''Discoplastis'' is a genus of euglenoid

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

belonging to the family Phacaceae. The species of this genus are found in Europe, Northern America, Southeastern Asia and Australia. ''Discoplastis'' consists of solitary, free-living cells with one emergent

flagellum A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

. The cells have a flexible, spirally striated pellicle and are therefore capable of

metaboly Spirocuta () is a clade of euglenids, single-celled eukaryotes or protists belonging to the phylum Euglenozoa. They are distinguished from other euglenids by active deformation of their cell shape, a process called euglenid motion or metaboly. Thi ...

. When swimming, the cells are a variety of different but characteristic shapes (cylindrical, fusiform, hourglass-shaped, etc.). The posterior of the cell ends in a pointed, colorless cell. Within each cell there are numerous small, discoid

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

lacking

pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...

s. Cells have paramylon grains; the paramylon grains may be monomorphic (all small) or dimorphic (some large, some small). As with other euglenoids, the cell has a reddish eyespot (stigma). ''Discoplastis'' can be distinguished by to the combination of small, discoid parietal chloroplasts without pyrenoids (a

synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel Phenotypic trait, character or character state that has evolution, evolved from its ancestral form (or Plesiomorphy and symplesiomorphy, plesiomorphy). A synapomorphy is an apomorphy sh ...

for the family Phacaceae), and its flexibility. The similar genus '' Flexiglena'' is even more flexible, displaying metabolic movement even when swimming. It is also distinguished by having a large paramylon grain directly adjacent to the stigma.

Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

s suggest the following relationships between species:

References

Euglenozoa genera {{alga-stub