A ciliate resembling a plesiosaur

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.

A slender ciliate covered by long thin cilia repeatedly moves back and forth. Is this behavior a method of seeking food?

Commentary by Prof. Yuji Tsukii, Hosei University
This ciliate is Stichotricha in the group of Stichotrichida.

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

The long oval body is tapered at the ends, and there are rows of long cilia covering the extended “nose” from the front to the cytostome (mouth) located in the body. Cirri form spiral rows on the body.

This ciliate has secreted a gel-like substance that formed a cylindrical structure called a lorica, and its whole body is moving back and forth inside the lorica, though it is not shown in this video, it is shown in the above link. Symbiotic algae are sometimes found inside Stichotricha cells, but we cannot see any algae in this video. The organism in this video appears to be Stichotricha secunda, but its cell length is nearly 300μm, which is longer than the usual 130-200μm of S.secunda. Therefore it might be a larger type of S.secunda, or possibly another species.

Sampling Date : 16 October 2006

Sampling Site : KASHIMADAI paddy field  Google Map