Ploeotia corrugata 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 : 526

Ploeotia corrugata Larsen and Patterson, 1990

(fi gures 17a, 18a -d)

Description. Cell measuring 8-20 Mm long (mostly 13-15 Mm) and 6-12 Mm wide. Cell outline elliptical to rhomboid, dorsally convex and ventrally fl attened. Seven ridges on the dorsal side; two of which appear as a marginal rim. The right half of the cell is slightly thicker than the left, with a slight ridge down the middle of the ventral side against which the recurrent fl agellum lies. The posterior end of the cell is indented. With two fl agella of unequal length; the anterior fl agellum is about the same length as the cell, beats rapidly from side to side with an irregular wave motion when the cell glides. The posterior fl agellum is about 1.5-2.2 times the length of the cell and tapers slightly towards the posterior end of the cell. The reservoir is on the left ventral side of the cell and the ingestion organelle with two rods extends from right anterior of cell to left posterior. Moves by smooth gliding. Common, description based on observations of 15 cells.

Remarks. This species was fi rst described by Larsen and Patterson (1990) from subtropical and tropical Australia, North Atlantic, Brazil, Danish Wadden Sea, Denmark, England, Fiji, Hawaii, Panama and has also been reported from the USA, and previous reported cell length ranges from 7 to 15 Mm ( Larsen and Patterson, 1990; Patterson et al., 1993; Farmer and Triemer, 1994; Ekebom et al., 1996; Patterson and Simpson, 1996; Tong et al., 1998). It is widespread and often common, but not in the winter season. The cells described here are generally in agreement with the observations of Ekebom et al. (1996) and of Farmer and Triemer (1994) under the name Lentomonas applanatum (basionym Entosiphon applanatum Preisig, 1979 ). We suspect that L. applanatum is synonymous with P. corrugata ( Ekebom et al., 1996) because the size ranges of the two species overlap; L. applanatum , about 10 Mm, P. corrugata , 7-15 Mm, and both species have seven ridges on the dorsal side of the cell. However, the species cannot be synonymized until the uncertainty with respect to protrusion of the ingestion apparatus of L. applanatum sensu Farmer and Triemer is clari fi ed. Ploeotia corrugata resembles P. decipiens Larsen and Patterson, 1990 in general appearance, but it is distinguished by the number and prominence of the dorsal ridges, slightly smaller size and indented posterior end.