| Frustule | Light to moderately silicified – | – | – | – |
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| Shape | Linear-elliptic, linear- lanceolate | – | – | – |
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| Raphe | Straight and filiform | Linear to weakly curved | – | Slightly deflected and curved |
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| Umbilicus | Kink-like irregularity closer to valve apices along the raphe fissure | Absent | – | – |
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| Terminal raphe fissure | Hooks on the valve face, does not continue onto the mantle | Bends in the same direction and extends to the mantle | – | Terminates in a long helictoglossa |
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| Areolae | – | Large and round, covered externally by a multiseriate hymen and a silica layer at the outer periphery of each areola | Elliptical in outline, externally covered with a hymen | Presence of hymen that obscures small areolae details |
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| Striae | Alveolae-like apertures with – recessed pores, arranged radially at the mid-valve changing to convergent at the Voigt fault and then extending to the apices | – | – | – |
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| Internal structure | Narrow raised sternum, – straight or T-shaped proximal ends of the raphe, small raised helictoglossa at the distal end | – | – | Central raphe ends deflected, terminal raphe fissure terminates in a long helictoglossa |
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| Genetic affiliation | – | Distant from Kobayasiella, aligned with Geissleria and Placoneis | Chloroplast genetic affinity to Pinnularia and Stauroneis | Genetically associated with Eolimna |
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