Abstract
A new brackish water urostylid ciliate, Pseudourostyla cristatoides n. sp. was collected from Songjiho lagoon on the coast ofEast Sea, South Korea, and investigated based on morphology, morphogenesis, and 18S rRNA gene sequences.Pseudourostyla cristatoides is characterized by the following features: slender to elliptical body shape; colourless to dark greyin colour; size in vivo about 220–265 × 85–125μm; flexible and slightly contractile body with narrowly spaced extrusomes(trichocyst type) throughout the whole cell; 2 contractile vacuoles on left side of cell at about 25% and 75% of body length;84–115 adoral membranelles, 20–30 frontal cirri, 1 buccal cirrus, 2 frontoterminal cirri, 17–25 midventral pairs, 2pretransverse, 6–12 transverse cirri, 5–7 left and 4–5 right marginal rows, and 10–13 dorsal kineties; 30–106 macronuclearnodules and 3–5 micronuclei; brackish habitat (salinity 3–5‰). This new species is very similar to P. cristata, but distinguishedprimarily by contractile vacuoles (2 vs. 1 in number; positioned 25%, 75% of body length vs. ahead of mid-body), dorsalkineties (10–13 vs. 8), hyaline layer underneath pellicle (inconspicuous vs. conspicuous), habitat (brackish vs. freshwater), andparticipation of posterior cirri of rear corona in fronto-ventral-transverse cirral anlagen (yes vs. no). Additionally, intra-/inter-specific pairwise genetic distances of the 18S rRNA gene sequences supported that the Songjiho population is a novel species(intra-specific distances of 0.07–0.12% among three P. cristata populations vs. inter-specific distances of 0.93–1.00% between P. cristatoides and three P. cristata populations).References
Berger, H. (2006) Monograph of the Urostyloidea (Ciliophora, Hypotricha). Monographiae biologicae, 85, i–xv, 1–1303.
Borror, A.C. (1972) Revision of the order Hypotrichida (Ciliophora, Protozoa). Journal of Protozoology, 19, 1–23.
Chen, X., Li, Z., Hu, X. & Kusuoka, Y. (2010) Morphology, morphogenesis and gene sequence of a freshwater ciliate, Pseudourostyla cristata (Ciliophora, Urostyloidea) from the ancient Lake Biwa, Japan. European Journal of Protistology, 46, 43–60.
Foissner, W. (1991) Basic light and scanning electron microscopic methods for taxonomic studies of ciliated protozoa. European Journal of Protistology, 27, 313–330.
Grim, J.N. & Manganaro, C.A. (1985) Form of the extrusomes and secreted material of the ciliated protozoon Pseudourostyla cristata, with some phylogenetic interpretations: a light, scanning electron, and transmission electron microscopic study. Transactions of the American Microscopical Society, 104, 350–359.
Grinienė, E., Mažeikaitė, S. & Gasiūnaitė, Z. (2011) Inventory of the taxonomical composition of the plankton ciliates in the Curonian Lagoon (SE Baltic Sea). Oceanological and Hydrobiological Studies, 40, 86–95.
Guindon, S. & Gascuel, O. (2003) A simple, fast, and accurate algorithm to estimate large phylogenies by maximum likelihood. Systematic Biology, 52, 696–704.
Hall, T. (1999) BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symposium Series, 41, 95–98.
Jeanmougin, F., Thompson, J.D., Gouy, M., Higgins, D.G. & Gibson, T.J. (1998) Multiple sequence alignment with Clustal X. Trends in Biochemical Sciences, 23, 403–405.
Jerka-Dziadosz, M. (1964) Urostyla cristata sp. n. (Urostylidae, Hypotrichida): the morphology and morphogenesis. Acta Protozoologica, 2, 123–128, Plates I, II.
Jerka-Dziadosz, M. (1965) Morphogenesis of ciliature in the physiological and traumatic regennation of Urostyla cristata Jerka-Dziadosz 1964. Acta Protozoologica, 3, 133–142, Plate I.
Jerka-Dziadosz, M. (1972) Cortical development in Urostyla. I. Comparative study on morphogenesis in U. cristata and U. grandis. Acta Protozoologica, 10, 73–100, Plates I–X.
