Description: Cells biradiate, small; semicells horizontally rectangular. There is a single large divergent spine emanating from each apical corner. Apical margin straight or very slightly convex, basal angles rounded forming a long cylindrical isthmus. Sinus a large U-shape. Cell wall smooth or finely punctate. End view narrowly elliptic with a single spine from narrow ends. Side view sub-circular with a single spine from each end. Single pyrenoid in each semicell. Length ssp. 22.0–25.1um, lenght csp. 38.1–49.3um, Breadth ssp. 21.7–28.3um, Breadth csp. 41.3–52.5um, Isthmus 5.3–6.5um, Thickness 7.7–8.6um. (Dingley 2001)

State distribution in Australia, based on available literature

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