Parabirojimia multinucleata spec. nov. and Anteholosticha scutellum (Cohn, 1866) Berger, 2003, marine ciliates (Ciliophora, Hypotrichida) from tropical waters in southern China, with notes on their small-subunit rRNA gene sequences

Abstract

Few studies using modern methods have been carried out on ciliated protozoa in tropical marine waters. In the present work, two hypotrichs, Parabirojimia multinucleata spec. nov. and Anteholosticha scutellum (Cohn, 1866) Berger, 2003, collected from Daya Bay in southern China, were investigated morphologically. P. multinucleata is distinguished by the following combination of characters: slender body, without a snout-like protrusion in the frontal field, and about 50 macronuclear nodules. The poorly known A. scutellum has never been investigated using modern methods; hence, a redescription is needed. During the present study, observations of specimens in vivo and following protargol impregnation revealed new information concerning structures such as the cortical granules and the infraciliature. A redescription and improved diagnosis are supplied based on the China population. The small-subunit (SSU) rRNA gene was sequenced for both organisms and comparisons with those of similar congeners clearly support the findings based on morphological studies.

Phylogenetic positions and taxonomic assignments of the systematically controversial genera,Spirotrachelostyla,UroleptopsisandTunicothrix(Protozoa, Ciliophora, Stichotrichia) based on small subunit rRNA gene sequences

“…In the present topological analyses, Tunicothrix and Parabirojimia formed a clearly divergent, monophyletic clade, basal to other hypotrichs and distant from the Urostylidae, which was maximally supported in all of our SSU rRNA trees (Figs 9, 10). These results correspond as well to the extreme morphological and morphogenetic similarities between both genera (Chen et al, 2010).…”

“…Xu et al (2006), as they described the new genus Tunicothrix, assigned it to the family Urostylidae while also pointing out that it and Parabirojimia form a morphologically distinct group with an atypical, bipartite pattern of adoral ciliature. Also, both genera have very similar patterns of somatic ciliature, with one left and two or more right marginal rows, midventral pairs restricted to the level of the oral region, short and inconspicuous midventral rows continued as a long ventral row, several right marginal rows and presence of transverse cirri Lin & Song, 2004;Chen et al, 2010).…”

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

“…To date, about 40 species have been assigned to Anteholosticha, and new species are still being characterized and classified into this genus (Fan et al, 2014a;Park et al, 2013). The morphological hypothesis that Anteholosticha is not a monophyletic genus has been constantly supported by small subunit ribosomal RNA (SSU-rRNA) gene phylogenies (e.g., Chen et al, 2010;Park et al, 2013;Shao et al, 2011;Xu et al, 2011). As a first separation of the speciose genus Anteholosticha, three species (A. scutellum, A. petzi, A. warreni) with a roughly U-shaped pattern of transverse cirri, were transferred to a new genus Arcuseries by Huang et al (2014).…”

Evolution of discocephalid ciliates: Molecular, morphological and ontogenetic data support a sister group of discocephalids and pseudoamphisiellids (Protozoa, Ciliophora) with establishment of a new suborder Pseudoamphisiellina subord. n.

“…Morphologically, Pseudoamphisiella is considerably divergent from typical urostylid hypotrichs (e.g., Holosticha, pseudokeronopsids, and Urostyla) be-cause the cirri of its midventral rows are arranged in a separate, non-zig-zag pattern, and especially as there are/is no migrating cirri/row (frontoterminal cirri/row) during morphogenesis, which are formed characteristically from the posterior-most (right-most) FVT-cirral anlage [40]. In addition, the caudal cirri, which are lacking in all typical urostylids, are formed uniquely from the posterior end of each dorsal kinety anlage and the right marginal row has a unique de novo origin (i.e., appears as an independent anlage neighboring other FTV-primordia vs. being developed always intrakinetally within the parental structure in all other known hypotrichs) [12,32,38,[41][42][43][44][45]. All these features cast strong doubt on the classification of Pseudoamphisiella, and therefore the family Pseudoamphisiellidae, among the urostylid hypotrichs.…”