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Guide to Aulacoseira nivaloides

(Camburn) English and Potapova 2009

Aulacoseira Nivaloides Guide
Credit: Jonathan English, Marina Potapova
  1. Ratio of mantle height to valve diameter < 1
  2. Rows of mantle areolae straight, inclined to the right
  3. Valve face convex or concave
  4. Valve face covered by areolae
  5. Spines originate from every second or third costa

Valves are 4-11 µm in diameter, with a mantle height of 4-7 µm. The ratio of the mantle height to valve diameter is close to 1. The valve face is convex or concave, covered by areolae. Rows of pervalvar areolae are straight or slightly inclined to the right, 14-22 in 10 µm, with 13-21 areolae in 10 μm. The height of the collum is approximately 1/3 of the mantle height. The pointed spines originate from every second or third costa. The ringleiste is very shallow.