Protaspis (pro-tass-piss) obliqua Larsen and Patterson, 1990. Cells are slightly oval or roundish, 8 to 32 microns long, 10 to 27 microns wide, dorso-ventrally flattened and with thickened cortex. There is a ventral median groove, cell indented anteriorly and posteriorly where the groove meets margin. Subapically, the right margin of the groove forms a protrusion. With two flagella inserting under the protrusion, the anterior flagellum is about 0.5 times the length of the cell and the posterior flagellum is about 0.5 to 1.5 times the length of the cell. The nucleus is without nuclear caps, is located subapically in a median position, is rounded and is 5 to 13 microns in diameter. The cells may contain food particles or diatom up to 24 microns long. Commonly observed.
Protaspis obliqua Skuja, 1939. Cells are slightly oval or roundish, 8 to 32 microns long, 10 to 27 microns wide, dorso-ventrally flattened and with thickened cortex. There is a ventral median groove, cell indented anteriorly and posteriorly where the groove meets margin. Subapically, the right margin of the groove forms a protrusion. With two flagella inserting under the protrusion, the anterior flagellum is about 0.5 times the length of the cell and the posterior flagellum is about 0.5 to 1.5 times the length of the cell. The nucleus is without nuclear caps, is located subapically in a median position, is rounded and is 5 to 13 microns in diameter. The cells may contain food particles or diatom up to 24 microns long.
