Placosphaera opaca Dangeard

Kim, Yong Jae, 2017, New records of coccoid green algae in Korea, Journal of Species Research 6 (1), pp. 42-50 : 45

Placosphaera opaca Dangeard ( Fig. 2 i-k)

References: Komárek and Fott 1983: 606, pl. 170, fig. 3; Showalter 1952: 113, fig. 1.

Occurrence site: Chukdong reservoir (WT 28.3℃, pH 8.3. EC 213 μs/cm).

Description: This species is unicellular, nonmotile, and spherical to slightly tetrahedral or elliptical in shape. The cell wall appears to radiate, and has a thick layer of platelet-like calcite crystals imbedded in a gelatinous sheath. A chloroplast located in center of the cell contains a pyrenoid. The cells are 20-30 μm in diameter.

Distribution: Caen, France ( Dangeard, 1889), Muskrat swamp and Lake View, Kansas ( Showalter, 1952), India ( Komárek and Fott, 1983).

Specimen: NIBRCL0000112293; DAEJIN-20150603-3.

Remark: This species was first described from a swamp in Caen, France by Dangeard (1889). Showalter (1952) also collected this species from filamentous algae and other submerged or floating aquatic plants in lakes and ponds in Kansas, USA (not from the plankton). In the present study it was collected in plankton nets at shallow depths off the shore of Chukdong reservoir. This species was included in the family Chlorellaceae , order Chlorococcales , class Chlorophyceae by Komárek and Fott (1983), but Guiry and Guiry (2016) placed it in the family Tetrasporaceae , order Chlamydomonadales in the class Chlorophyceae. In this study it is classified according to Komárek and Fott (1983).

Figures

Fig. 2. a-c. Fotterella tetrachlorelloides, d, e. Trochiscia naumannii, f-h. Keriochlamys styriaca, i-k. Placosphaera opaca. Scale bar is 10μm.