A couple of notable giants from a sluggish creek.

[apochronaut]

These were found in a fairly fertile sluggish creek crossing a farm. It is being fed a bit from cattle manure. Although the temperature is still quite cold, there is a thick cap of algae and much activity
This is a Lacrymaria about 200 microns long.
The first is 2 are 40X .66 Plan Achro Dark Phase. The other 3 are 40X .70 Plan Fluor Phase but type unknown.
AO 10 microscope. with 18 watt tungsten illumination.

[apochronaut]

This is the other big fish in the little pond. #'s 1 and 2 I first thought a rotifer but is likely an Icthydium at full steam ahead. I was unable to capture a good image of it's lateral feelers, or what appeared to be feelers or bristle sensors extending out from it's head. Visually it looked to have plates or scales around the head protrusion too but I couldn't get a good image of those. The bristles and scales can just barely be seen in the first and second images.
In #'s 3&4 it seems to have found something worth spending some time on, in a clump of algae. It was messing around there for 10 or 15 minutes.

[charlie g]

Elegant and gracefull your first ciliates...and childrens author/illustrator: Dr.Seuss would be inspired by these ciliates. Excellent images of gastrtrich and the rotifer meiofauna in the second panel of your rural water ditch neighbors.

Thanks for posting these encounters, apo. charlie g.

[Javier]

Cool images!

[Bruce Taylor]

Very nice! I especially like the phase images. The long-necked ciliate there is not Lacrymaria but Litonotus cygnus. The mouth is in a slit along the convex side of that blade-like proboscis (whereas Lacrymaria has its cytostome in a ciliated protuberance at the very tip of its "neck").

[apochronaut]

Thanks. I probably haven't seen a Lacrymaria then. I see these swan necked ciliates occasionally in habitats that I would suspect to be fairly nutrified. I didn't know to speciate them by the mouth and it is hard to by proboscis length, since they can stretch them. I tried to catch the mouth in focus in the second Dark Phase image but they thrash around, similarly to the Hollywood depictions of a Brontosaurus.
All of the images are phase, just the objective that produces those lower contrast paler ones has an unusual annulus and I can find out nothing about it.

[Bruce Taylor]

It's easy to get the swan-like ciliates mixed up. Another one to watch for is Amphileptus procerus, which resembles Litonotus cygnus but has multiple contractile vacuoles and a little fan of toxicysts at the tip of the proboscis. And some dileptids (Dileptus in the old sense) can look pretty swan-like. Here's one that has been mislabelled for the past fifteen years: https://beyondthehumaneye.blogspot.com/ ... -swan.html That one is actually in the family Dimacrocaryonidae, order Dileptida (possibly a species of Rimaleptus).

Anyway, if you can't see the mouth clearly, Lacrymaria can usually be spotted by its frantic movements (the neck darts all over, searching for prey) and by a tendency for the body to show spiral ciliation when the cell is contracted. Litonotus and Amphileptus are flat, and move more serenely.

[Michael Müller]

The gastrotrich (pictures 6 & 7) is Lepidodermella squammata. The genus Ichthydium has no scales on the cuticle.
Good photos!

[apochronaut]

Thanks! The scales were very evident, almost reptilian.