Notosolenus scutulum 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 : 513-514

Notosolenus scutulum Larsen and Patterson, 1990

(fi gures 9h, 11i -l)

Description. Cell measuring about 9-15 Mm long and 6.5-12 Mm wide, fl attened. Cells are anteriorly acute and posteriorly wide with a posterior prominence. The anterior fl agellum is about 1.5-2.0 times the cell length and the trailing posterior fl agellum is about 0.3-0.5 times the cell length. There is a deep narrow longitudinal dorsal groove which widens posteriorly and a ventral groove which also widens posteriorly. The reservoir is in the right-hand side of the cell and the nucleus is in the left side. Cells contained lots of food materials. Moves slowly by gliding. Rarely observed.

Remarks. Notosolenus scutulum was recorded from marine sites in Brazil by Larsen and Patterson (1990). Cells observed by us have a deep longitudinal dorsal groove, a ventral groove which widens out posteriorly and a posterior prominence, and one of three subtly different pro fi les (fi gures 11j -l)—which we regard here as conspeci fi c.

Notosolenus scutulum is characterized by a deep longitudinal dorsal groove, a ventral groove which widens out posteriorly, and a posterior point. It is similar in size, shape, dorsal groove and posterior point to N. skujai described by Suxena (1955). There are minor differences: N. skujai has a broad dorsal groove and its nucleus is posterior to the middle of the cell, while N. scutulum has a narrow dorsal groove which is more visible than suggested by Suxena’s drawings, and a ventral groove, and the nucleus is more central. We have seen no marginal gutters as are suggested by Suxena’ s drawings but not mentioned in the text. Notosolenus scutulum is similar to N. orbicularis in having a dorsal groove, but N. orbicularis Stokes, 1884 has no posterior prominence and has a very wide dorsal groove. This species looks like N. triangularis Larsen and Patterson, 1990, but N. triangularis is double the size (28 Mm), has a small visible mouth and a triangular reservoir. Notosolenus scutulum is similar in size to N. rhombicus ( Skuja, 1939) Larsen, 1987, but N. rhombicus has a smooth pellicle, a tiny collar surrounding the canal opening and no posterior point (see Larsen, 1987). This species is also similar to N. ostium Larsen and Patterson, 1990 in having a deep longitudinal groove and a ventral groove, but is distinguished because N. ostium has ventrally four fi ne pellicular stripes, has a visible mouth, is larger (20-56 Mm), and has a short posterior fl agellum relative to the cell length.

Notosolenus cfr. tamanduensis Larsen and Patterson, 1990 (fi gures 12a, 13a, b)

Description. Cell outline ovate, about 15 Mm long and 11 Mm wide, dorso-ventrall y fl attened, with a short neck around the fl agellar canal. With a thin lateral fl ange in the left margin of the cell. This species has in total four ridges: two broad shallow ridges on both the ventral and dorsal faces of the cell and two fi ne ridges on the broad ventral ridge. The posterior end has a wedge-shaped protrusion, which is extended from the broad ridges. The anterior fl agellum is as long as the cell and the posterior fl agellum is about 0.8 times the cell length. The reservoir is rounded and situated in the right side of the cell, and the nucleus is in the left side of the cell and adjacent to the centre of the cell. Moves slowly by gliding. Rare.

Remarks. One cell observed. This species is similar to N. tamanduensi s described by Larsen and Patterson (1990) from a marine site in Brazil. There are minor differences between our cell and N. tamanduensi s: our cell was about half the size (29 Mm) reported by Larsen and Patterson (1990) and we also have not seen an ingestion organelle, but that may be because of lack of material.