Didinium nasutum or Didinium gargantua ?

Franz Neidl · Post by **Franz Neidl** » Mon Jan 02, 2012 6:51 am

I found this ciliate (100µm long) in marine plankton. I am sure that this is a Didinium, but I dont know if it is Didinum nasutum or Didinium gargantua. I am more inclined to D. gargantua.
2 pictures in DIC, Obj. 40x

Franz

Jacek · Post by **Jacek** » Mon Jan 02, 2012 7:22 am

Super pictures, it is hard to grasp Didimium

Bruce Taylor · Post by **Bruce Taylor** » Mon Jan 02, 2012 10:56 am

Wonderful pictures.

I would think it's D. gargantua Meunier, because:

1. It has very prominent nematodesmata.
2. The anterior ciliary fringe is located down on the "shoulders" (in nasutum it is supposed to be a little further forward).
3. It was collected in a marine environment (nasutum is found in brackish conditions, but is mainly a freshwater species).
4. The "snout" is relatively plump.

Franz Neidl · Post by **Franz Neidl** » Sat Jan 07, 2012 6:52 am

Bruce, thank you very much for your precious help. With your detailed reasons you've convinced me.

Franz