a member of the Noctilucales (Dinophyceae)

Franz Neidl · Post by **Franz Neidl** » Wed Dec 12, 2012 2:39 pm

Yesterday I found a very interesting protist (diameter about 250 µm) in marine plankton . First I thought it was a small Medusa because it was moving like a medusa! Than I saw a nucleus. But in a Medusa you can never have a central nucleus. Conclusion (of a longer investigation): it is a member of the Dinophycea from the Noctilucales. The hole cell was contracting rhythmically, fast and with a great force. I have never seen a protozoon moving like a Medusa! Really impressing..
My question: Could it be Leptodiscus medusoides?

Two pictures with Objective 20Ph and Obj. 20DIC

Franz

Ecki · Post by **Ecki** » Thu Dec 13, 2012 10:37 am

Franz,

I can not help with the ID as marine plankton is a white spot for me. But I always enjoy the peeks into marine protists that you show here. Thank you very much.

Most interesting species!

regards
Ecki

BJ · Post by BJ » Sat Dec 15, 2012 5:47 am

hello Franz,

another very very strange and marvellous beast - thank you !

I have never seen this organism, but I have done a little research and I think that I may have an ID for you.

First I think that you are either correct ( = Leptodiscus medusoides) or very close. I have another possibility for you to consider -perhaps Craspedotella pileolus. This species is about the size of your specimen and has prominent radial structures. From my reading, Leptodiscus is usually much bigger.

The original description of Craspedotella (Kofoid 1905) is available for download here:

http://ia700309.us.archive.org/14/items ... 46harv.pdf

it is at page 241 of a 410 page download

A more recent paper and description is by Gomez, who seems to be the modern "weird and wonderful dinoflagellate" expert:

http://www.scielo.cl/pdf/revbiolmar/v42n1/art10.pdf

the article is in spanish.

See what you think...perhaps your ID of Leptodiscus is still best.

..what strange delight will you have for us next ? !

with my best wishes
Brian