Mayorella augusta (Schaeffer, 1926)
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Simmelried
Phylogenetic tree: Mayorella augusta
Diagnosis:
- floating form triangular, sometimes divided in two branches (Y-shaped)
- pseudopodia mammilliform or conical
- length 200–350 µm
- one contractile vacuole
- one spherical nucleus (16–27 µm) with a large, central nucleolus
- nucleolus sometimes with granular structure
- crystals in the cytoplasm attached to spherical bodies
I find Mayorella augusta comparatively frequently in the Simmelried. The specimens in my population were on average 220 µm long. This is larger than the smaller species Mayorella penardi (50–125 µm). The species Mayorella bigemma, which is about the same size, differs from Mayorella augusta by so-called sub-pseudopodia, which are conical pseudopodia that are protrude laterally to the direction of flow. During locomotion, Mayorella augusta often forms Y-shaped stages in which the pseudopodia temporarily flow in two different directions (s. figs. 1 b, 2 a and 4 d). Another important characteristic of Mayorella augusta is the size of the nucleus, which is 16–27 µm in diameter and has a large, spherical nucleolus (s. fig. 6). The cytoplasm also contains birefringent crystals, which are always connected to a spherical body (s. drawing above and fig. 5). These pairs were found in all the specimens I observed. The composition of these paired bodies and what function they have is not known.
More images and information on Mayorella augusta: Ferry Siemensma-Microworld-Mayorella augusta
Fig. 1 a-b: Mayorella augusta. L = 220 µm. A free-flowing specimen. Note the Y-shaped state branched in two pseudopodia (b). Obj. 40 X.
Fig. 2 a-d: Mayorella augusta. L = 205 µm. A second, free-flowing specimen. CV = contractile vacuole, Nu = nucleus. Obj. 60 X.
Fig. 3 a-d: Mayorella augusta. L = 205 µm. A third, free-flowing specimen. Obj. 60 X.
Fig. 4 a-d: Mayorella augusta. L = 220 µm. A fourth, free-flowing specimen. Obj. 60 X.
Fig. 5: Mayorella augusta. The birefringend crystals in the cytoplasm are attached to spherical bodies (arrows). Obj. 100 X.
Fig. 6: Mayorella augusta. The nucleus (Nu) with a central nucleolus (Nuc) in detail. The diameter of the nucleus in this specimen is 26 µm. Obj. 100 X.