Notosolenus ostium 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 : 511

Notosolenus ostium Larsen and Patterson, 1990

(fi gures 9i, 10o, 11m)

Description. Cell outline elongate ovate, 27 -56 Mm long, 15-24 Mm wide, the ratio of length to width is 1.5 to 3.2. Dorso-ventrally fl attened, dorsally with a median longitudinal groove, and ventrally a wide groove and four fi ne stripes. With a small obliquely oriented ingestion organelle with two fi ne rods near the anterior. The majority of the cells have a rounded posterior end but some cells have a slightly pointed posterior end. The reservoir is anteriorly situated in the right side of the cell and the nucleus in the left side. Two fl agella of unequal length; the anterior fl agellum is as long as the cell, held forward in gliding cells. The posterior fl agellum is about 0.2-0.6 times the length of the cell. The organism contained eukaryotic algal material up to 8 Mm long. Moves by smooth gliding with the anterior fl agellum. Common in late culture. Description based on observations of 30 cells.

Remarks. Previously reported lengths of cells from marine sites (subtropical and tropical Australia, Brazil, Fiji, Hawaii and Panama) range from 24 to 40 Mm ( Larsen and Patterson, 1990; Ekebom et al., 1996; Patterson and Simpson, 1996). Our observations extend the size range. We observed two cells measuring 43 and 56 Mm which may be assignable to N. ostium . Notosolenus ostium is easily distinguished from other species of Notosolenus by its deep dorsal groove and visible ingestion organelle, which has not been seen in other species of the genus except N. triangularis Larsen and Patterson, 1990. Notosolenus ostium is similar to N. lagenos Skuja, 1948 in length and general appearance and in having a very short recurrent fl agellum, but N. ostium can be distinguished by its wide grooves on both faces of the cell.