title: Morphological reports on two species of Dexiotricha (Ciliophora, Scuticociliatia), with a note on the phylogenetic position of the genus.
abstract: Two Dexiotricha species (Dexiotricha elliptica nov. comb. and Dexiotricha cf. granulosa), respectively isolated from soil north-west of Riyadh, Saudi Arabia, and freshwater in Shanghai, eastern China, were investigated using standard methods. The species Loxocephalus ellipticus Kahl, 1931 is reclassified here in the genus Dexiotricha and was characterized mainly by constantly showing 16 somatic kineties, three post-oral kineties with the middle one shortened, a contractile vacuole located subcaudally with an excretory pore near the posterior end of somatic kinety 2 and single caudal cilia. A Dexiotricha granulosa-like organism having a subcaudally located contractile vacuole and fewer somatic kineties was designated D. cf. granulosa. The small-subunit rRNA gene (SSU rDNA) sequences of these two species were characterized and their phylogenetic positions based on SSU rDNA sequences were revealed by means of Bayesian inference and maximum-likelihood analysis. Phylogenetic analyses confirmed Dexiotricha as a monophyletic genus and supported its assignment to the order Loxocephalida. However, its family assignment remains unsupported.
authors.affiliation: School of Life Sciences, East China Normal University, Shanghai 200062, PR China.
authors.forename: Xinpeng
authors.initials: X
authors.lastname: Fan
authors.affiliation: Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Saleh A
authors.initials: SA
authors.lastname: Al-Farraj
authors.affiliation: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: School of Life Sciences, East China Normal University, Shanghai 200062, PR China.
authors.forename: Fukang
authors.initials: F
authors.lastname: Gu
mesh_terms: D001499:Bayes Theorem; D002681:China; D005618:Fresh Water / Q000382:microbiology; D016013:Likelihood Functions; D008969:Molecular Sequence Data; D016802:Oligohymenophorea / Q000145:classification* / Q000166:cytology* / Q000235:genetics / Q000302:isolation & purification; D010802:Phylogeny; D054682:Ribosome Subunits, Small, Eukaryotic / Q000235:genetics; D012529:Saudi Arabia; D012988:Soil Microbiology; D014617:Vacuoles; D014871:Water Microbiology