Naked filosea

Amoeboid organisms with fine, thread-like pseudopodia (filopodia).

Contents

Nucleariid
Nuclearia
Vampyrella
Diplophrys



Nucleariids

Nuclearia-like filose amoebae. They have round cell bodies that bear filopodia. The filopodia can be hard to see: click on images for full-size. The cell body of some is covered with a thin layer that may be secretion of mucus. The filopodia move, retract, grow, and are sometimes branched.

This and other Filosea may be confused with Heliozoa. However, the axopods of the heliozoans are more rigid, are not branched, and often have small bead-like extrusomes on them.

Despite being amoeboid in form, they are closer related to animals and fungi than they are to the true amoebae like Amoeba and Chaos.



Nuclearia

Nuclearia have cell bodies bearing filose pseudopodia emerging from all over the cell. Cell bodies are at least 10 µm across.

Some cells are covered in a layer of mucus. In these pictures they appear to be covered in small rod-shaped structures which may be bacteria. We can also see ingested algae in the cytoplasm. The reddish coloration of some of these cells could mean that they are Vampyrella instead; both Nuclearia and Vampyrella belong to the same family.

Here is a video of a Nuclearia in movement, showing how the filopodia take on a wavy or bent appearance when they are retracting back into the cell body. They are otherwise straight.



Vampyrella

Circular to polygonal cell body, amoeboid, distinguished by reddish-orange to pinkish coloration of its granular cytoplasm. Filose pseudopodia emerge all around, and can be quite active. Some were observed to be bent or wavy when retracting. Vampyrella supposedly feeds on green algae. This one was observed among a filamentous green alga, and anchored itself to the filaments with its pseudopodia.



Diplophrys

Small circular cell with a prominent yellow drop (oil?) taking up much of the cytoplasm. This image shows a Diplophrys between two other cells. There are filose pseudopodia radiating from two points: the opposite poles of the cell. The cell is actually covered in a fine test of small scales, but this is only visible in electron microscopy.

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