Episcleria
| Episcleria | |
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| Classification | |
|---|---|
| Eudiktya | |
| Episcleria | |
| Distribution | |
| Miavegr | |
| Number of species | |
Episclera are one of the main clades of Eudiktya on Miavegr, complex multicellular lifeforms evolved inside multiple branches of this group. These organisms are characterized by their internal calcium-carbonate cell-wall.
Evolution
Around 1 Ga BP an Eudiktyan cell absorbed a Lithochroma one, this endosymbiosis produced the Calcoplast organelle of the Episcleria. Thus the descendants of these cells acquired the capability to fixate calcium carbonate and to do photosynthesis (lost in most extant Episcleria). They then rapidly radiated and gave rise to multiple clades of single and multicellular organisms.
Physiology
Episcleria have some differences from the ancestral eudiktyan physiology and organelles. Some of these characteristics are common to all Episclerians.
Calcoplast
The Calcoplast is derived from an endosymbiotic Lithochroma. It keeps a reduced CPPM and part of its cellular machinery. It is often located inside the carbonate cell wall. Its function is to produce this cell wall. In some clades it also kept a photosynthetic function.
Carbonate cell wall
This cell wall is contained inside the cell membrane. It's often highly porous and large holes let the cytoplasm flow on both sides. It sometime can be secreted outside the cell.
Apex/adhesive complex
The apex is part of the cell wall that \extrudes in the front of the cell, while the adhesive complexes are modified cilia, that can strongly latch on surfaces. The combination of these two structures allow Episclarian cells to attach themselves. This structure followed further evolution in different clades. It is of prime importance for sessile and parasitic episclerians.
Photoreceptive pigments
All Episclerians possess photoreceptive pigments and are capable of using them to move towards and away from the light. These are often produced only on one side of the cell (the front) in unicellulars.
Flagella
Flagella are advanced motile complexes made of a rotating protein rotor and a carbonated stator fixed to the cell wall. They allow fast movement in unicellulars.
Phylogeny
| Episcleria |
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