Symbiodinium dinoflagellates in soritid Foraminiferans

We have applied various molecular phylogenetic approaches on the symbionts of soritids foraminifera (sub-family Soritinae) to reveal an extraordinary diversity of Symbiodinium lineages, most of which were specifically associated with this relatively small group of foraminifera. In order to investigate this surprising finding, we have produced a number of ecological and evolutionary studies to show that:

1. The specificity between soritids and Symbiodinium is greater than previously thought and can also be found at a lower taxonomic level within Soritinae
2. The diversity of soritid-specific symbionts is much greater in the Indo-Pacific than in Western Atlantic, hence correlates positively with the distribution of soritid diversity
3. The eight existing lineages in the genus Symbiodinium may have originated in early Eocene, the majority of which diversified since mid-Miocene, about 15 million years ago
4. The high specificity between Soritinae and their symbionts is the consequence of associational drift resulting from a dominating vertical transmission of symbionts during the soritid asexual reproduction

people working on this subject: Xavier POCHON, Jan Wojciech PAWLOWSKI.