Kahl, A. (1932) Urtiere oder Protozoa I: Wimpertiere oder Ciliata (Infusoria) 3. Spirotricha. Tierwelt Deutschlands, 25, 399–650.
Kimura, M. (1980) A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences. Journal of Molecular Evolution, 16, 111–120.
Kumar, S., Kamra, K. & Sapra, G.R. (2010) Ciliates of the Silent Valley National Park, India: Urostyloid hypotrichs of the region with a note on the habitat. Acta Protozoologica, 9, 339–364.
Kumar, S., Tamura, K. & Nei, M. (2004) MEGA3: Integrated software for molecular evolutionary genetics analysis and sequence alignment. Briefings in Bioinformatics, 5, 150–163.
Lee, S.H. & Yu, K.-M. (2011) Depositional environments of Holocene laminated layers in the core SJ99 collected from the Songjiho Lagoon on the eastern coast of Korea. Journal of the Geological Society of Korea, 47, 123–137 (in Korean with English abstract).
Li, L., Khan, S.N., Ji, D., Shin, M.K. & Berger, H. (2011) Morphology and small subunit (SSU) rRNA gene sequence of the new brackish water ciliate Neobakuella flava n. g., n. sp. (Ciliophora, Spirotricha, Bakuellidae) and SSU rRNA gene sequences of six additional hypotrichs from Korea. Journal of Eukaryotic Microbiology, 58, 339–351.
Loreau, M. & Mouquet, N. (1999) Immigration and the maintenance of local species diversity. The American Naturalist 154, 42–440.
Lynn, D.H. (2008) The ciliated protozoa: Characterization, classification, and guide to the literature. Springer, New York, 605 pp.
Medlin, L., Elwood, H.J., Stickel, S. & Sogin, M.L. (1988) The characterization of enzymatically amplified eukaryotic 16S-like rRNA-coding regions. Gene, 71, 491–499.
Oberschmidleitner, R. & Aescht, E. (1996) Taxonomische Untersuchungen über einige Ciliaten (Ciliophora, Protozoa) aus Belebtschlämmen oberösterreichischer Kläranlagen. Beiträge zur Naturkunde Oberösterreichs, 4, 3–30.
Paiva, T.S., Borges, B.N., Silva-Neto, I.D. & Harada, M.L. (2012) Morphology and 18S rDNA phylogeny of Hemicycliostyla sphagni (Ciliophora, Hypotricha) from Brazil with redefinition of the genus Hemicycliostyla. International Journal of Systematic and Evolutionary Microbiology, 62, 229–241.
Paiva, T.S. & Silva-Neto, I.D. (2006) Pseudourostyla pelotensis sp. nov. (Ciliophora, Stichotrichia, Urostylida): a new psammophilic ciliate from the southern Brazil. Zootaxa, 1247, 43–58.
Posada, D. (2008) jModelTest: Phylogenetic model averaging. Molecular Biology and Evolution, 25, 1253–1256.
Ronquist, F. & Huelsenbeck, J.P. (2003) MrBayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics, 19, 1572–1574.
Sonnenberg, R., Nolte, A.W. & Tautz, D. (2007) An evaluation of LSU rDNA D1-D2 sequences for their use in species identification. Frontiers in zoology, 4, 6.
Tchang, T., Pang, Y. & Zou, S. (1982) A study on morphogenesis of Urostyla cristata. Zoological Research, 3, 1–9.
Wiackowski, K. (1988) Morphology and morphogenesis of a new species in the genus Pseudourostyla (Hypotrichida, Ciliophora). Journal of Natural History, 22, 1085–1094.
Yi, Z. & Song, W. (2011) Evolution of the order Urostylida (Protozoa, Ciliophora): New hypotheses based on multi-gene information and identification of localized incongruence. PLoS ONE, 6, e17471.
Yum, J.-G. (2001) Late quaternary envrionmental changes of the Hwajinpo and Songjiho lagoons on the eastern coast of Korea. Disserttion, Seoul, Yonsei university.