Systematics and Multi-Gene Phylogeny of the Subfamily Nothoholostichinae (Ciliophora, Hypotrichia), With Integrative Description of a New Marine Species Nothoholosticha luporinii n. sp.

Abstract

Morphogenesis of ciliated protists attracts a lot of attention, because their huge morphological diversity is related to formation of ciliary structures during cell division. In the present work, the morphology and morphogenesis as well as the phylogenetic position of a new, marine hypotrich ciliate, Nothoholosticha luporinii n. sp., were investigated. The new species is characterized by having a combination of the following features: a bicorona whose anterior row contains four frontal cirri and posterior row includes only two cirri, a single buccal cirrus, midventral complex composed of about 30 cirral pairs, one pretransverse cirrus, 3–6 transverse cirri, one left and one right marginal cirral row; three bipolar dorsal kineties; contractile vacuole located in about 2/3 of the body length, two types of cortical granules, and many macronuclear nodules scattered throughout the cytoplasm. The morphogenesis of N. luporinii follows the ontogenetic mode of Pseudokeronopsis, a well-known and closely related genus except that the macronucleus fuses into a single mass in the middle fission stage. Phylogenetic analyses based on the rDNA operon classify Nothoholosticha in the family Pseudokeronopsidae and support the distinctness of the new taxon as well as the monophyletic origin of the subfamily Nothoholostichinae.

Multi-Gene Phylogeny of the Ciliate Genus Trachelostyla (Ciliophora, Hypotrichia), With Integrative Description of Two Species, Trachelostyla multinucleata Spec. nov. and T. pediculiformis (Cohn, 1866)

“…Monophyly of trachelostylids was corroborated not only by morphological data but also by multigene phylogenetic analyses ( Figure 9 ), albeit not by single-gene analyses ( Figure 8 ). Various studies have already shown that concatenation of 18S, ITS1-5.8S-ITS2, and 28S rDNA sequences might lead to better resolved phylogenetic trees in the subclass Hypotrichia than 18S rDNA sequences per se (e.g., Huang et al, 2016 ; Obert and Vd’ačný, 2020 ; Zhang et al, 2020b ; Wang et al, 2021b ). The same applies also to the monophyletic origin of the genus Trachelostyla , which was only indicated in 18S rDNA phylogenies ( Figure 8 ) although well recognizable in the multigene trees ( Figure 9 ).…”

“…nov. and T. pediculiformis pop. 1 were investigated using a combination of detailed in vivo observation and protargol impregnation as described by Zhang et al (2020b) . Morphometric data were obtained from living and protargol-impregnated specimens.…”

“…Extraction of the genomic DNA and PCR amplification of 18S, ITS1-5.8S-ITS2, and 28S rDNA as well as sequencing of T. multinucleata spec. nov. followed our previous study (Zhang et al, 2020b). Conspecific sequences obtained from multiple samples were identical, and therefore, only those derived from the single-cell sample were included in the subsequent phylogenetic analyses.…”

Insights into the phylogeny of the ciliate of class Colpodea based on multigene data

“…Recently, investigations based on multigene trees have been increasingly used for phylogenetic studies and generally produce more robust results than those based on single gene markers (Gao et al, 2013 , 2016 , 2017 ; Sun et al, 2020 ; Wang, Wang, et al, 2017 ; Zhang et al, 2020 ). Multigene analyses usually include nSSU‐rRNA, ITS1‐5.8S‐ITS2 and nLSU‐rRNA genes, which are in the same chromosome (Wang, Wang, et al, 2017 ).…”

Taxonomy and Molecular Phylogeny of Two New Urostylid Ciliates (Protozoa: Ciliophora) From Chinese Wetlands and Establishment of a New Genus

“…Urostylids, with more than 200 described species, are one of the largest groups in the subclass Hypotrichia (Berger, 2006). Studies from the past few decades have revealed that this group is even more diverse than previously thought, and many new species are likely awaiting discovery (Berger, 2006;Jiang et al, 2013;Jo et al, 2015;Kim et al, 2016;Song and Shao, 2017;Chen et al, 2018Chen et al, , 2020Zhu et al, 2019;Shao et al, 2020;Xu et al, 2020;Zhang et al, 2020a). In addition, some classifications at the family and genus levels within this group (e.g., Bakuellidae Jankowski, 1979 andAnteholosticha Berger, 2003), and their systematic relationships, remain confusing (for reviews, see Berger, 2006;Huang et al, 2014;Lyu et al, 2015Lyu et al, , 2018Moon et al, 2020;Zhang et al, 2020b).…”