MicrobeHunter.com Microscopy Forum

I found this in a sample of rainwater and debris from my roof gutter.
At first I thought "another vorticella" but made a short recording of it because of its interesting mouth(?) movement and, focusing high and low, I could not find any stalk, so thought it might be a free-swimming stage.

Since then I have had a look in "Free-Living Freshwater Protozoa." Patterson and found Rhabdostyla to be a possibility.
[ Some sites say Rhabidostyla can be similar to Orborhabdostyla, Apiosoma, Scyphidia, but I get a bit lost ! ]

I cant decide if the mouth(?) is on the upper surface or am I looking through the top surface into the inside ?

Quote, Patterson:-
*120
A Species wilhout a lorica, they attach to the substrate by a stalk. ---- GOT0 121
B Species with a lorica, and/or species wlthout a stalk. ----- GOT0126

*126
A Without a lorica. The cell attaches directly to the substrate with its narrowed posterior end. There is no stalk or the stalk is indistinct. Cells 20-100um long. Fig . 237 ---- RHABDOSTYLA

*125
A With a contractile stalk. Length of cell varies from species to species; most are between 20 and
200um, most commonly 40-80um Figs 232-236 VORTICELLA

60x achromat to Canon aps-c

Rhabdostyla resembles a short-stalked Epistylis. It is attached to the substrate by a short stalk and has a zooid with a peristomial lip (the same goes for Orborhabdostyla, which differs in having a discoidal macronucleus. Scyphidia and Apiosoma are attached directly to the substrate by a "scopula" (an attachment organelle on the bottom of the cell). We don't really see how this peritrich is (or was) attached to the substrate. We don't see a stalk, but we also don't see a scopular attachment point. My suspicion (based on the overall appearance of the cell) is that this is a stalked peritrich, but this individual has been dislodged from its stalk. Since we don't have information about its normal method of attachment, we can't identify it below order Sessilida.

Bruce Taylor wrote: ↑

Wed Dec 08, 2021 5:56 pm

Sessilida.

Thanks Bruce for the interesting, great, info and for your time,
very much appreciated by this beginner !