A ciliate looking for food
After being collected from a paddy field, the sample was put on 1% agar plate with a drop of distilled water and kept for four days. A ciliate quickly darts around. It seems to be looking for food.
Commentary by Prof. Yuji Tsukii, Hosei University
This ciliate may be either Oxytricha or Amphisiella.
It also looks similar to Stylonychia, which has long caudal cirri at the rear end. However, Stylonychia has only three cirri that are symmetrically arranged, whereas this organism has more than three caudal cirri arranged asymmetrically. Moreover, these cirri are of various lengths, which make it appear like Amphisiella.
However this ciliate has a round cell in contrast to the slender cell of Amphisiella, so this organism is more likely Oxytricha. Oxytricha typically has shorter caudal cirri than Amphisiella, but some species such as Oxytricha lanceolata have relatively long cirri. When it turns, the body of this organism bends slightly to the left or right, which is a characteristic of Oxytricha and Amphisiella. On the other hand, when Stylonychia turns, its body does not bend at all (which means this organism is unlikely to be Stylonychia).
From the shape of the body and characteristics of the cirri, this organism is most likely Oxytricha lanceolata. However, the family Oxytrichidae includes many other species, so it is possible that the organism is neither Amphisiella nor Oxytricha.
For accurate identification, it is necessary to culture this ciliate and fix and stain it by a special method to examine the length and arrangement of its cirri.
Sampling Date : 17 November 2006
Sampling Site : KASHIMADAI paddy field Google Map