Abstract
A new species of tropical marine cyanobacterium was isolated from the coast of Singapore. Lyngbya regalis is a filamentous, non-heterocystous cyanobacterium that forms a brown-green macroscopic thallus of filaments that are straight to wavy. Filaments are enclosed in a transparent, lamellated sheath with distinct cross-wall constrictions observed and apical cells that are widely rounded. The combined phenotypic, phylogenetic (16S rRNA sequences) and ecological characteristics observed indicate that Lyngbya regalis is a novel species within the genus Lyngbya C. Agardh ex Gomont.