H.J.Marchant, in Marchant et al. (1989: 168, figs 4 (holotype), 6, 12-21, 23-25)
Cells spherical to slightly ovoid, 2.8–5 µm diameter, with 2 unequal flagella arising from anterior part of cell. Cell body and flagella covered with scales of different types. Body scales virtually flat, of 2 types arranged in separate layers, with smaller scales overlain by larger ones; inner (smaller) scales like those of the flagella; outer (larger) scales (280–) 360 (–470) nm diameter, with the same arrangement of concentric threads as smaller scales but with only 6 radial spokes. Long flagellum 8.6–21.3 µm long; short flagellum c. 1 µm long. Flagella scales arranged in rows, flat, scalloped in outline, (200–) 240 (–270) nm diameter, comprising 7 radial spokes and 3 concentric threads; 2 inner concentric threads forming a pair, outer concentric thread attached to radial spokes close to the junctions of the spokes producing the scalloped outline; flagella also sparsely decorated with hair-scales 0.51 µm long and 30 nm diameter, tapering proximally, with a delicate cross-banded structure with a periodicity of c. 12 nm.
Pack-ice, Weddell Sea (Marchant et al., 1989).
The terminal tuft of hair-scales on the longer flagellum of M. squamata is sometimes found on M. antarctica (Marchant et al., 1989). The two species are difficult to distinguish from one another without SEM preparations.