Evolutionary history of the genus <i>Euplotes</i>.

<p>Phylogenetic relationships are based on recent SSU rRNA gene analyses (see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0165442#pone.0165442.g003" target="_blank">Fig 3</a>). Colors on branches represent habitats, according to sequence metadata and literature. The 38 morphospecies included were grouped in 15 monophyletic subclades. When species within a subclade did not all share the same environment (see text), majority-rule consensus was applied. Schematic drawings represent the dorsal argyrome type(s) and frontoventral cirral pattern(s) of the species in each subclade (the argyrome type of <i>E</i>. <i>dammamensis</i> is unknown). Dimensions of the drawings correlate with the average size of the species. The character status of ancestors was inferred using a parsimony criterion. Changes in the argyrome type (green) or the number of frontoventral cirri (red) are shown on branches. Intra-subclade variability is highlighted with colored boxes: red-shaded cirri were lost and green-shaded dargyrome types were acquired by the marked species. The establishment of the obligate symbiosis between <i>Euplotes</i> species and the betaproteobacterium <i>Polynucleobacter</i> is also shown.</p>