Thesynurids (orderSynurales) are a small group ofheterokont algae, found mostly infreshwater environments, characterized by cells covered insilica scales.[2]
A single cell of the freshwater algae speciesSynura petersenii, false color image created usingSEM
They are covered in silicate scales and spines. InSynura, these are formed on the surface of thechloroplasts,[3] two of which are usually present, but sometimes only one divided into two lobes is seen. The cells have two heterokontflagella, inserted parallel to one another at the anterior, whose ultrastructure is a distinguishing characteristic of the group. Both asexual andisogamous sexual reproduction occur.
The synurids were originally included among thegolden algae in the orderOchromonadales 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 classSynurophyceae, based on an earlier approach of more narrowly defining major lineages of chrysophyte algae by British phycologist David Hibberd.[6][7]
TheChrysophyceae and Synurophyceae are currently recognized as closely related taxa within theStramenopiles.[8][9] Present classifications include the synurids as an order (Synurales) withinChrysophyceae.[2][10]
^Škaloud, Pavel; Kristiansen, Jørgen; Škaloudová, Magda (July 2013). "Developments in the taxonomy of silica-scaled chrysophytes – from morphological and ultrastructural to molecular approaches".Nordic Journal of Botany.31 (4) (published August 2013):385–402.doi:10.1111/j.1756-1051.2013.00119.x.
^Barry S.C. Leadbeater (1990), "Ultrastructure and assembly of the scale case inSynura (Synurophyceae Andersen)",British Phycological Journal,25 (2):117–132,doi:10.1080/00071619000650111
Ehrenberg (1833)."Dritter Beitrag zur Erkenntniss grosser Organisation in der Richtung des kleinsten Raumes" [Third contribution to [our] knowledge of greater organization in the direction of the smallest realm].Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin [Treatises of the Royal Academy of Sciences in Berlin] (in German).1833:145–336.From p. 281: Ehrenberg created a new family,Volvocina," ... wozu ich die vier neuen GattungenChlamidomonas,Syncrypta,Synura, undUroglena stelle." ( ... into which I place the four new generaChlamidomonas,Syncrypta,Synura, andUroglena.) [Note: According to p. 145, Ehrenberg's paper was first presented in 1832, revised somewhat, and published in 1834.]
^Hibberd, D. J. (1976). "The ultrastructure and taxonomy of the Chrysophyceae and Prymnesiophyceae (Haptophyceae): A survey with some new observations on the ultrastructure of the Chrysophyceae".Botanical Journal of the Linnean Society.72 (2):55–80.doi:10.1111/j.1095-8339.1976.tb01352.x.
^Grant J, Tekle YI, Anderson OR, Patterson DJ, Katz LA (March 2009). "Multigene Evidence for the Placement of a Heterotrophic Amoeboid Lineage Leukarachnion sp. among Photosynthetic Stramenopiles".Protist.160 (3):376–85.doi:10.1016/j.protis.2009.01.001.PMID19282238.
