| We present large subunit (LSU) and internal transcribed spacer (ITS) rDNA based phylogenies of symbiotic dinoflagellates retrieved from single-cell planktonic foraminifera collected around the world. All modern foraminiferal species involved in such symbiosis are included in our analyses. The pelagic symbiotic dinoflagellates form a monophyletic group sister to the Symbiodinium species complex found in coastal-benthic environments. The pelagic symbionts are descendants of free-living species and, together with the coastal-benthic Symbiodinium spp., they originated from the early Mesozoic suessiacean family represented by the extant Polarella glacialis. Out of hundreds of single planktonic foraminifera examined, 21 unique pelagic symbiont ribotypes were... |
