Isoprenoid glycerol dialkanol diethers: A series of novel archaeal lipids in marine sediments

► Isoprenoid glycerol dialkanol diethers (GDDs) are widespread in marine sediments. ► They co-occur with corresponding GDGTs. ► Recycling of fossil GDGTs by benthic archaea may produce GDDs. ► GDDs were also found in an archaeal culture, suggestive of a biological origin.