In a few shots you can just see the "spokes".
I don't really know what diatom it is, Surirella might be wrong
Water sample from depression on lapwing protection area. Sample taken on February 3rd at 3 p.m. Transferred part of the sample into a Petri dish today, February 8th.
The observed animal seems to have built a kind of protective shell that reminds me of caddis flies. You can see how it eats out in front and retreats when threatened.
Wasserprobe aus Senke auf Kiebitz-Schutzfläche. Probe entnommen am 3. Februar um 15 Uhr. Einen Teil der Probe heute 8. Februar in eine Petrischale umgefüllt.
Das beobachtete Tierchen scheint eine Art Schutzhülle gebaut zu haben, dass mich an Köcherfliegen erinnert. Es ist zu sehen wie es vorne raus frisst und sich bei Gefahr zurück zieht.
The suctorian Metacineta mystacina from an ephemeral rainwater puddle on a neglected lawn. Imaged in Nomarski DIC on Olympus BH2S using SPlanapo 40 0.95 objective plus variable phone camera cropping on Samsung Galaxy S9+. This is likely M. mystecina var. brevipes with a very short stalk on the lorica (see below). Actually, Metacineta does not have a true stalk but rather a hollow narrowing extension of the main lorica.
The cell measures 38 um in diameter and the six-sided lorica measures 40 um in diameter. I could only obtain an apical view of the animal despite attemps to wrangle it into a side view by tapping on and moving the coverglass. Thus, I could not assess the presence of and morphology of a basal stalk by optical sectioning through the animal. The lorica is subdivided at the anterior or distal margin into six stellately-arranged acuminate, triangular, valve-like lobes through which the tentacles emerge. I considered a similar species, Solenophrya micraster (Metacineta micraster) whose lorica is attached by its lorica direct to the substratum without an intervening stalk but that species has a pentagonal not hexagonal lorica with 5 tentacles fascicles. There is an ovoid nacronucleus and a single contractile vacuole below the level of the macronucleus.
Differential diagnosis: Only the variety typica is characterized here; are the essential characteristics of the other varieties can be found in the Taxonomy chapter.
1) Shell of the adult sessile specimens 55-250 x 35-80 um. Ratio of length of the wide to the narrow lorica 1:3 to 2:1, usually about 1:1.
2) Cell shape roundish. At the apical end 6 bundles with 6-17 (usually 8-12) tentacles each. tentacle up to 150 um long), distal end spherical.
3) Lorica narrow to broad funnel-shaped and not flattened, with 6 triangular lobes almost at the front completely closed. Tentacles protrude from the radial gaps between the lobes. Width of the stalk, a stem-like narrowing halfway up is about 4-8 um.
4) Macronucleus spherical approximately in the center of the cell. 1 spherical micronucleus.
5) Contractile vacuole subapical .
6) Swarmers 60-70 x 25-35 um, approximately ellipsoid, with 17-28 rows of cilia.
7) Resting cyst in top view, lemon-shaped, with a strong stalk attached to the substrate.
To differentiate the varieties taxonomy. Metacineta micrasler (PENARD) has 5 shell gaps and is usually attached to the substrate without a stalk-like narrowing. In Metacineta macrocaulis (STOKES), the shell is open apically and has 8-9 ribs (no columns) and a relatively long and thin "stem" . Metacineta longipes (MERESCHKOVSKY) is >1000 um long. Metacineta cuspidata resembles the short-stemmed form brevipes can only be clearly distinguished by their long, winding tentacles. Acineta species have a highly compressed shell and only 2 bundles of tentacles. For identification are special Features 1, 3 are important.
Foisner et al write: The taxonomic status of the different forms of M. mystacina is not yet clear. We follow RIEDER (1985), who examined this group in great detail; he distinguishes 5 varieties, viz: typica (6 lorica columns, stem-like part of the housing (= Stylotheca) usually about as long as the width; brevipes (6 lorical slits, stylotheca very short; yoshii (8 lorica gaps, stylotheca short and noticeably thick; bilateralis (6 lorica columns, shell bilaterally symmetrical, stylotheca very short; and angularls (only 2 housing columns, housing bilaterally symmetrical, stylotheca short). MATTHES (1988) looks at the typical form only brevipes and bilateralls as varieties, the others he lists as species. In practice you will be comfortable
all forms mentioned are best referred to as M. mystacina s.l. describe.
Taxonomische und ökologische Revision der Ciliaten des Saprobiensystems, Band IV: Gymnostomatea, Loxodes, Suctoria. January 1995
Publisher: Bayerisches Landesamt für Wasserwirtschaft. Wilhelm Foissner,Helmut Berger, Hubert Blatterer, F. Kohmann. pp 481-7.
6 'Arme'!?.
Patches of bright pink/purple film growing in a sulfur spring.
In a pond water sample. 3.5 months after collecting.
Video: https://www.youtube.com/shorts/DF4ZzyE0e7s