Psammodictyon crassum sp. nov., a new diatom species from the coastal waters of Viet Nam based on morphology and molecular data

Abstract

Psammodictyon is a small genus of predominantly marine diatoms. A new species of Psammodictyon, P. crassum sp. nov., is described from the South China Sea (Viet Nam) based on light and scanning electron microscopical observations and molecular data for the V4 18S rRNA and rbcL regions. Morphologically, P. crassum sp. nov. is most similar to the freshwater P. taihuensis Q. Yang, Q.-M. You & Q. X. Wang differ in longer and wider valves with a hyaline sternum along the longitudinal fold. Morphological differences between P. crassum and other taxa are discussed. Molecular data support species separation; the retrieved rbcL and V4 18S rRNA sequences are unique.