Video ID for a variety of critters

[xioz]

Hi all,
Working on a video, I like to try and get some labels on the critters we see and learn about them, even if the labels are general ones.
I had a go myself in identifying some, see text below, am I in the ballpark? They should be fairly common as they are from my fish tank.



1) Oblong Ciliate: Hypotrich? Holosticha pullaster?
2) Looks like a micro crustacean with a shell but I think it might be a ciliate with cirri side on. Euplotes Patella?
3) 2 or 3 red spot Ciliate
4) A Gastrotrich & another Holosticha pullaster? Side on again, it looks like it is crawling on 'legs'
5) A round Ciliate with cirri? (Hypotrichia?) Euplotes ?
6) The long slow moving one is algae I think but what sort? Still getting used to the idea of 'plants' moving!

Thanks for any suggestions!

Regards,
Malcolm

[xioz]

Just realised that number 6 is a Cyanobacteria from one of Microcomos's videos, the other two in shot would be chambered algae. I didn't think they got that large!
And they slide using slime, amazing.

[Bruce Taylor]

1. Yes, Holosticha pullaster (it has trailing transverse cirri, contractile vacuole in posterior third of the cell). The only member of the genus found in freshwater.

2. Aspidisca cicada (adoral membranelles are not visible; dorsal surface is deeply ridged).

3. A ciliate in the family Chilodonellidae (ID to genus would require a closer view of the somatic ciliature).

4. Gastrotrich below, with a hypotrich ciliate above (probably H. pullaster again)

5. A sick or damaged ciliate, probably a halteriid (Halteria etc.). It has adoral membranelles, and seems to have equatorial "jumping bristles."

6, yes, a cyanobacterium. Oscillatoria, I think (but I usually ignore critters that photosynthesize ).

[xioz]

Thank you Bruce, time for me to do some more reading about these subjects!
I actually did see some of these names like "Aspidisca" when doing more looking, but without better footage and experience it is hard to see and learn the identifying features. Fantastic we can benefit from your experience and start learning ourselves.

Number 5: Halteriid had wonderful 3D structure with the groups of bristles around the body. I saw jumping bristles mentioned, but there was no 'distinctive movement' ie jumping, so I will have to look for the adoral membranelles.

How do you tell if a ciliate is sick/damaged, is it mainly experience with it's normal mode of movement and appearance, or just generally slow / spinning is a good clue?

Regards,
Malcolm

[Bruce Taylor]

How do you tell if a ciliate is sick/damaged, is it mainly experience with it's normal mode of movement and appearance, or just generally slow / spinning is a good clue?

In this case, it has a full AZM (adoral zone of membranelles), but the membranelles themselves are mostly immobile. In a healthy spirotrich cell, these would be active. The slow spinning is also a clue, here. Healthy cells usually move purposefully.