Polyoeca dichotoma (Kent, 1881)

Aydin, Esra Elif & Lee, Won Je, 2012, Free-living Heterotrophic Flagellates from Intertidal Sediments of Saros Bay, Aegean Sea (Turkey), Acta Protozoologica 51 (2), pp. 119-137 : 132

Polyoeca dichotoma Kent 1880 ( Figs 3i , 4i)

Observation: Cell is about 5 μm long and 2.5 μm wide, and located in a lorica which is about 15 μm long. The anterior part of the lorica has a broad opening and is about 3 times broader than the posterior part, and the lorica is pointed posteriorly. Several longitudinal costae are seen in the anterior part of the lorica. One flagellum is about the cell length. The cell attaches to the posterior end of the lorica by a thick stalk. Only one cell found.

Remarks: The cell observed here is assigned to Polyoeca dichotoma Kent 1880 because the observation is in agreement with those of Hara and Takahashi (1984). Polyoeca dichotoma is the only species in the genus. This species can be most readily distinguished from other species in Acanthoecidae by electron microscopy. Polyoeca dichotoma is very similar to Acanthoeca spectabilis Ellis 1929 in the length and general appearance of lorica, but according to Hara and Takahashi (1984) P. dichotoma can be distinguished by the whole length of the lorica including a long stalk. Polyoeca dichotoma is very similar to Acanthoecopsis spiculifera and due to this similarity Acanthoecopsis spiculifera Norris was synonymised with Polyoeca dichotoma Kent by Hara and Takahashi (1984). It was reported from marine habitats in Antarctica, Australia, Canada, England, France, Japan and USA ( Wailes 1929, 1939; Norris 1965; Boucaud-Camou 1967; Thomsen 1977, 1992; Buck 1980, 1981; Hara and Takahashi 1984; Tong 1997a, c; Lee 2007b).

Figures

Fig. 3. a – Petalomonas marginalis; b – Petalomonas minuta; c – Petalomonas ornata; d – Petalomonas poosilla; e–f – Ploeotia corrugata; e – general appearance of the cell from ventral and (f) dorsal view showing the ridges; g – Sphenomonas angusta; h – Ploeotia vitrea; i – Polyoeca dichotoma; j – Protaspis obliqua; k – Protaspis tegere; l – Salpingoeca marina; m – Pseudophyllomitus granulatus; n–p – ‘Aegoni’, n – postero-lateral view of the cell showing the beak – like structure; o – posterior view of the cell showing the flagellar insertions; p – general view of the cell. Scale bar: 5 μm for all figures.