Synurid

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

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>Template:Citation</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|

Representation of a synurophyte

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Classification

Synurales are divided into three families, each with one genus:<ref name="Jo 2016">Template:Cite Q</ref>

• Family Mallomonadaceae Template:Au
  • Mallomonas Template:Au
• Family Synuraceae Template:Au
  • Synura Template:Au
• Family Neotessellaceae Template:Au
  • Neotessella Template:Au (=Tessella Template:Au)

History

The genus Synura was proposed in 1834 by the German microscopist Christian Gottfried Ehrenberg (1795–1876).<ref>See:

• Template:Cite journal 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: 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>Template:Cite journal</ref><ref>Template:Cite journal</ref>

The Chrysophyceae and Synurophyceae are currently recognized as closely related taxa within the Stramenopiles.<ref name="pmid19282238">Template:Cite journal</ref><ref name="PNG">Template:Cite journal</ref> Present classifications include the synurids as an order (Synurales) within Chrysophyceae.<ref name="MorphoSynurapetersenii"/><ref name="8phyla"/>

External links

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