Goniomonas paci

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 : 489-490

Goniomonas paci ®ca Larsen and Patterson, 1990

(fi gures 1e, 2f -h)

Description. Cell measuring 4-10 Mm long, 3-7 Mm wide, with several distinct longitudinal ridges on both sides of the cell. With a row of about seven to nine extrusomes near the anterior end of the cell which is truncated with the posterior end rounded. Two fl agella of similar length emerge from a small anterior depression and are directed anteriorly. When the cell is swimming, two fl agella diverge in different directions. Less common than G. amphinema .

Remarks. Previous reported length ranges are 3-15 Mm. G. paci ®ca has been found in marine sites in subtropical and tropical Australia, North Atlantic, Brazil, Denmark, England, Gulf of Finland, Hawaii and Panama ( Larsen and Patterson, 1990; Vørs, 1992a, 1992b; Patterson et al., 1993; Ekebom et al., 1996; Patterson and Simpson, 1996; Tong, 1997a; Tong et al., 1998). Goniomonas paci ®ca is distinguished from G. amphinema because G. amphinema has two fl agella of unequal length. Goniomonas paci ®ca is usually distinguished from Goniomonas truncata Stein, 1878 by having distinct longitudinal ridges and by its smaller size ( Larsen and Patterson, 1990; Vørs 1992a, 1992b). Ridges in G. amphinema may be hard to see ( Ekebom et al., 1996; Patterson and Simpson, 1996) and comparable ridges have now been observed in organisms assigned (with uncertainty) to G. truncata ( Ekelund and Patterson, 1997) . Additionally, the length ranges overlap between the two species ( G. paci ®ca, 4-15 Mm; G. truncata , 3-25 Mm). Goniomonas truncata was reported by Fresenius (1858), Bütschli (1878), Stein (1878), Ulehla (1911), Skuja (1939), Czosnowski (1948), Mignot (1965), Schuster (1968), Vørs (1992a, 1992b), Novarino et al. (1994) and Bernard et al. (1999) from marine and freshwater sites in Australia, Denmark, England, Gulf of Finland, Germany, Poland and USA. Goniomonas truncata lacks a clear identity (see discussion by Bernard et al., 1999) possibly because more than one species has been described under this name. Usually, it is considered to be found only in freshwater. Further study is required to give G. truncata and G. paci ®ca well-de fi ned identities.