Gonatozygon monotaenium

The genus Gonatozygon belongs to a separate family of placoderm desmids (Fam. Gonatozygaceae). Cells are elongate and but little desmid-like as a distinct median constriction is wanting and semicell morphology is most simple. Cells of Gonatozygon monotaenium are elongate-cylindric and characterized by a finely granulate cell wall. In the Netherlands G. monotaenium is rather common in mesotrophic, slightly acidic or circumneutral water bodies. Zygospore formation, on the contrary, is very rare.

Image © Henk Schulp

Cell of Gonatozygon monotaenium. Notice the minutely granular cell wall and the slightly dilated apices marked by acutely rounded angles.

Cell dimensions (L x B): ca 200 x 10 µm

 

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Conjugated cells of G. monotaenium with a globular, smooth-walled zygospore in between.

Image © Henk Schulp