The part of a valve that extends from the valve face, forming the edge of the valve. When a frustule is viewed in girdle view, the mantle is visible.
Taxa that possess a raphe on only one valve are considered within the monoraphid group. Freshwater monoraphid genera include Cocconeis, Achananthes, Achnanthidium, Eucocconeis, Karayevia, Lemnicola, Planothidium, Platessa, Psammothidium and Rossithidium. The genus Nupela includes some monoraphid species and some biraphid species. On the Diatoms of the US website, Nupela is included in the biraphid group.
A monotypic genus is one for which a single binomial is validly published. An example of a monotypic genus is Diprora Main. The genus contains only one species, Diprora haenaensis Main.
Mucopolysaccharide secreted by diatoms