Polyarthra vulgaris  or Polyarthra dolichoptera.

I agree with Cacilda Rocha Smaoune

John

It is a rotifer belonging to Polyarthra; the species can not be identified on photomicrographs  because detailed analysis of the external morphology (fins, position of antennae, etc) and the trophi are imperative.

I agree with Willem H. De Smet, but can I have a question? What kind of the freshwater habitat you found it? What about pH? Is it a dam, lake or fishpond?

Thanks, Veronika

Dear Dr.Smaoune Ghiles

Polyarthra vulgaris.Domain: Eukarya

Kingdom: Animalia

Phylum: Rotifera

Class: Monogonata

Order: Ploimida

Family: Synchaetidae

Genus: Polyarthra

Specific epithet: vulgaris

SJ Muhammed

identification to species level impossible

As Dr. Smet said, only Polyarthra, for species identification  need to be dissected.

CL

send a picture of the trophi! then we can try

Polyarthra. For species identification you need to dissected and see the mastax

I agree with Dr. Willem H. De Smet and Dr. Paulina Barbosa. Species identification of genus Polyarthra needs dissection.

Regards

SM Najim

Please, I would like to know how the dissected ?

Do you know this publication?

Koste W. (1978): Rotatoria, Die Rädertiere Mitteleuropas, Ein Bestimmungswerk, begründet von Max Voigt, Überordnung Monogononta. – Gebrüder Borntraeger,

Berlin, Stuttgart, 476 pp.

 no dont have 

It could be helpful this website:

http://rotifera.hausdernatur.at/Species/Index/1710

Very good publication with a guide to identification is:

http://mediacdn.nhbs.com/jackets/jackets_resizer_xlarge/13/133549.jpg

At first you should check the external morphology: body length; fins: how long they are, their shape, present or not the ventral fins (for example in the picture you can see shorter ventral fins: http://rotifera.hausdernatur.at/Rotifer_data/images/addscan/_full-size/Polyarthra%20dolichoptera%20Idelson,%201925%20[Bartos,%201951].jpg

etc.

And finally you can dissolve it by solution of sodium hypochlorite (NaClO). Maybe you could know it like a SAVO for cleaning and disinfection. The rotifer throphi remain and you can check it. The rotifer throphi website for example: http://www.rotifera.hausdernatur.at/Rotifer_data/trophi/

The quality of the image is not good to try the identification.

Marcelo

to see the rotifer throphi you have to dissolve with sodium hypochorite.

a more recent identification guide

Nogrady, T. & Segers, H. (eds.) 2002. Rotifera vol. 6. Asplanchnidae, Gastropodidae, Lindiidae, Microcodidae, Synchaetidae, Trochosphaeridae and Filinia. In: Guides to the Identification of the Microinvertebrates of the Continental Waters of the World, vol. 18. Dumont H. J. (ed.), Backhuys Publishers, Leiden: 1–264.

I agree with Willem H. De Smet 

It is in general not possible to safely identify Polyarthra from a single photograph, it would need different views and ideally also information on the trophi. In this particular case however P. remata is likely. This small species is characteristic by a trilobed posterior body end and only 4 vitellary nuclei (the latter is not entirely clear from your photo, please check). Size should be less than 100 µm and no ventral appendages should be present.