Urotricha ovata (Kahl, 1926)
Most likely ID: n.a.
Phylogenetic tree: Urotricha ovata
- body ellipsoid, sometimes cylindrical
- length 38–53 µm
- 19–27 longitudinal rows of cilia
- cytopharynx apical
- fringe of scattered, inconspicuous extrusomes
- macronucleus globular with an adjacent micronucleus
- posterior sixth of body naked
- one caudal cilium
- movement jumping and spinning
Urotricha ovata is a widespread ciliate, which I could detect in almost all my localities. Especially in old samples with decaying plants it is often found.
It is easy to confuse Urotricha ovata with the similar species Urotricha armata. The latter, however, has a dense fringe of extrusomes arranged parallel to each other. In Urotricha ovata, the extrusomes are scattered under the pellicle and are also not arranged parallel to each other (s. figs. 2 a and 2 b). In addition, the number of longitudinal rows of cilia is in Urotricha armata much higher (35–51) than in Urotricha ovata, where there are only 19–27 rows (s. fig. 1 b).
Fig. 1 a-b: Urotricha ovata. L = 43 µm. Two focal planes of a freely swimming specimen. Note the longitudinal rows of cilia (CR). This specimen has 24 rows of cilia. CC = caudal cilium, CV = contractile vacuole, CP = cytopharynx, Ma = macronucleus, Mi = micronucleus. Obj. 60 X.
Fig. 2 a-d: Urotricha ovata. L = 43 µm. Four focal planes of a slightly squashed specimen. Note that the posterior sixth of the body is a cilia-free zone (CZ). CC = caudal cilium, CV = contractile vacuole, CP = cytopharynx, EX = extrusomes, Ma = macronucleus, OF = oral flaps. Obj. 100 X.