Testate Amoeba

[btschumy]

This past week my pond aquarium has exploded with testate amoebae. They have multiple spikes emanating from the test leading me to think this might be Centropyxis (although the one in the picture doesn't have spikes visible. There were several pseudopods sticking out. This image shows many more due to the stacking.

Stack of 9 images through 10x objective.

Testate Amoeba.jpg (25.3 KiB) Viewed 5282 times

[Mintaka]

Beautiful 3d-like pic.

[JimT]

Very nice. Great to find these when they have pseudopods sticking out.

[KurtM]

I have had population explosions like that in my micro-aquariums. Pretty cool to know all those wee specks you can see with good light and clean readers are really testate amoebas.

[actinophrys]

This is an interesting amoeba. Are you sure it was the same as the ones with spines, and if so where would they be? The round shape and lobed collar look typical of some genera like Netzelia rather than Centropyxis, but those wouldn't have any.

(In case it might help, there are nice descriptions of most kinds at Siemensma's world of amoeboid organisms.)

[btschumy]

Pretty sure it is the same on as what I saw with spines. Here is one where a spine is visible.

[btschumy]

After further examination, I think actinophrys is correct that there are two different species of testate amoeba in my tank. The first picture with no visible spines is different from the other with spines (which I think is Centropyxis). I got another nice image of the latter.

[Johann]

Very nice

[actinophrys]

Thanks for the additional images, Bill. The first of the two doesn't have a collar like the one you started with, but it still has a terminal opening, and both look globular in shape. This is different from Centropyxis shells, which are flattened with a round opening on the underside (and typically clear enough that you can see it from above or below).

I think these two are both Difflugia, taken in a broad sense. It's been proposed the multi-spined species D. corona and D. tuberspinifera should be classified separately as Mediolus, and I'd expect more such divisions are to come, since they form at least two separate groups on genetic trees.

[cuxlander]

Hello btschumi,
The third one is definitely Difflugia corona.
The collar of the other two look more like Difflugia lithoplites.
Ferry Siemensma writes in his arcella.nl : "not seldom together with Difflugia corona and Difflugia capreolata."
How big were your specimen?
Greetings,
Hans


PS Interesting, the last one has a "Shell with tubercular structure" as Siemensma writes under his last D. corona.

[gekko]

Very nice images.