–402|doi=10.1111/j.1756-1051.2013.00119.x}}</ref>

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==External links== {{Commons category}}

Category:Chrysophyceae