Petalomonas iugosus 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 : 520

Petalomonas iugosus Lee and Patterson , n. sp.

(fi gures 14k, 15h, i. Type micrograph: fi gure 15i)

Diagnosis. Petalomonas , cell heart-shaped, 11-12 Mm long, 8 Mm wide, with an indentation of the posterior end and three longitudinal ridges on the dorsal right half of the cell.

Description. Colourless, rigid and gliding cell. Cell heart-shaped, 11-12 Mm long and 8 Mm wide, fl attened, with an indentation in the posterior end of the cell. The left half of the cell is slightly longer than the right half. This species has three distinct longitudinal dorsal ridges running along the cell on the right half of the cell. There are two indistinct ventral ridges, the right one runs beneath the reservoir along the cell. One fl agellum emerges from the canal and is as long as the cell. The distal part of the fl agellum moves a little when the cell glides. The reservoir is situated anteriorly to the right of the antero-posterior axis of the cell. The nucleus is situated in a median position or just below the reservoir. Three cells observed.

Remarks. The species described here has the characteristics of the genus Petalomonas in being a rigid and fl attened heterotrophic euglenid, and in having one emergent fl agellum. Petalomonas iugosus can be distinguished by size from all species in the genus, excepting P. minor Larsen and Patterson, 1990 , P. minuta Hollande, 1942 and P. poosilla Larsen and Patterson, 1990 (see Huber-Pestalozzi, 1955; Larsen and Patterson, 1990). It can be distinguished from these species by the presence of three longitudinal ridges. Petalomonas iugosus is similar in general cell shape to P. steini var. cordiformis Christen, 1962 and P. triquetra Skvortzov, 1929 , but it is much smaller ( P. steini var. cordiformis 40-45 Mm, P. triquetra 30-33 Mm), and has three dorsal ridges rather than one dorsal keel ( P. steini var. cordiformis ) or one ventral keel ( P. triquetra ) (see Huber-Pestalozzi, 1955; Christen, 1962b).