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There seems to be some uncertainty identifying Difflugia pyriformis but its the closest match I could find. Input welcome.

nice video Chris-- Thanks for sharing . I've been seeing a lot of testate amoebas lately, but they have been pretty motionless. Nice to see one waling around !

Hello Chris,
Scale bar 100 µm?
may be Zivkovicia spectabilis, look at 40-45 seconds for view into pseudostome.
compare https://www.arcella.nl/zivkovicia-spectabilis/
Cheers,
Hans

Cheers mintakax. Yes I was lucky to find an occupied one. In all honesty, if it wasn't moving I'd likely have dismissed it as a clump of detritus and moved on.

Thanks for the input cuxlander. The overlay scale was made using a calibration slide so should be accurate. I studied the footage further and I can't personally make out a bridge structure, I didn't focus deeply enough into the neck to get a clear view sadly. There seems to be a lot of conflicting information surrounding this form of test, which is understandable when you look at the form variation present for assumed pyriformis alone: https://www.arcella.nl/difflugia-pyriformis-group/ and more variation if you look at the images for both species in this document: https://ab.pensoft.net/book/38685/

As a hobbyist without DNA analysis available its a tough call. What I have learned though is awe for the sheer variety of amoebas and their adaptation.

Hello Chris,

your specimen is about 120 µm high. Most pyriform difflugia are much bigger.
One characteristic is the very regular bunch of "stones" around the aperture. Not typical for Zivkovicia/pontigulasia/, my first wild guess was probably wrong.

As Ferry Siemensma wrote, "Identification [of Difflugiidae] at species level is for most species extremely difficult."

Anyway, a beautiful video!
Cheers,
Hans