Page 1 of 1
Stentor roeselii? Stentor muelleri?
Posted: Sat May 14, 2022 3:33 pm
by woyjwjl
Do you need to count hairs and determine gene sequences to determine the species?
Re: Stentor roeselii? Stentor muelleri?
Posted: Mon May 16, 2022 10:35 pm
by Bruce Taylor
You don't have to count hairs, but you do have to see the macronucleus.
It is visible in the last image, though not very clear. It appears to be somewhat nodular, but basically vermiform. Since the cell is colorless (no algal symbionts, no cortical pigments) that would make this
Stentor roeselii.
Stentor muelleri is also colorless, but has a "string of beads" (moniliform) macronucleus. Unfortunately, it shares those traits with a recently-revived species called
S. katashimai, and colorless populations of
S. polymorphus have recently been found...so identification of good old
S. muelleri has gotten more difficult.
Re: Stentor roeselii? Stentor muelleri?
Posted: Tue May 17, 2022 2:51 pm
by woyjwjl
Bruce Taylor wrote: ↑Mon May 16, 2022 10:35 pm
You don't have to count hairs, but you do have to see the macronucleus.
It is visible in the last image, though not very clear. It appears to be somewhat nodular, but basically vermiform. Since the cell is colorless (no algal symbionts, no cortical pigments) that would make this
Stentor roeselii.
Stentor muelleri is also colorless, but has a "string of beads" (moniliform) macronucleus. Unfortunately, it shares those traits with a recently-revived species called
S. katashimai, and colorless populations of
S. polymorphus have recently been found...so identification of good old
S. muelleri has gotten more difficult.
Very great answer! I reviewed the video carefully and verified your opinion.
- vermiform macronucleus.jpg (19.16 KiB) Viewed 1054 times
Curious, is this your job or a hobby?
Re: Stentor roeselii? Stentor muelleri?
Posted: Tue May 17, 2022 5:03 pm
by Bruce Taylor
A hobby.
I should add that, whenever possible, you should try to identify populations of ciliates, rather than individual specimens. There can be a lot of normal variation within a species, and some have distinct phases of life, as well. For instance, the moniliform macronucleus of certain
Stentors undergoes condensation as the organism prepares for division, and the macronucleus may take on a nodular or vermiform appearance, or condense to a single bead. And the macronucleus of
Stentor roeselii will often appear quite lumpy, especially when the cell is contracted.