Ancyromonas impluvium, Lee, 2015

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 : 64

Ancyromonas impluvium nov. spec. ( Figs 1j , 3n–o )

Diagnosis: Ancyromonas , cell 4 to 6 µm long, ovoid to roundish, somewhat laterally compressed. Two thickend flagella emerging from wide snout at anterior end of cell insert apically and are thin at tip.

Etymology: The name refers to ‘basin’.

Observation: Cells are ovoid to roundish, 3 to 6 µm long and somewhat laterally flattened. The cells have two thickened flagella, which insert separately by a shallow, wide snout at the anterior end of the cell. Both flagella are thin at the tip. The anterior flagellum is slightly longer than the cell and beats stiffly. The pos- terior flagellum is 2 to 3 times longer than the cell and is directed posteriorly. The nucleus is located subapically. Food materials are seen in the posterior end of the cell. Normally, the cells glide with the beating of the anterior flagellum, but at times glide slowly with the anterior flagellum directed to the rear ( Fig. 3o ). Com- monly observed.

Remarks: This species is assigned to Ancyromonas because it glides, is laterally compressed, and has one short flagellum emerging from the anterior end and one long trailing flagellum emerging subapically from the ventral depression. Ancyromonas impluvium is distinguished from Ancyromonas sinistra by the lack of a rugose flange on the left anterior-lateral margin of Ancyromonas sinistra . This species can be distinguished from other Ancyromonas species ( A. melba , A. micra , A. sigmoides , A. sinistra ) because it glides with the beating of the anterior flagellum and at times glides in the anterior flagellum helding down. It is similar to Heteromita globosa , which glides in the anterior flag- ellum helding down, but both flagella in H. globosa insert close together subapically. Ancyromonas impluvium is similar to Protaspa species in that the nucleus is located anteriorly, but is distinguished by the orientation of the flagella and because A. impluvium is laterally compressed.

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.