Freshwater ciliate ID

[Wes]

I found this organism in a pond water culture that had a lot of crustaceans and insect larvae (it was lightly capped and when I opened it a wimpy mosquito tried to escape). The organism measures 40 x 110 µm in size. The images are of the same animal (different z-planes) and are original size, just cropped so you can zoom in by opening in a new tab (there are some kind of ciliary rows).

Any clue what this guy is?





Wes

[Bruce Taylor]

It seems to be a species of Metopus, with the cell slightly rotated, so that we only see the posterior end of the adoral zone of membranelles. Note the concentration of refractile granules in the anterior of the cell, and the large vacuole and long cilia at the posterior.

[Wes]

You are a protist wizard Bruce! Many thanks for the identification. I read that this is an anaerobic organism and I managed to find it inside a decaying maize kernel in the bottom of the culture where I'd expect poor oxygen conditions.

Regards
Wes