Diversity of the genus Orthoseira Thwaites (Bacillariophyceae) from Southeast Asia and Rapa Nui Island with descriptions of four new taxa

The genus Orthoseira Thwaites contains centric diatoms typically inhabiting marginal-aquatic or terrestrial habitats. The high morphological plasticity of representatives of the genus and their occurrence in rarely studied terrestrial habitats complicates an overall assessment of their biodiversity and the distribution of particular species. This study presents a description of four new species of this genus from Southeast Asia and Easter Island. They include: O. radiata M.Rybak, Glushchenko & Kulikovskiy sp. nov., O. distincteareolata M.Rybak, Glushchenko & Kulikovskiy sp. nov., O. cylindrica M.Rybak, Glushchenko & Kulikovskiy sp. nov. and Orthoseira rapanuiensis M.Rybak, Witkowski & Lange-Bertalot sp. nov. Additionally, we attempt to provide a solution to the confused taxonomical history of Liparogyra circularis Ehrenberg and provide the first detailed description of Orthoseira tropica (Krasske) Metzeltin & Lange-Bertalot.

Automated summary

This study describes four new species of the genus Orthoseira from Southeast Asia and Easter Island, as well as provides a solution to the taxonomical history of Liparogyra circularis Ehrenberg and a detailed description of Orthoseira tropica (Krasske) Metzeltin & Lange-Bertalot.