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Part of cytoplasm extends from the body

After being collected from a paddy field, the sample was put on 1% agar plate with a drop of distilled water and kept for a few days.

Helizoa are usually round, but this one extends part of its cytoplasm outward. After a while it pulls the cytoplasm back inside the body again.

Commentary by Prof. Yuji Tsukii, Hosei University
Small types of Helizoa like this one can be frequently observed, but they do not have any remarkable features. Furthermore, there is very little information in the literature on protozoa, so it can be difficult to identify these organisms.

The only notable features of the organism in this video are the long, needle-like axopods extending from the cell surface. It probably belongs to the genus Rabdiophrys, but this group no longer belongs to the Helizoea group. It is now classified as part of the Filosea group, not Heliozoea.

This video shows part of the cytoplasm extending from the spherical body so that it appears somewhat like an amoeba. Helizoa may exhibit this hunting behavior to catch larger prey, distorting its normally spherical shape into a shape more like that of an amoeba.

Sampling Date : 16 October 2006

Sampling Site : KASHIMADAI paddy field  Google Map

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