title: Improved description of the bipolar ciliate, Euplotes petzi, and definition of its basal position in the Euplotes phylogenetic tree.
abstract: Data improving the characterization of the marine Euplotes species, E. petzi Wilbert and Song, 2008, were obtained from morphological, ecological and genetic analyses of Antarctic and Arctic wild-type strains. This species is identified by a minute (mean size, 46 μm × 32 μm) and ellipsoidal cell body which is dorsally decorated with an argyrome of the double-patella type, five dorsal kineties (of which the median one contains 8-10 dikinetids), five sharp-edged longitudinal ridges, and a right anterior spur. Ventrally, it bears 10 fronto-ventral, five transverse, two caudal and two marginal cirri, 30-35 adoral membranelles, and three inconspicuous ridges. Euplotes petzi grows well at 4 °C on green algae, does not produce cysts, undergoes mating under the genetic control of a multiple mating-type system, constitutively secretes water-borne pheromones, and behaves as a psychrophilic microorganism unable to survive at >15 °C. While the α-tubulin gene sequence determination did not provide useful information on the E. petzi molecular phylogeny, the small subunit rRNA (SSU rRNA) gene sequence determination provided solid evidence that E. petzi clusters with E. sinicus Jiang et al., 2010a, into a clade which represents the deepest branch at the base of the Euplotes phylogentic tree.
authors: Department of Biology, University of Pisa, 56126 Pisa, Italy.
authors: Graziano
authors: G
authors: Di Giuseppe
authors: Department of Biology, University of Pisa, 56126 Pisa, Italy.
authors: Fabrizio
authors: F
authors: Erra
authors: Department of Biology, University of Pisa, 56126 Pisa, Italy.
authors: Francesco
authors: F
authors: Paolo Frontini
authors: Department of Biology, University of Pisa, 56126 Pisa, Italy.
authors: Fernando
authors: F
authors: Dini
authors: Laboratory of Eukaryotic Microbiology and Animal Biology, University of Camerino, 62032 Camerino, MC, Italy.
authors: Adriana
authors: A
authors: Vallesi
authors: Laboratory of Eukaryotic Microbiology and Animal Biology, University of Camerino, 62032 Camerino, MC, Italy. Electronic address: piero.luporini@unicam.it.
authors: Pierangelo
authors: P
authors: Luporini
mesh_terms: D046508:Culture Techniques; D016812:Euplotes / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D013045:Species Specificity; D013696:Temperature; D014404:Tubulin / Q000235:genetics
chemical_list: D012337:RNA, Ribosomal, 18S; D014404:Tubulin
keywords: Bipolar species; Ciliate taxonomy and phylogeny; Marine microfauna; Polar microorganisms; SSU rRNA gene sequences