An organism in a group of Rotifera

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. The organism repeatedly expands and contracts its body in a narrow space surrounded by soil aggregates, seeming to look for a food.

Commentary by Prof. Yuji Tsukii, Hosei University
Because the Rotifera group has many species with similar shapes, it is difficult to say even to what genus this organism belongs. The round top (front) is divided by a slant line. Two toes are at the posterior end.

In the group Rotifera, the family Proales and the family Cephalodella (including Notommata, Pleurotrocha, Eosphora, Restiula, Cephalodella, etc.) have similar characteristics.

The organism in this video is most likely Proales, which is shown in the following link.

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

However, the toes of this organism seem to be longer than those of Proales, and hence it could be Cephalodella. Unfortunately I do not have any examples of similar types of Cephalodella in my photo collection.

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

Sampling Date : 16 October 2006

Sampling Site : KASHIMADAI paddy field  Google Map