H.A.Thomsen, Kosman & Ikävalko (1995: 175, figs 3 (holotype), 4–11)
Subphylum Heterokonta, Genera Incertae Sedis
Takahashi (1981a: 11, pl. 7, fig. 30, as “sp. S”), Daugbjerg & Vørs (1992: 39, figs 18.3, 18.4, as Thaumatomastix sp. 2), Vørs (1993a: fig. 23, as Thaumatomastix sp. 2)
Cells solitary, spherical to ovoid, slightly compressed, 6–19 µm long, 6–15 µm diameter, covered with scales, biflagellate. Flagella emerging from an anterior invagination, dissimilar, one 15–20 µm long, naked, the other c. 8 µm long, thin, covered with oval scales. Body scales form a corona around the cell (LM); scale base triangular with rounded corners, supporting 3 rods that fuse to form a conspicuous central spine c. 2 µm long.
Coastal waters near Davis Station, East Antarctica; sea-ice, Weddell Sea (Thomsen et al., 1995); Lützow-Holm Bay (Takahashi, 1981a); Arctic Canada (Vørs, 1993a).
Although Thomsen et al. (1995) stated that T. splendida is especially adapted to life in sea-ice brine channels or pockets, isolated scales have been observed in Southern Ocean water samples. Specimens from Davis Station sea-ice were usually smaller (6–10 µm long) than the holotype (12–19 µm).