Phylogenetic Relationships within the Class Spirotrichea (Ciliophora) Inferred from Small Subunit rRNA Gene Sequences

Comparative phylogenetic study of Stichotrichia (Alveolata: Ciliophora: Spirotrichea) based on 18S-rDNA sequences

“…This group is often recovered in molecular phylogenies (e.g., Bernhard et al, 2001;Hewitt et al, 2003;Foissner et al, 2004;Schmidt et al, 2007;Shao et al, 2007;Yi et al, 2008a,b) and so they were in both our trees, however, with discrepant placement of Steinia sphagnicola and Sterkiella histriomuscorum. Nevertheless, stylonychine external affinities did not follow the same pattern in both trees.…”

“…During the last years, attempts to hypothesize the evolutionary relationships among the Stichotrichia (= Hypotricha in Berger, 2006) and closely related groups based on molecular data (e.g., Bernhard et al, 2001;Hewitt et al, 2003;Strüder-Kypke and Lynn, 2003;Foissner et al, 2004;Foissner and Stoeck, 2006) have given results that generally contradict other hypotheses and classification systems based on morphological data (e.g., de Puytorac et al, 1994;Berger and Foissner, 1997;Eigner, 1997Eigner, , 1999Eigner, , 2001Lynn and Small, 2002;Lynn, 2003;Agatha, 2004;Foissner et al, 2007).…”

“…The most remarkable are: i) the placement of Halteria grandinella among the flexible-body oxytrichids (Bernhard et al, 2001;Strüder-Kypke and Lynn, 2003), referred to as the "Halteria paradox" (see Foissner et al, 2007); ii) the separation of Uroleptus from the urostylids (Croft et al, 2003;Hewitt et al, 2003;Foissner et al, 2004;Stoeck, 2006, 2008), which led to the "Convergent Evolution of Urostylids and Uroleptids" (CEUU) hypothesis, and the polyphyly of the non-uroleptid urostylids, suggested in subsequent studies (Schmidt et al, 2007;Yi et al, 2008a,b); iii) the polyphyly of Oxytricha (Schmidt et al, 2007), and iv) the splitting of the Stichotrichia, which were polyphyletic in Yi et al (2008b).…”

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

“…taxa such as Stylonychia (14), more than 60 nucleotide mutations have been found in SSU-rRNA gene sequence comparisons between E. nobilii and Euplotes raikovi, which is a temperate water species that is phylogenetically closely related to E. nobilii (15). In light of this situation, we interpret the one-to four-nucleotide substitutions detected among the SSU-rRNA gene sequences of the E. nobilii strains as reflecting sequence variations that are merely intraspecific, and not indicative of interstrain divergences of phylogenetic significance.…”

Large-scale phylogenomic analysis reveals the phylogenetic position of the problematic taxon Protocruzia and unravels the deep phylogenetic affinities of the ciliate lineages

“…Beyond this deep division, it is generally agreed that there are 11 major ciliate lineages or classes and a twelfth single species clade of Cariacotrichea (Adl et al, 2012;Lynn, 2008;Orsi et al, 2012;Stoeck et al, 2003). Most of these classes are strongly supported by morphology, with the exception of the ''riboclasses'' -the Armophorea and Plagiopylea, which are identified only by sequences of the 18S rRNA genes, as included taxa lack any morphological synapomorphies (Bernhard et al, 1995(Bernhard et al, , 2001Cameron et al, 2001;Embley et al, 1995;Greenwood et al, 1991;Leipe et al, 1994;Lynn, 2008;Lynn et al, 1999;Lynn and Strüder-Kypke, 2002;Snoeyenbos-West et al, 2004;Stechmann et al, 1998). Nevertheless, the monophyly of the class Spirotrichea has been challenged in several studies, notably those that include Protocruzia spp.…”