Carchesium polypinum

(Linnaeus, 1758) Ehrenberg, 1830

Most likely ID: n.a.

 

Synonym: n.a.

 

Sampling location: Simmelried

 

Phylogenetic tree: Carchesium polypinum

 

Diagnosis: 

  • zooids elongated bell-shaped, often tilted to the side
  • length of zooids 80–140 µm
  • zooids contract almost spherically
  • macronucleus J-shaped in the longitudinal axis
  • one micronucleus
  • one contractile vacuole
  • peristome collar 60–135 µm in diameter
  • pellicle finely striated
  • colonies tree-shaped with branched stalks, up to 2 mm heigh
  • lower part of the colonies is an unbranched main stem
  • stalks contract in tight helix
  • myonemes in the branches are interrupted
Carchesium-polypinum
Carchesium polypinum

I find Carchesium polypinum mainly in old samples from the Simmelried. The colonies of this pertrich ciliate are easy to recognize by the tree-like structure and the non-branched stalk. Carchesium polypinum can be easily distinguished from other colony-forming peritrich ciliates, whose peduncles also contract helically, by the interrupted myonemes at the branching points (s. figs. 3, 4 and 5). This interruption of myonemes causes zooids and also individual branches of colonies to contract independently. In the similar genus Zoothamnium, the myonemes are not interrupted, causing the entire colony to always contract synchronously. A distinguishing feature from Vorticella species is the stalk thickness. In Vorticella, the stalk is always < 10 µm thick, whereas in Carchesium polypinum it is thicker than 10 µm (s. fig. 6). Comparable Epistylis species (e.g. Epistylis procumbens) do not have a central myoneme in the stalk and therefore cannot contract.

Carchesium-polypinum

Fig. 1: Carchesium polypinum. Overview of a colony with a length of 1600 µm. Obj. 10 X.

Carchesium-polypinum

Fig. 2: Carchesium polypinum. Detail of the colony shown in fig. 1. Obj. 20 X.

Carchesium-polypinum

Fig. 3: Carchesium polypinum. L = 90–106 µm (of zooids). The zooids of the colony shown in fig. 1. Note the interrupted myoneme (IM) at the branch of the stalk. Obj. 40 X.

Carchesium-polypinum

Fig. 4: Carchesium polypinum. The interrupted myoneme (arrow) at the branch of the stalk in a slightly squashed colony. Obj. 40 X.

Carchesium-polypinum

Fig. 5: Carchesium polypinum. The interruption of the myoneme (IM) in detail. My = myoneme of the stalk. Obj. 40 X.

Carchesium-polypinum

Fig. 6: Carchesium polypinum. The spiralized stalk with the central myoneme (MY). The myoneme is surrounded by numerous mitochondria (Mit). Obj. 100 X.

Carchesium-polypinum

Fig. 7: Carchesium polypinum. The fine striation of the pellicle. In this specimen, there are 15 lines per 10 µm. AW = aboral ciliary wreath. Obj. 100 X.

Carchesium-polypinum

Fig. 8: Carchesium polypinum. The J-shaped macronucleus (Ma) and the micronucleus (Mi) in a strongly squashed specimen. CV = contractile vacuole. Obj. 100 X.