title: Morphology and 18S rDNA phylogeny of Hemicycliostyla sphagni (Ciliophora, Hypotricha) from Brazil with redefinition of the genus Hemicycliostyla.
abstract: Morphology of the urostylid ciliate Hemicycliostyla sphagni Stokes, 1886, the type of Hemicycliostyla Stokes, 1886, is investigated based on live and protargol-impregnated specimens from a Brazilian population. The absence of transverse cirri, which has been considered the main diagnostic feature of Hemicycliostyla, separating it from Pseudourostyla Borror, 1972, was found to vary within the studied population, with 50% of the specimens exhibiting inconspicuous and/or rudimentary transverse cirri. A redefinition of Hemicycliostyla was possible based on combined features of interphase and divisional morphogenesis: Retroextendia Berger, 2006, with bi- or multicoronal frontal cirral pattern; fronto-terminal cirri present; multiple left and right marginal cirral rows that replicate independently via within-row development, each parental row producing one primordium per divider; caudal cirri lacking; and presence/absence of transverse cirri may be intrapopulationally variable. Phylogenetic analyses of the 18S rDNA marker unambiguously placed H. sphagni as sister group of Pseudourostyla franzi Foissner, 1987, which is herein transferred to Hemicycliostyla as Hemicycliostyla franzi comb. nov.
authors.affiliation: Laboratório de Protistologia, Departamento de Zoologia, Instituto de Biologia, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro - RJ, Brazil.
authors.forename: Thiago da Silva
authors.initials: TDS
authors.lastname: Paiva
authors.affiliation: Instituto Socioambiental e dos Recursos Hídricos, Universidade Federal Rural da Amazônia, Belém - PA, Brazil.
authors.forename: Bárbara do Nascimento
authors.initials: BDN
authors.lastname: Borges
authors.affiliation: Laboratório de Protistologia, Departamento de Zoologia, Instituto de Biologia, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro - RJ, Brazil.
authors.forename: Inácio Domingos da
authors.initials: IDD
authors.lastname: Silva-Neto
authors.affiliation: Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Cidade Universitária Prof. José Silveira Netto, Universidade Federal do Pará, Belém - PA, Brazil.
authors.forename: Maria Lúcia
authors.initials: ML
authors.lastname: Harada
mesh_terms: D001938:Brazil; D016798:Ciliophora / Q000145:classification / Q000166:cytology* / Q000235:genetics*; D016000:Cluster Analysis; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D010802:Phylogeny; D016053:RNA, Protozoan / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D016053:RNA, Protozoan; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S