Protist Identification Please

[jimmymac2]

Hello everyone,
This is my first post on this forum and I hope I am doing everything right! I bought a microscope last summer and I am still a beginner, and at the moment I would like to identify the freshwater life that I put under the microscope. I have a Brunel light microscope (4x, 10x, 20x and 100x objective lenses) as well as an eyecam which connects to my computer on which I use ToupView.
Last weekend I collected some water from my bird bath and along with lots of Haematococcus pluvialis I found a few protists which I am hoping you can help me with. The second one I thought was a Vorticella but Wim van Egmond suggested Opercularia.
Thank you very much!

[Bruce Taylor]

Hi Jimmy,

The first one is a bdelloid rotifer (not a protist, but a tiny animal).

The second is probably not Opercularia but a species of the closely related genus Epistylis. The first picture shows a distinct peristomial lip, which Opercularia typically lacks.

[jimmymac2]

Thanks very much Bruce.
How difficult would it be to get further?
There's a key to Bdelloidea genera here http://www.microscopy-uk.org.uk/mag/ind ... ifer3.html
but I haven't been very successful.
Is E. plicatilis a possibility for the protist?

[75RR]

This is a link to a visual Rotifer Key which you may find helpful.
If you press the printer image on the top left you can download a pdf.

https://docs.google.com/document/d/1CBn ... edit?pli=1

[jimmymac2]

Thanks very much. I have used the key and Taphrocampa seems to be the best fit?
There are 3 species on the NBN Gateway, which is good. Out of them I think T. selenura is the most likely as the dark eye-spot fits and there aren't the folds across the body of the rotifer as there are in T. annulosa. Have I got the correct genus and do you think I might be right with T. selenura?

[75RR]

It could also be Philodina

Identifying beasties is more of a challenge than many people realize.
Just getting to Genus is on occasion quite an achievement.
Getting to species can sometimes be impossible for an amateur.
That is why you will find many identifications use sp. after the Genus, it means an unspecified species of that genus.

http://atbi.eu/summerschool/files/summe ... llabus.pdf

[jimmymac2]

Hello
I am thinking that Taphrocampa is probably more likely as the front end is more rounded rather than in Philodina where it splits into two.
Do you think a British expert might be able to tell which of the three species it might be?
Thank you very much for your help.

[jimmymac2]

Hello again,
I have looked at more birdbath water this morning and along with what I think is Rotifer vulgaris, I have found the largest rotifer I have ever seen. Could someone please help with the ID?

[actinophrys]

Hi James,
Both your rotifers look to be Bdelloidea, but like 75RR says identifying the different kinds is difficult. It depends on particular features that may not be evident at all times, partly from being subtle and partly because the animals are very contractile.

For instance, Philodina and most others do have heads with two lobes, but usually they are only extended for feeding and swimming. Bdelloids also crawl, and in fact get their name from this distinctive leech-like motion, where they take alternate steps with the head and foot. Then the head lobes are usually contracted, like you see in your pictures, and you might have to follow them around for a while before they open up.

By the way, you don't see this kind of crawling in other rotifers like Taphrocampa, which also tend to have a prominent eye and body ridges. In your first images the black spot looks more like the mastax than an eye. In bdelloids eyespots are typically small, paired, and red. They are on the neck in types like Philodina, Adineta, and so on, and on a contractile proboscis in Rotaria (formerly Rotifer), so finding them helps with at least that type.