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Flagellate

Posted: Wed Jul 01, 2020 6:48 am
by janvangastel
I found a relatively large flagellate in a pond sample. No clue about the name:

Re: Flagellate

Posted: Wed Jul 01, 2020 8:43 am
by MicroBob
Hi Jan,
I can't watch the video due to mobile internet limits but I can recommend a suitable identification book. Since you are from the Netherlands you can probably read german to som degree? Here in Germany we use "Das Leben im Wassertropfen" as an amateur fresh water ID book. An older issue will do.

Bob

Re: Flagellate

Posted: Wed Jul 01, 2020 11:17 am
by janvangastel
Thanks for the tip Bob. Looks like a very nice book. I have ordered it.

Re: Flagellate

Posted: Wed Jul 01, 2020 12:55 pm
by 75RR
Great catch and video. looks like it might be a Peranema sp.

Re: Flagellate

Posted: Wed Jul 01, 2020 2:40 pm
by Bruce Taylor
75RR wrote:
Wed Jul 01, 2020 12:55 pm
Great catch and video. looks like it might be a Peranema sp.
Peranemids are "anterior gliders," which means they have a long, thick anterior flagellum, used for "gliding motility" (forward motion is produced on the surface of the flagellum, without the need for any movement). The single emergent flagellum we see here is short, fine, and moving very energetically. We don't see gliding motility. The cell is very metabolic (showing euglenoid movement), and non-photosynthetic (a heterotroph). It seems to lack an eyespot. So: Astasia seems likely. Some traditional Astasia species have been moved to Euglena and similar euglenoids are often placed in Khawkinea, but I think the lack of an eyespot rules those out. However, I'm not particularly sharp at euglenoid identification. :)

Re: Flagellate

Posted: Wed Jul 01, 2020 2:57 pm
by 75RR
Bruce Taylor wrote:
Wed Jul 01, 2020 2:40 pm
75RR wrote:
Wed Jul 01, 2020 12:55 pm
Great catch and video. looks like it might be a Peranema sp.
Peranemids are "anterior gliders," which means they have a long, thick anterior flagellum, used for "gliding motility" (forward motion is produced on the surface of the flagellum, without the need for any movement). The single emergent flagellum we see here is short, fine, and moving very energetically. We don't see gliding motility. The cell is very metabolic (showing euglenoid movement), and non-photosynthetic (a heterotroph). It seems to lack an eyespot. So: Astasia seems likely. Some traditional Astasia species have been moved to Euglena and similar euglenoids are often placed in Khawkinea, but I think the lack of an eyespot rules those out. However, I'm not particularly sharp at euglenoid identification. :)
See what you mean about the flagellum, does seem a little short and overly energetic :)

I think this drawing shows the difference clearly
.
Image

Re: Flagellate

Posted: Wed Jul 01, 2020 5:00 pm
by Bruce Taylor
75RR wrote:
Wed Jul 01, 2020 2:57 pm
See what you mean about the flagellum, does seem a little short and overly energetic :)

I think this drawing shows the difference clearly
.
Yes, in locomotion peranemids hold the flagellum stiffly forward, as shown in your image. The bent tip beats and twitches, but doesn't really contribute to forward movement (if it is chemically immobilized, the cell can still glide forward). When a peranemid is squirming in place, the flagellum relaxes and may thrash about, but it is fairly thick and the movements are somewhat languid.

A peranemid would also have an ingestion apparatus in the form of 2 stiff rods near the base of the flagellum. This critter seems to lack an ingestion device.