Coleps hirtus var. minor (Kahl, 1930)
Most likely ID: n.a.
Synonym: n. a.
Sampling location: Simmelried
Phylogenetic tree: Coleps hirtus var. minor
Diagnosis:
- length 35–45 µm
- cell has a barrel-shaped form
- contracile vacuole sub-terminal
- uniform ciliation
- 13 longitudinal rows of plates
- one caudal cilium (hard to see)
- macronucleus spherical
- apical mouth opening with basket
- posterior spines are broadened at the base
- shape of the “windows” in the carapace are rectangular with rounded corners
I first noticed Coleps hirtus var. minor in my samples when they occurred simultaneously with Coleps hirtus. The specimens gathered together with many Coleps hirtus at the surface of a sample taken from the Simmeried. A direct comparison shoes that Coleps hirtus var. minor is much smaller and also has a more stocky body compared to Coleps hirtus. Upon close inspection of the armour I could confirm the description by Kahl, that in this variety the “windows” in the armour are not pretzel-shaped (as described for Coleps hirtus), but rectangular with rounded corners (s. fig. 3). I could recognize the caudal cilium in the living specimens, but unfortunately the photographic documentation is not fully sufficient (s. fig. 2a). Because of the simultaneous occurrence with Coleps hirtus I can confirm Kahl’s opinion that Coleps hirtus var. minor is a constant form.
Fig. 1 a-d: Coleps hirtus var. minor. L = 45 µm. A freely swimming specimen. Obj. 40 X.
Fig. 2 a-b: Coleps hirtus var. minor. L = 45 µm. Two focal planes of a slightly squashed specimen. CC = caudal cilium, CV = contractile vacuole, Ma = macronucleus. Obj. 100 X.
Fig. 3: Coleps hirtus var. minor. The “windows” of the carapace (WC) are rectangular with rounded corners. Obj. 100 X.