Taxonomy and SSU rDNA-Based Phylogeny of Two Heterotrich Ciliates (Ciliophora, Heterotrichea) Collected From Subtropical Wetlands of China, Including the Description of a New Species, Linostomella pseudovorticella n. sp.

Abstract

The Heterotrichea Stein, 1859 are a group of ciliated protists (single-celled eukaryotes) that occur in a wide variety of aquatic habitat where they play important roles in the flow of nutrients and energy within the microbial food web. Many species are model organisms for research in cytology and regenerative biology. In the present study, the morphology and phylogeny of two heterotrich ciliates, namely, Linostomella pseudovorticella n. sp. and Peritromus kahli Villeneuve-Brachon, 1940, collected from subtropical wetlands of China, were investigated using morphological and molecular methods. L. pseudovorticella n. sp. differs from its only known congener, Linostomella vorticella Ehrenberg, 1833 Aescht in Foissner et al., 1999, by having more ciliary rows (48–67, mean about 56 vs. 26–51, mean about 42) and its small-subunit (SSU) rDNA sequence, which shows a 15-bp divergence. Although P. kahli has been reported several times in recent decades, its infraciliature has yet to be described. A redescription and improved diagnosis of this species based on a combination of previous and present data are here supplied. Phylogenetic analyses based on SSU rDNA sequences revealed that the genus Linostomella is positioned within Condylostomatidae, and Peritromidae is sister to Climacostomidae with relatively low support, and the family Spirostomidae is the root branch of the class Heterotrichea.

Exploring the biogeography, morphology, and phylogeny of the condylostomatid ciliates (Alveolata, Ciliophora, Heterotrichea), with establishment of four new Condylostoma species and a revision including redescriptions of five species found in China

“…Through this comprehensive examination, the results are summarized as follow: (1) a total of 30 valid species were recognized, four of which are new (Fig. 3 (Foissner 2016;Foissner et al 2002); (4) three nominal Condylostoma species, C. stagnale, C. vastum, and C. vorticella, have been or should be transferred to Linostomella (Chi et al 2020b;Jin et al 2021).…”

“…The family Condylostomatidae is a relatively well-studied family within the Heterotrichea, and several studies on the diversity of its five genera, Chattonidium Villeneuve-Brachon, 1937, Condylostentor Jankowski, 1978, Condylostoma Bory de Saint-Vincent, 1824, Condylostomides da Silva Neto, 1994, and Linostomella Aescht in Foissner et al, 1999, have been reported in recent years (Chen et al 2007;Chi et al 2020b;Fernandes et al 2015;Jin et al 2021;Kim et al 2012;Modeo et al 2006;Shao et al 2006;Yan et al 2015). The type genus, Condylostoma, is the most speciose of these genera and is commonly found in brackish or marine habitats.…”