Synurid

The synurids (order Synurales) are a small group of heterokont algae, found mostly in freshwater environments, characterized by cells covered in silica scales.

The cells have two heterokont flagella, inserted parallel to one another at the anterior, whose ultrastructure is a distinguishing characteristic of the group.

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.

[6][7] The Chrysophyceae and Synurophyceae are currently recognized as closely related taxa within the Stramenopiles.

[8][9] Present classifications include the synurids as an order (Synurales) within Chrysophyceae.

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
Representation of a Synurophyte
  1. Flagellum with mastigonemes
  2. Residual flagellum with swelling
  3. Surface scale
  4. Golgi apparatus ; modifies proteins and sends them out of the cell
  5. Plastid membranes (4, secondary red)
  6. Thylakoid , site of the light-dependent reactions of photosynthesis
  7. Nucleus
  8. Endoplasmic reticulum , the transport network for molecules going to specific parts of the cell
  9. Mitochondrion , creates ATP (energy) for the cell, tubular cristae
  10. Lysosome , holds enzymes
  11. Phagocytic vacuole with prey
  12. Bristle
  13. Dome
  14. V-rib
  15. Shield
  16. Hood
  17. Flange