Symbiont in Hippospongia sp. a) TEM analysis for Hippospongia sp. showing cyanobacterial symbionts belonging to the "Candidatus Synechococcus spongiarum" clade as single cells and during division (bf = binary fission), scale bar = 1 μm. b) TEM showing two symbionts with thylakoid spirals (indicated by arrow), scale bar = 200 nm.
Lemloh et al. BMC Ecology 2009 9:4 doi:10.1186/1472-6785-9-4