Cosmopolitan metapopulations?

A “metapopulation” is a group of populations of the same species separated by space but linked by dispersal and migration. Metapopulations of macroscopic organisms tend to have geographically-restricted distributions, but this does not seem to be the case in microbial eukaryotes due to their astronomical abundance. The term “metapopulation” was first applied to protists’ biogeography in the article Finlay and Fenchel (2004), published in PROTIST, which contributed to the popularity of the paper. The article considered protist species as consisting of a single, cosmopolitan population. Here, we recall this paper, and assess developments during the last 15 years with respect to the question of protist species distribution on the surface of the earth

First Records of ‘Flagship’ Soil Ciliates in North America

‘Flagship’ ciliates were investigated from soil samples collected in Florida, USA. This was undertaken to determine if species thought to be restricted to a given world region could be uncovered from similar habitats in a novel location, e.g. another continent. Two species of Condylostomides were discovered, and recorded from the North American continent for the first time. Condylostomides etoschensis was known only from Africa, but was found to be thriving in a Florida study site. An 18S rDNA sequence for this species was determined for the first time. Also discovered from the same study site was the ciliate Condylostomides coeruleus, previously known only from Central and South America. These two ‘flagship’ ciliates were found in the same habitat, from a continent well outside of their previously recorded biogeographies. Molecular sequencing and microscopy investigations were conducted to form the baseline for future work within this genus. Soil ciliates can obtain large population numbers and form cysts and are therefore likely able to disperse globally. These new records provide additional evidence that large distances, even between continents, do not hinder microbes from thriving globally. The absence of these conspicuously-colored gold and blue ciliates from previous studies is likely due to undersampling, rather than to any physical barriers