Gemmata obscuriglobus is a species of Gram-negative, aerobic, heterotrophic bacteria of the phylum Planctomycetes. G. obscuriglobus occur in freshwater habitats and was first described in 1984, and is the only described species in its genus. G. obscuriglobus is exceptional for its unusual morphology and for the unusual features in its genome, often considered to represent large differences in internal organization compared with most prokaryotes