title: Phylogenetic relationships of the ciliate class Heterotrichea (Protista, Ciliophora, Postciliodesmatophora) inferred from multiple molecular markers and multifaceted analysis strategy.
abstract: The ciliate class Heterotrichea is defined by somatic dikinetids bearing postciliodesmata, by an oral apparatus consisting of a paroral membrane and an adoral zone of membranelles, as well as by features of nuclear division involving extramacronuclear microtubules. Although phylogenetic interrelationships among heterotrichs have been analyzed several times, deeper nodes of the heterotrichean tree of life remain poorly resolved. To cast more light on the evolutionary history of heterotricheans, we performed phylogenetic analyses of multiple loci (18S rRNA gene, ITS1-5.8S rRNA-ITS2 region, and 28S rRNA gene) using traditional tree-building phylogenetic methods and statistical tree topology tests as well as phylogenetic networks, split spectrum analysis and quartet likelihood mapping. This multifaceted approach has shown that (1) Peritromus is very likely an adelphotaxon of all other heterotrichs; (2) Spirostomum and Anigsteinia are sister taxa and their common monophyletic origin is strongly supported by a uniquely posteriorly-thickened paroral membrane; (3) the monotypic family Chattonidiidae should be suppressed because its type genus clusters within the family Condylostomatidae; and (4) new families are needed for Gruberia and Fabrea because their affiliation with Spirostomidae and Climacostomidae, respectively, is not supported by molecular phylogenies nor the fine structure of the paroral membrane.
authors.affiliation: Department of Biological Science, University of Ulsan, Ulsan 680-749, South Korea.
authors.forename: Shahed Uddin Ahmed
authors.initials: SU
authors.lastname: Shazib
authors.affiliation: Department of Zoology, Comenius University, 84215 Bratislava, Slovakia. Electronic address: vdacny@fns.uniba.sk.
authors.forename: Peter
authors.initials: P
authors.lastname: Vd'ačný
authors.affiliation: Department of Biological Science, University of Ulsan, Ulsan 680-749, South Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Biological Science, University of Ulsan, Ulsan 680-749, South Korea.
authors.forename: Seok Won
authors.initials: SW
authors.lastname: Jang
authors.affiliation: Department of Biological Science, University of Ulsan, Ulsan 680-749, South Korea. Electronic address: mkshin@ulsan.ac.kr.
authors.forename: Mann Kyoon
authors.initials: MK
authors.lastname: Shin
mesh_terms: D016798:Ciliophora / Q000145:classification* / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry; D020459:Genes, rRNA; D005819:Genetic Markers; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D021903:DNA, Ribosomal Spacer; D005819:Genetic Markers; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S
keywords: 18S rRNA gene; Fabreidae fam. n.; Gruberiidae fam. n.; ITS1-5.8S rRNA-ITS2 region