title: Morphology and morphogenesis of a soil ciliate, Rigidohymena candens (Kahl, 1932) Berger, 2011 (Ciliophora, Hypotricha, Oxytrichidae), with notes on its molecular phylogeny based on small-subunit rDNA sequence data.
abstract: The morphology and morphogenesis of the stylonychine hypotrich Rigidohymena candens (Kahl, 1932) Berger, 2011, isolated from garden soil in Qingdao, China, were investigated using live observation and protargol impregnation methods. The Qingdao isolate possesses all diagnostic morphological characters of R. candens. The main events during binary fission are as follows: (i) the proter retains the parental adoral zone of membranelles entirely, whereas the old undulating membranes dedifferentiate into an anlage that gives rise to the leftmost frontal cirrus and the new undulating membranes of the proter; (ii) five streaks of fronto-ventral-transverse cirral anlagen are segmented in the pattern 3 : 3 : 3 : 4 : 4 from left to right, which form two frontal, four frontoventral, one buccal, five ventral and five transverse cirri, respectively; (iii) dorsal morphogenesis is in the typical Oxytricha pattern; (iv) three caudal cirri are formed, one at the posterior end of each of dorsal kineties 1, 2 and 4; and (v) the postoral ventral cirrus V/3 is not involved in primordia formation. The morphological and morphogenetic observations and phylogenetic analyses based on the small-subunit rDNA sequence data support the validity of Rigidohymena Berger, 2011 and its systematic position in the subfamily Stylonychinae.
authors: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors: Xumiao
authors: X
authors: Chen
authors: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors: Ying
authors: Y
authors: Yan
authors: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors: Xiaozhong
authors: X
authors: Hu
authors: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors: Mingzhuang
authors: M
authors: Zhu
authors: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors: Honggang
authors: H
authors: Ma
authors: Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
authors: Alan
authors: A
authors: Warren
mesh_terms: D002681:China; D004275:DNA, Ribosomal / Q000235:genetics; D016810:Hypotrichida / Q000145:classification* / Q000166:cytology* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010802:Phylogeny; D012987:Soil
chemical_list: D004275:DNA, Ribosomal; D012987:Soil