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Systematics and Molecular Phylogeny of the Ciliate Genus Pseudokeronopsis (Ciliophora, Hypotrichia)
Author(s) -
Li Ju,
Zhan Zifeng,
Xu Kuidong
Publication year - 2017
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12420
Subject(s) - biology , ciliate , systematics , phylogenetic tree , interspecific competition , intraspecific competition , phylogenetics , molecular phylogenetics , dna barcoding , sister group , zoology , genus , evolutionary biology , botany , taxonomy (biology) , clade , ecology , genetics , gene
A still challenging study on ciliate systematics is to clarify the taxonomic and phylogenetic confusions of the fascinating pigmented Pseudokeronopsis species because of their high interspecific similarities. We evaluated the identities and internal relationships within Pseudokeronopsis based on morphological descriptions in combination with the 18S and ITS ‐5.8S rDNA genetic distances, ITS 2 secondary structures and phylogenetic analyses. Results showed that (1) Pseudokeronopsis pararubra , a species ever synonymized as Pseudokeronopsis carnea , is a valid species; (2) most Chinese populations identified as Pseudokeronopsis rubra represent a new species namely Pseudokeronopsis songi sp. nov.; (3) within Pseudokeronopsis , P. carnea branched early, while P. songi sp. nov., P. flava , and P. erythrina showed close relationships and formed a sister clade with P. pararubra ; (4) compared to 18S and ITS 2 rDNA , ITS ‐5.8S rDNA is more suitable for separating Pseudokeronopsis species, with pairwise distances of 0–0.0441 at the intraspecific level and 0.0635–0.1150 at the interspecific level; and (5) the core structure of Pseudokeronopsis ITS 2 includes three helices, with helix III being the longest and showing an identical pattern in conspecific populations and small differences among species. Based on the evaluation, we clarify all misidentified and dubious 18S and ITS ‐5.8S rDNA sequences of Pseudokeronopsis in GenBank.