Tintinnid ciliates (order Tintinnida) are a common feature of plankton communities, especially in saline and brackish-water basins. They represent a monophyletic branch of the subclass Choreotrichia entirely composed of loricate forms, that is featuring a vase-shaped shell, called a lorica, secreted by the zooid. Although it is commonly acknowledged that loricae exhibit significant intraspecific polymorphism, tintinnid ciliates are generally classified based on the overall shape and dimensions of this conspicuous structure.
In collaboration with Prof. Denis Lynn (formerly at the University of Guelph) and Dr. Michaela Strueder-Kypke (University of Guelph), I have comprehensively redescribed a peculiar tintinnid ciliate that I repeatedly found in Faro Lake during summer months, and that had been described several times with different synonyms and only based on lorica morphology. Afterwards, cooperating with Dr. Giovanni Giuffrè (University of Messina), I carried out an exhaustive study of the biogeography and ecology of this tintinnid ciliate.
The data from the latter study indicated that R. tagatzi is a neritic tintinnid ciliate, which has been reported, to date, only from the Northern Hemisphere, at tropical to warm-temperate latitudes. It has most often been detected in estuaries or lagoons characterized by a high trophic level and stable water column, and typically in the seasonal periods of highest abundance of small-sized phytoplankton (representing potential preys).
The biogeographic pattern emerging from my study demonstrates the prevalence of R. tagatzi in ports as well as in transition environments exploited for bivalve culture, confirming the former assumption of an invasive behaviour of this species, and suggesting aquaculture transplants as a possible means of dispersion for tintinnids and for ciliated protozoa in general.
Below is a planisphere showing the updated distribution of R. tagatzi. Last update: 14/0672013
In addition to the sites enumerated in my journal article: Biogeography and ecology of Rhizodomus tagatzi, a presumptive invasive tintinnid ciliate, R. tagatzi has been recently reported from the Bay of Smyrna - Turkey - by Yurga (2012), who also hypothesized ballast water as a dispersion vector for this species.