Large ciliate for Id please

[jc maccagno]

slow running freshwater creek 40X

[Charles Krebs]

Makes me think of Trachelius, but I see no sign of the long "snout".

[Bruce Taylor]

Like Charles, I was struck by the resemblance to Trachelius ovum.

There is a highly vacuolated ciliate called Holophrya vesiculosa. It has a prominent cytopharyngeal basket, like this fellow. According to Kahl, it specializes in eating Synura (I see spherical colonial algae in these pics, but can't tell if they're Synura).

The size is off, though...Holophrya vesiculosa should be half as big. On the other hand, size is a weak identifying trait, especially in seldom-described ciliates.

On the other other hand , H. vesiculosa should be surrounded by mucocysts, which I can't say I see, here...so, maybe a damaged Trachelius, after all?

[jc maccagno]

Thank you both for your suggestions..haven't seen this one since

John