Cafeteria marsupialis Larsen and Patterson, 1990

Lee, Won Je & Patterson, David J., 2000, Heterotrophic flagellates (Protista) from marine sediments of Botany Bay, Australia, Journal of Natural History 34, pp. 483-562 : 536

Cafeteria marsupialis Larsen and Patterson, 1990

(fi gures 20f, 21b, c)

Description. Biflagellated, D-shaped cells somewhat variable in shape, when attached 5-12 Mm long, mostly about 7-8 Mm long, and 5-10 Mm wide; up to 7-10 Mm long and 3-5 Mm wide when swimming. Attach to the substratum by the tip of the posterior fl agellum, which lies in a deep ventral groove. The anterior fl agellum is directed normal to the groove. The organism may feed on suspended bacteria, which are drawn towards the body by the activity of the anterior fl agellum, entering along a curved channel at the posterior end of the ventral groove. The anterior fl agellum of the attached cell is about 1.5-2 times the cell length and the posterior fl agellum is slightly longer than the cell. A single nucleus with a rounded nucleolus lies just below the insertion of the fl agella. The cell body may include many—sometimes large—food vacuoles. Undigested residues of food are egested by the fusion of old food vacuoles with the plasma membrane. Swimming cells are more rounded, with anterior fl agellum directed to the anterior, recurrent fl agellum trailing. It often occurs with Carpediemonas membranifera and C. bialata . More frequent in slightly anaerobic preparations. Description based on observations of 95 cells.

Remarks. This organism has the characteristics of the genus Cafeteria in being a stramenopile (anterior fl agellum which draws water towards the body of the cell and is therefore hispid) which adheres to the substratum by the tip of the posterior fl agellum and has no peri-flagellar collar. It differs from other species in the genus by the large ventral pocket and posterior curving food ingestion region. A size range 5-15 Mm has previously been reported by Larsen and Patterson (1990) from tropical Australia and Brazil, and by Ekebom et al. (1996) from tropical Australia. The organism described here may graze on large bacteria as long as 0.7 times the cell length.