Molecular Phylogeny Of Oligotrichs And Other Four Important Marine Ciliate Groups

We focused on the molecular phylogeny study of five groups, karyorelictids, haptorids, cyrtophorids, peniculines, and oligotrichs (+choreotrichs). The small subunit ribosomal RNA genes for more than 50 species have been amplified and submitted to the GenBank database. Five methods were used for phylogenetic tree construction, namely Bayesian interference, maximum likelihood, maximum parsimony, neighbor-joining, and least-squares. We1) Proposed for the first time that several well-outlined monophyletic assembledges are genetically diverse (paraphyletic/polyphyletic): 2 genera (Frontonia, Strombidium), and 2 orders (Chlamydodontida, Loxodida).2) Provided molecular evidence for the separation of 5 genera: Parduczia, Trachelotractus, Siroloxophyllum, Spirostrombidium, Parallelostrombidium.3) Analyzed the inter-generic relationship of the most ancient group - Karyorelictea. Amplified the small subunit ribosomal RNA genes for two species in the family Kentrophoridae, whose systematic position has been controversial for a long time. Combining its molecular nformation, the unique morphological and ecological characters of this group, we suggested raising the family Kentrophoridae to the ordinal level.4) Collected the small subunit ribosomal RNA genes for 18 species in the Class Phyllopharyngea, 15 of which had no molecular information so far. Microxysma, which was designated to the family Hartmannulidae by all taxonomic schemes, should be transferred to family Dysteriidae based on its morphological and molecular information. 5) Three Group I introns were discovered in the SSU rRNA gene of Aegyriana oliva, which becomes the 4th ciliate species with reported Group I intron. More importantly, Aol.S516 is the first intron at position 516 (according to the SSU rRNA gene of E. coli), and the only one belonging to the IE subgroup.6) Investigated the phylogenetic positions of 12 species in the Subclasses Oligotrichia and Choreotrichia. We suggested that the strombidiid Laboea should be transferred to the family Tontoniidae. The sinistrally spiraled girdle kinety shared by Laboea and tintiniids is likely a synapomorphy rather than a convergent feature as previously speculated.