Endosymbiotic heterocystous cyanobacteria synthesize different heterocyst glycolipids than free-living heterocystous cyanobacteria

► Glycolipids rarely investigated for marine heterocystous cyanobacteria. ► Glycolipids of selected marine cyanobacteria were similar to that of freshwater representatives. ► Heterocystous endosymbionts found in diatoms synthesize different glycolipids. ► These glycolipids contain C5 sugars and longer chain lengths for the aglycone moiety.