Ciliated protists represent one of the most primitive lineages of eukaryotes, with nuclear dimorphism, a distinctive sexual process (conjugation), and extensive genome rearrangements. Sessilida, among diverse ciliate lineages, is the only group containing members living a colonial lifestyle, i.e., many cells are ‘connected’ by their stalk and a colony is formed through binary fission.
Click here for original story, New insights into the evolutionary phylogeny of the ciliate order Sessilida
Source: Phys.org