Petalomonas mira var. bicarinata (Skuja, 1939)
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Simmelried
Phylogenetic tree: Petalomonas mira
Diagnosis:
- length 19 – 28 µm, width 13- 15 µm, thickness 8-9 µm
- body broadly ovoid
- dorso-ventrally flattened
- one flagellum
- two doral keels
- the keels converge anteriorly and posteriorly
- one keel extends beyond the posterior end
- ventral side flat
In 2007 I found a single specimen of Petalomonas mira var. bicarinata in Simmelried. The specimen was 28 µm long. This is slightly longer than Skuja indicates (19 – 22 µm) but within the natural variance. The most striking feature for identification are the two dorsal keels. One of them is elongated and forms an extended tip posteriorly. In addition, the ventral side is flat. The flagellum is approximately of body-length, consistent with the description by Skuja. The swimming style is slow and often the direction changes.
Fig. 1: Petalomonas mira var. bicarinata. L = 28 µm. A freely swimming specimen in ventral view. Obj. 100 X.
Fig. 2 a-d: Petalomonas mira var. bicarinata. L = 28 µm. A freely swimming specimen in dorsal view (a, c), in ventral view (b) and in apical view (d). The keel K1 is elongated and forms an extended tip posteriorly (s. Fig. 2b, arrow). Obj. 100 X.