Giant ciliate expands and contracts

The movement of this large dark-brown ciliate is strange. Standing near a particle, it alternately extends and contracts its body, reaching a length of 300 microns when fully extended, and shrinking to a round body of 200 microns in diameter. Its mouth is sometimes flat, and sometimes looks like a bottle neck.

Commentary by Prof. Yuji Tsukii, Hosei University
This Spathidium syrtis appears quite full after eating a large meal. A feature of this group is its partially flat top. Among the many species in the genus Spathidium, S. syrtis is characterized by its overall large body size.

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

Sampling Date : 27 May 2009

Sampling Site : Hirose River A  Google Map