Clautriavia cavus Lee et Patterson, 2000

Lee, Won Je, 2019, Small Free-Living Heterotrophic Flagellates from Marine Intertidal Sediments of the Sydney Region, Australia, Acta Protozoologica 58 (4), pp. 167-189 : 183

Clautriavia cavus Lee et Patterson, 2000

Figs 5c–d

Description: Cell outline is oval to oblong. Cells are 7.5 to 12 µm long, flattened and rigid. One flagellum directed posteriorly emerges from a ventral subapical depression, is 1.5 to 2 times the length of the cell and makes close contact with the substrate when the cell is gliding. The cells have a shallow, wide ventral groove, which is easy to overlook. The ventral face of the cell appears to be slightly concave. The cell surface may be rather warty and food particles are seen in the posterior part of the cell. The cells glide slowly and smoothly with the posterior part slightly raised above the substrate. Often observed, but not in large numbers. Description based on the observations of 8 cells.

Remarks: This species was reported from marine sites in subtropical Australia, England, Korea and White Sea ( Tong 1994; Lee and Patterson 2000; Al-Qassab et al. 2002; Lee 2002b, 2006b; Tikhonenkov et al. 2006) and reported cell lengths are 5–12 µm. Clautriavia is reminiscent of Protaspa and Allantion, but can be recognised from Protaspa by having only one flagellum. Clautriavia cavus is less easy to distinguish from Allantion because Clautriavia lacks a rostral prominence at the anterior end of the cell and has a concave ventral face. The genus Clautriavia to date contains four nominal species; C. cavus Lee et Patterson, 2000 , C. mobilis Massart, 1900 , C. parva Schouteden, 1907 , C. biflagellata Chantangsi et Leander, 2010 ( Chantangsi and Leander 2010). Clautriavia cavus differs from C. mobilis because C. mobilis is twice as large, has a relatively short flagellum and has a nucleus at the right posterior of the cell. Clautriavia parva may be the gliding stage of Metromonas ( Lee and Patterson 2000) . This species is not easily distinguished from C. biflagellata having two flagella because both species have a similar cell shape and the cell length ranges are overlapped. In addition, the shorter flagellum in C. biflagellata is very difficult to observe under the light microscopy because it is very short. Clautriavia biflagellata may be a junior synonym of C. cavus . Further studies are needed to distinguish these two species.

Figures

Fig. 5. (a) Protaspa verrucosa, note ventral groove. (b) Thaumatomastix sp., general appearance of cell and showing a layer of body scales. (c)–(d) Clautriavia cavus, general appearance of different cells, (c) cell from Lee and Patterson (2000). (e) Gweamonas unicus, note coiled flagellum and flagellar insertion. (f)–(h) Eoramonas jungensis sp. nov., showing general appearance of different cells, note flagellar insertion and beating pattern of anterior flagellum. (i)–(j) Glissandra similis, showing general appearance of different cells, note the ventral groove. (k) Phyllomitus undulans, note two flagella adhering each other, from Lee (2002a). (l)–(m) Protist 1, showing general appearance, note flagellar insertion. (n) Protist 2, showing general appearance, note collar and two emergent flagella.All micrographs are DIC images. Scale bar in (h) = 5 μm for (e)–(h) and in (n) = 10 μm for other figures.