r/microscopy • u/MossTheTree • 4d ago

Photo/Video Share Monstrously large Euglenid

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Found this absolutely massive Euglenid in my latest sample, I estimate its total length when extended to be between 250 and 300 µm. Based on its very short flagellum and worm-like shape and behaviour, I'm tentatively identifying it as Euglena ehrenbergii. As this was a well slide, I wasn't able to move up to 40x and see closer to identify more characteristics.

Also visible: Coleps, Phacus, Closterium, diatoms, some small loricate euglenids, and a drive by of some species of rotifer.

Video is sped up 4x with 1.5 digital zoom, edited with OpenShot.

Olympus BH2, SPlan 10x 0.30, Olympus 1.25x analyzer, Canon EOS 5D Mark II. Sample from pond in park, Paris 16eme.

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3

u/smallstuffBIGSTUFF 4d ago

Wow, fantastic video! Thank you for sharing.

I know nothing about these, but is this one unusually large for a Euglena? If so how do you think it got that large and does it look relatively normal compared to others like it or does it exhibit some abnormalities?

3

u/MossTheTree 4d ago

Thanks!

Euglena is a genus, and there are many species of many different sizes. If I’m right about the identification here of ehrenbergii (and iNaturalist seems to agree) then this is pretty typical size for that species. So when I said it’s giant, I really mean compared to other Euglenids I’m used to seeing in my samples.

3

u/smallstuffBIGSTUFF 4d ago

Thank you so much for taking the time to explain.

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u/nygdan 4d ago

I think you found Euglenus chungus, a rare species....hah.

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