Two New Marine Ciliates, Caryotricha rariseta n. sp. and Discocephalus pararotatorius n. sp. (Ciliophora, Spirotrichea), with Phylogenetic Analyses Inferred from the Small Subunit rRNA Gene Sequences

Abstract

The morphology, infraciliature, and molecular phylogeny of two novel spirotrich ciliates, Caryotricha rariseta n. sp. and Discocephalus pararotatorius n. sp., isolated from coastal waters of China, were investigated. Caryotricha rariseta n. sp. differs from its congeners mainly in possessing seven sparsely ciliated cirral rows that are conspicuously shortened posteriorly and three transverse cirri aligned in a row. Discocephalus pararotatorius n. sp. is characterized by the conspicuous spine-like dorsal cilia, one extra (endoral?) membrane, and seven frontal, six ventral, and seven posterolateral marginal cirri. The small subunit rRNA gene was sequenced for both species. Complete SSU rRNA gene sequences of two Caryotricha spp. (including C. rariseta n. sp.) and two Discocephalus spp. (including D. pararotatorius n. sp.), along with those of 40 other ciliates, were used to determine their molecular phylogeny using maximum likelihood, neighbor joining and maximum parsimony analyses. The two Caryotricha species cluster with Kiitricha marina in the well-supported Protohypotrichia clade that is basal to the main spirotrich assemblage. The two discocephalids form a clade that is sister to the Hypotrichia.

The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)

“…Historically, the members of this group were believed to be a primordial assemblage within the Hypotrichia or ancestral forms of euplotids 4 19 20 33 . This hypothesis has received increasing support, both by the addition of more gene sequence data 34 41 and by the recognition of various unique morphological and morphogenetic characters 42 43 . In the present study, the addition of newly sequenced LSU rDNA, 5.8S rDNA, and alpha-tubulin genes invariably resulted in the protohypotricheans clustering in a well-supported clade that is basal to the hypotrichs and euplotids ( Figs 1A and 2 ).…”

Molecular Phylogeny and Taxonomy of Two Novel Brackish Water Hypotrich Ciliates, with the Establishment of a New Genus, Antiokeronopsis gen. n. (Ciliophora, Hypotrichia)

“…Drawings were made with the help of camera lucida (Jiang et al. ). Terminology is according to Berger ().…”

“…Counts and measurements of stained specimens were performed with an ocular micrometer. Drawings were made with the help of camera lucida (Jiang et al 2013b). Terminology is according to Berger (2006).…”

Taxonomy and phylogeny of two species of the genus Deviata (Protista, Ciliophora) from China, with description of a new soil form, Deviata parabacilliformis sp. nov.

“…Morphological identification is challenging for these organisms, especially for the highly complicated hypotrichs. This situation is being improved, however, as a result of staining techniques which can reveal the infraciliature and other characteristics precisely (Chen et al , 2013a, b; Jiang et al , 2013a, b; Li et al , 2013; Pan et al , 2013; Shao et al , 2013a; Singh & Kamra, 2013; Singh et al , 2013; Fan et al , 2014; Gao & Katz, 2014; Huang et al , 2014; Jung et al , 2014).…”