New and interesting diatoms from the Shimen Wetwalls, Yunnan Province, China. II. The diatom genus Nupela Vyverman & Compère (Bacillariophyceae)

We detailed the valve morphology of five new species of diatom genus Nupela from wetwall communities in Yunnan Province, China, with light and scanning electron microscope. The five new species demonstrate great variability within the genus, as three of them are biraphid and two are monoraphid. In addition, variation was noted in the structure of internal proximal raphe ends, with some species having anchor-shaped ends and other species have hooked ends. The genus Nupela has grown considerably in 30 years since it was first proposed, going from a monotypic genus to over 85 taxa. Diagnosis of the genus is based on the presence of an external covering over the areolae. We discussed the systematic placement of Nupela within the naviculoid diatoms. Yunnan Province appears to harbor many endemic diatom taxa, and many regions of the province have yet to be studied.