Cercomonas sp.

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 : 62

Cercomonas sp. ( Figs 3d–f )

Observation: Cell outline is pyriform. Cells are 7 to 15 µm long and flexible. Two flagella are of simi- lar thickness and appear to be acronematic. The anterior flagellum is about 3.5 times the cell length, beats from side to side with entire length, and the basal part of the flagellum adheres to the anterior part of the cell. The posterior flagellum is about 4 times the cell length, may adhere to the body surface for part of its length and beats slowly from side to side as the cells glide. The cells glide with the flagella in contact with the sub- strate, and during gliding the anterior part of the cell is elongated. Rarely observed.

Remarks: This species is similar to Cercomonas granulatus , but it lacks a row of refractile bodies on the ventral side, which is one of the diagnostic characters for C. granulatus . It is also similar to the cells found in Cape Tribulation under the name Cercomonas granulatus ( Lee 2006b) . Most similar nominal taxa to Cercomonas granulatus have been compared and discussed by Lee and Patterson (2000) and Lee (2006b). Recently Bass et al. (2009) described 66 species from cercomonads, and they also said that it is difficult to describe any particular species adequately because of their morphological plasticity and behavioural diversity. That is, it is not easy to distinguish cercomonad species by light microscopy. Probably the composition of the cercomonads is still uncertain and there are many synonyms in this group.

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.