Eunotia spatulata

Valves are straight, narrowing very gradually and slightly from the center to the subapical portion, from which the valves widen abruptly into the widely spatulate apices (Figs 104–117), 159–272 μm long, 3.3–4.0 μm wide in center, 1.9–2.8 μm wide in narrowest part, 5.3–6.4 μm wide at apices. The apices are inflated more on the dorsal side than the ventral side and appear flattened at the ends (Figs 104–117). The valve edges are sharply beveled with one to two rows or areolae in the beveled section (Figs 120, 121, 124). Irregularly arranged siliceous ridges are present at the apical margins of the valves (Figs 119, 121–123). Raphe begins on the valve mantle, and curves subapically on the valve face back towards the main part of the valve. It is centered with respect to the main axis of the valve but closer to the ventral margin because of the unevenly widened apices (Figs 119, 121–123). External raphe fissure is visible on the external portion of the valve (e.g., Fig. 122), but does not penetrate the internal part of valve past the helictoglossa, where it is internally occluded by a hyaline linear area interrupting the striae past the helictoglossa (Figs 126, 127, 130, 131). A single rimoportula is present on each valve, and is located within the apical edge adjacent to the helictoglossa (Figs 122, 123, 127, 129), usually visible in the LM (Figs 104b, 105b, 107b). Striae are fine and parallel throughout the valve, including the apices, where they are spaced more densely (Figs 126–133), 18–21 in 10 μm, up to 23.5 in 10 μm at the ends. Areolae are circular and externally occluded (Fig. 122), 33–40 in 10 μm.

• Author
  J.Veselá and J.R.Johans. 2014
• Length Range
  159–272 µm
• Width
  3.3–4.0 μm in the center, at apices 5.3–6.4 µm
• Striae in 10µm
  18–21