Thaumatomastix setifera Lauterborn, 1896

Lee, Won Je, 2015, Small Free-Living Heterotrophic Flagellates from Marine Sediments of Gippsland Basin, South-Eastern Australia, Acta Protozoologica 54 (1), pp. 53-76 : 63

Thaumatomastix setifera Lauterborn, 1896 ( Figs 1i , 3j–k )

Observation: Gliding heterotrophic flagellate. Cells are oval, 14–17 µm long and slightly dorso-ventrally flattened. The cells have a layer of visible scales and delicate spines. A ventral groove extends from the anterior depression to the posterior end of the cell. Two flagella insert to the widely opened anterior depression on the ventral face of the cell. The anterior flagellum is 0.6 to 1 times the cell length and beats from side to side. The posterior flagellum is 1.2 to 1.6 times the cell length and trails. The nucleus is anteriorly located. The cells move slowly by gliding. Two cells were observed.

Remarks: The species described here is assigned to Thaumatomastix setifera although pseudopodia have not been seen. Subsequent to the original description ( Lauterborn 1896), T. setifera was found at a marine site in Hawaii ( Larsen and Patterson 1990) and at a freshwater site in Latvia ( Skuja 1939). The previously reported cell lengths are 16–28 µm. Generally, the description here is in good agreement with previous observations. This species resembles Protaspis verrucosa , but can be distinguished by the layer of visible scales and the spines. However, it is difficult to distinguish from T. salina (7–12 µm), T. splendida (12–19 µm) and T. tripus (8–15 µm) because their size ranges overlap, and they can be easily identified on the basis of the shape of body scales visible by electron microscopy. They may not be distinguished by light microscopy.

Figures

Fig. 1. a – Chilomastix cuspidata, b – Rhynchopus amitus, c – Spironema multiciliatum, d – Psammosa unguis nov. comb., e – Apusomonas sp., f – Rhynchobodo formica, g – Mantamonas plastica, h – Roombia truncata, i – Thaumatomastix setifera, j – Ancyromonas impluvium nov. spec., k – Helkesimastix faecicola, l – Kurnaimonas celerisnov. spec., m – Sinistermonas sinistrorsus nov. spec., n – Kiitoksia kaloista, o – Protist ‘1’. Scale bar: 10 µm for all figures.

Fig. 3. a–b –Rhynchobodo formica; c –Massisteria marina, general appearance of cell showing pseudopodia and flagella (arrow); d–f – Cercomonas sp.; d – note two acronematic flagella; e – general appearance; f – note flagellar orientation; g–h – Roombia truncata, note cell attached to the substrate by the tip of the posterior flagellum and note extrusomes; i – Protaspa obliqua, note anterior protrusion;j–k – Thaumatomastix setifera, note spines around the body; j – general appearance of cell; k – ventral face showing a deep groove and pseudopodia; l–m – Ancyromonas sigmoides of different cells; l – note slightly thick anterior flagellum with acronematic tip and broad rostrum; m – note thick anterior flagellum and acute rostrum; n–p – Ancyromonas impluvium nov. spec., showing general appearance of cell and note flagellar insertion.All micrographs are DIC images with the exceptions of (d) and (p) which are phase contrast images. Scale bar: 5 µm for all figures.