Euplotes patella

(Müller, 1773) Ehrenberg, 1831

Most likely ID: n.a.

 

Synonym: n.a.

 

Sampling location: Simmelried. Purren pond, Bussenried, Pond of the convent Hegne, Pond of the waste disposal company Constance, Mühlweiher Litzelstetten, Hagstaffel pond

 

Phylogenetic tree: Euplotes patella

 

Diagnosis: 

  • body broadly ellipsoid, dorso-ventrally flattened
  • pellicle hyaline, rigid
  • length 90–120 µm
  • oral apparatus wide open, adoral zone reaches 70 % body length

  • ventral side with 6 frontal cirri, 2 frontoventral cirri, 5 transverse cirri, 1 buccal cirrus, 2 left marginal cirri, 2 caudal cirri

  • macronucleus C-shaped
  • one spherical micronucleus, clearly separeted from macronucleus
  • one contractile vacuole on right side below cell equator
  • dorsal side with weak ribs, 9 rows of short cilia
Euplotes-patella
Euplotes patella

Euplotes patella is one of the most common hypotriche ciliates. I find it in almost all of sampling sites. It is best observed on the floating coverslip, where it likes to settle.

 

The specimens in my population of Euplotes patella were mostly around 100 µm long. The ventral ciliature of Euplotes patella is not quite as complicated as that of other hypotriche ciliates. Thus the left marginal row of cirri is reduced to 2 cirri. There are also only two caudal cirri and 2 frontoventral cirri (s. fig. 3 a). The oral apparatus is wide open. The adoral zone can reach up to 70 % of the body length. The macronucleus is C-shaped with a clearly separated micronucleus. The contractile vacuole is located on the right side of the body below the cell equator.

 

The species within the genus Euplotes are difficult to distinguish from Euplotes patella. The two species Euplotes affinis and Euplotes moebiusi are significantly smaller than 100 µm. Euplotes eurystomus is clearly larger than 140 µm and the adoral zone is S-shaped. Finally, Euplotes aediculatus is larger than 100 µm and has an adoral zone that extends over the left margin of the body.

Euplotes-patella

Fig. 1 a-c: Euplotes patella. L = 88 µm. A freely swimming specimen from ventral. CV = contractile vacuole. Obj. 60 X.

Euplotes-patella

Fig. 2 a-c: Euplotes patella. L = 96 µm. A specimen crawling on a floating coverslip from ventral. AMZ = adoral zone of membranelles, CC = one of the two caudal cirri, CV = contractile vacuole, FVC = one of the two frontoventral cirri, LMC = left marginal cirri, TC = transverse cirri, UM = undulating membrane. Obj. 60 X.

Euplotes-patella

Fig. 3: Euplotes patella. L = 96 µm. The same specimen as shown in fig. 2 a-c with focal on the micronucleus (Mi) clearly separated from the macronucleus (Ma). Only parts of the C-shaped macronucleus are in the plane of focus. Obj. 60 X.

Euplotes-patella

Fig. 4 a-b: Euplotes patella. L = 110 µm. Two focal plane of the ventral ciliature. AMZ = adoral zone of membranelles, BC = buccal cirrus, CC = one of the two caudal cirri, FC = frontal cirri, FVC = frontoventral cirri, LMC = left marginal cirri, TC = transverse cirri. Obj. 100 X.

Euplotes-patella

Fig. 5: Euplotes patella. The C-shaped macronucleus (arrows) in a squashed specimen. Mi ? = probably the micronucleus. Obj. 100 X.