An amoeba with a strange shape

This small amoeba is deeply dented on one side of the body, and there are pseudopodia-like structures all over the surface. The first part of the video was taken in real time, so the amoeba appears nearly motionless. However, in the time-lapse segment, we can see the amoeba moving slowly, with the particles in its cytoplasm moving as well.

Commentary by Prof. Yuji Tsukii, Hosei University
It is difficult to say what type of amoeba this is. It might belong to Heliozoa as the cell shape does not change. However, some smaller Heliozoa with very thin pseudopodia have recently been reclassified from the Heliozoa group to the Filosea group, including Rabdiophrys and Pompholyxophrys. As the organism in this video appears to have very thin pseudopodia, it might be Rabdiophrys belonging to Filosea. Small Heliozoa(and other small amoebae) are often found in the field, but to what group these organisms should be classified can be perplexing.

http://protist.i.hosei.ac.jp/PDB/Im.....

http://protist.i.hosei.ac.jp/PDB/Im.....

Sampling Date : 28 May 2009

Sampling Site : Hirose River B  Google Map