Notosolenus hemicircularis Lee and Patterson, 2000

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 : 509-510

Notosolenus hemicircularis Lee and Patterson , n. sp.

(fi gures 9d, 10i -l. Type micrograph: fi gure 10i)

Diagnosis. Notosolenus , 9-10 Mm long, 6-7 Mm wide, ventrally fl attened, with a semicircular hyaline collar around a short neck and with fi ve dorsal keels and three fi ne ventral ridges.

Description. Colourless, 9-10 Mm long and 6-7 Mm wide, ventrally fl attened and dorsally convex. Both ends of the cell are pointed but there is a hyaline semicircular collar around the short anterior neck. This species has fi ve dorsal keels running along the cell. Ventrally there are three fi ne ridges. The right and left ventral ridges arise at the neck. The left ventral ridge curves slightly from the anterior to the posterior forming an arc. The mid-ventral ridge arises from a small protrusion near the anterior end of the cell. Two are unequal in length and are slightly thickened. The anterior fl agellum is about 1.2-1.4 times the length of the cell and the recurrent posterior fl agellum is about 0.5-1.0 times the cell length. The reservoir lies anteriorly in the right-hand side of the cell and the nucleus in the left-hand side. Moves by gliding. Rarely observed.

Remarks. This species has the characteristics of the genus Notosolenus in that it is a heterotrophic euglenid with a rigid, fl attened body, two emergent fl agella and no visible mouth, and moves by gliding. This species can be distinguished from other small species of Notosolenus such as N. apocamptus Stokes, 1884 and N. rhombicus Larsen, 1987 by the semicircular hyaline collar and the fi ve dorsal keels (see Huber-Pestalozzi, 1955; Larsen, 1987). Notosolenu s hemicircularis is similar in general shape to N. papilio Skuja, 1939 and N. urceolatus Larsen and Patterson, 1990 (see Skuja, 1939; Larsen and Patterson, 1990), but it can be distinguished from both species by its smaller size and its strongly developed semicircular hyaline collar. Notosolenus papilio also has a ventral groove and lateral wings.