15th INTERNATIONAL CONGRESS OF PROTISTOLOGY (ICOP)  30th July – 4th August 2017 Prague, Czech Republic.

I presented a paper on this new species and my abstract is below.


ID: 61
Topic: Diversity of free-living heterotrophic protists

A new species of folliculinid bearing endosymbiotic dinoflagellates

John Stuart Douglas (University of Adelaide South Australia, Adelaide, Australia), David J. Patterson (Sydney University, Sydney, Australia), Ryan O’Handley (University of Adelaide, Adelaide, Australia), Tracy Ainsworth (James Cook University, Townsville, Australia), Agatha Labrindis (Adelaide Microscopy, University of Adelaide, Adelaide, Australia)

A previously undescribed folliculinid has been found in the temperate near shore coastal sea-grass beds of the Gulf Saint Vincent South Australia. It contains endosymbiotic dinoflagellates. Such dinoflagellates are found in coral hydroids, in Foraminifera, radiolaria and heterotrich ciliates. This is the first record of a Symbiodinium-like organism being found in the Folliculinidae. The trophont of the folliculinid contains between 500–600 dinoflagellate cells and 150–300 in its swarmers. Mulisch (1987) suggested that the Folliculinidae evolved from the ancestors of recent Stentoridae (i.e. Stentor). More recent DNA studies propose that Stentor spp. are more closely related to Blepharisma, while it is Maristentor that is closest to folliculinids. Folliculinids are almost exclusively marine, as is Maristentor dinoferus, both tend to cluster and both have pigmented granules in the cortex. The folliculinid was collected from a number of sites and was always attached to Zostera or Amphibolis sea-grass. Collections of sea-grass with the ciliates were placed in dishes of filtered sea water to remove any planktonic dinoflagellates. Two generations of trophonts and swarmers were cultured, all contained symbionts. This paper presents the results of detailed taxonomic and genomic studies of this new species, and explores the phylogenetic connections between folliculinid protists, coral hydroids and endosymbiotic dinoflagellates.

Keywords:  Symbiodinium, New species of Folliculinidae

April 6th 2017: The FIRST RECORD of a “Symbiodidium” endosymbiont within a new species of folliculinid protist.

Samples of the sea-grass Amphbibolis were collected 1km off-shore of Wool Bay, South Australia. Numerous folliculinids were attached to amphibolis. On closer examination the folliculinids had what appeared to be endosymbiotic algae. Extensive examination using DIC, transmission and dark field  microscopy, revealed what appeared to be symbiodinia, a genera of dinoflagellate found in coral hydroids, some foraminifera, radiolarians and a few other protists. They have never been recorded in Folliculinids.  Further inspections, and communications with Dr Tracy Ainsworth of James Cook University suggested that they are symbiodidia. Plate 1 illustrates Amphibolis antarctica, plate 2 is a folliculinid within its lorica, showing the peristomal wings and hundreds of “symbiodina”. Over 30 folliculinids were imaged, measured and all confirmed this symbiotic relationship.

April 15th 2017: Abundant numbers of the same Folliculinid species were collected at other sites near Edithburgh 10km south of Wool Bay, this time on Zostera sea-grass. “Symbiodinia” were found in all trophonts, in a dish over several days swarmers appeared and all were full of symbionts.

MAY 2017 DNA SEQUENCING: samples have been sent to Dr Tracy Ainsworth at the ARC Centre of Excellence on Coral for DNA sequencing, unfortunately these were not processed correctly. Further sequencing will be carried out in 2018 at the School of Animal and Vet Science, The University of Adelaide.

Plate1: Amphibolis antarctica.

Plate 2: Folliculina sp with “symbiodinia”.

Symbiodinia are the symbiotic algae found in coral reef hydroids. What interests me is why are they residing inside a folliculinid protozoa in the cool temperate waters of southern Australia? This also raises questions regarding the co-evolution of symbiodinia in single celled protists and metazoan coral hydroids.

I am presenting a paper on this new species at the 15th-International Congress Of Protistology (ISCOP) in Prague, July 29th – 4th August 2017.

The following images are part of a extensive measurement process of the endosymbionts within the trophonts and swarmers.

PLATE 3: Young trophont with measurements of symbiodidia.

PLATE 4: Swarmer with symbiodidia and measurements.

PLATE 5: Isolated symbiodidia with measurements.