Further insights into the phylogeny of two ciliate classes Nassophorea and Prostomatea (Protista, Ciliophora)

Abstract

a b s t r a c tThe Nassophorea and Prostomatea are two of the key classes in understanding the morphological diversification and higher classification of the phylum Ciliophora. However, their phylogenetic relationships with other ciliate groups within the subphylum Intramacronucleata remain elusive. In this study, we investigated the small and large subunit (SSU and LSU) rRNA gene-based phylogeny of these groups with sequences of additional taxa including several key species. The results show that: (1) the class Nassophorea remains polyphyletic, with the microthoracids clustering with the Phyllopharyngea, whereas the nassulids represent a basal group of the CONthreeP superclade in the SSU tree; (2) the Prostomatea is not depicted as a monophyletic group in phylogenetic trees, and the monophyly of this class is marginally rejected by statistical tree topology tests; (3) the nassulid genus Parafurgasonia is more closely related to the family Colpodidiidae than to Furgasonia; (4) Paranassula, which was previously thought to be a nassulid, is phylogenetically related to the oligohymenophorean peniculids in both the SSU and LSU trees; (5) the microthoracid genus Discotricha does not group with the other microthoracids in either SSU or LSU trees; (6) the family Plagiocampidae is closely related to the prostome parasite Cryptocaryon irritans and to the family Urotrichidae in the order Prorodontida; and (7) the family Placidae, represented by Placus salinus, is sister to the family Holophryidae in the order Prorodontida. Based on the present data, we consider the genus Discotricha to be an unclassified taxon within the CONthreeP. We also propose resurrecting the order Paranassulida and classifying it within the subclass Peniculia, class Oligohymenophorea. Primary and secondary structure signatures for higher taxa within Phyllopharyngea and Nassophorea are supplied.

Morphological and molecular characterization of Parafurgasonia zhangi spec. nov. and Chilodonella acuta Kahl, 1931 (Protozoa, Ciliophora), from a soil habitat of Saudi Arabia

“…Furthermore, Chilodonella acuta clusters with its congener Chilodonella uncinata with full support values, which, along with their sequence comparisons, indicates the validity of Chilodonella acuta as a well-outlined and distinctive member of the genus. Our results reveal that P. zhangi is closer to the Colpodidiidae rather than to F. blochmanni, consequently indicating that the Furgasoniidae is possibly not monophyletic, but more data are clearly needed to make a final conclusion, since its hypothesized monophyly was not rejected in previous tests (Zhang et al, 2014). The Colpodidiidae was promoted as an order, Colpodidiida, by Foissner et al (2002), which is mainly characterized by bearing no cyrtos and thus differed from Nassulidae and Furgasoniidae, the two families of the Nassulida.…”

Phylogenetic framework of the systematically confused Anteholosticha–Holosticha complex (Ciliophora, Hypotrichia) based on multigene analysis

“…They inhabit wide range of marine, estuarine and fresh waters, sometimes with great abundance and biomass. Although numerous studies have been performed on the assignments and phylogenetic relationships of species within this group (Berger, 2006(Berger, , 2008Chen et al, 2013a;Corliss, 1979;Fan et al, 2013;Foissner and Stoeck, 2011;Gao et al, 2010Gao et al, , 2013Kim et al, 2013;Lynn, 2008;Pan et al, 2013;de Puytorac, 1994;Singh and Kamra, 2013), incongruences between morphological and gene sequence data have always existed especially in morphologically diverse taxa (Gentekaki et al, 2014;Huang et al, 2012;Lahr et al, 2013;Li et al, 2013;Moreira et al, 2007;Simpson et al, 2006;Zhang et al, 2014). According to Lynn's system (2008), the order Urostylida comprises four families (Pseudokeronopsidae, Pseudourostylidae, Urostylidae, Epiclintidae).…”

“…In order to infer more robust phylogenetic relationships, concatenated phylogenetic analyses of multiple genes have recently been used in different groups of ciliates and other protists Gentekaki et al, 2014;Huang et al, 2012;Lahr et al, 2013;Li et al, 2013;Moreira et al, 2007;Simpson et al, 2006;Zhang et al, 2014). In the present study, we increased taxon representatives and sequenced gene markers other than the SSU-rDNA in order to perform more comprehensive phylogenetic analyses of the Anteholosticha-Holosticha complex and of the order Urostylida.…”

Description and phylogeny of a new prostomatid, Metacystis similis nov. spec. (Protista, Ciliophora) from the East China Sea

“…For the Maximum likelihood (ML) analysis, selection of the best model was computed with the jModeltest program (Darriba et al, 2012). The ML tree was constructed with the PhyML v 2.4.4 program (Zhang Q et al, 2014). The reliability of internal branches was assessed by a nonparametric bootstrap method with 1000 replicates.…”