Petalomonas intortus 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 : 518

Petalomonas intortus Lee and Patterson , n. sp.

(fi gures 14b, 15f, g. Type micrograph: fi gure 15g)

Diagnosis. Petalomonas , 5-11 Mm long, rounded body, fl attened, with small particles adhering externally and with about 10 curving striations on the ventral face.

Description. Cell outline rounded, 5-11 Mm long, very fl attened. With tiny bodies adhering to the cell surface and with about 10 striations following a counterclockwise path on the ventral face of the cell. No structures visible on the dorsal face. One fl agellum emerges from the fl agellar canal, is slightly thickened and is about 1.5-1.7 times the cell length. Cells move slowly with the emergent fl agellum directed forwards and with most movement in the distal part of the fl agellum in contact with the substratum. The ovate reservoir is situated in the left-hand side but adjacent to the antero-posterior axis of the cell. The nucleus is in the right anterior side of the cell. Not metabolic. Rare, description based on observations of seven cells.

Remarks. We assign this species to Petalomonas because it is rigid, fl attened, and has one emergent fl agellum and no visible mouth. Petalomonas intortus is characterized by its striations on the ventral face of the cell and the particles adhering to the cell surface. This species is distinguished from most other species in Petalomonas because of the adhering particles. Of those species with reported adhering elements, P. intortus is distinguished from P. prototheca Skuja, 1948 by its smaller size, its round shape and the lack of a short neck, from P. punctatostriat a Skuja, 1939 by its fi ner spiral striations, and from P. boadicea which has rhomboid excrescences and a shorter fl agellum. Petalomonas intortus is similar in general appearance to Jenningsia granuliferum ( Penard, 1890) Lee et al., 1999 (basionym, Peranema granulifera ), but it is round whereas J. granuliferum is oval; and J. granuliferum has spiral striations. Jenningsia granuliferum may have to be transferred to Petalomonas because it lacks a mouth and no reference has been made to metaboly. Petalomonas ornata Skvortzov, 1957 has a reservoir and nucleus at the same position as P. intortus but lacks the adhering particles; it is about 11-15 Mm long and has no striations (see Skvortzov, 1957; Larsen and Patterson, 1990).