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.

Didi Jin,Xiangrui Chen,Tingting Ye,Saleh A Al-Farraj,Jie Huang,Xuetong Zhao,Alan Warren

doi:10.3389/fmicb.2021.719360

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.

Highlights

Ciliated protists are a morphologically diverse and highly specialized group of microbial eukaryotes that constitute an important component of the microbial food web (Azam et al, 1983; Dolan et al, 2012; Miao et al, 2020; Zhao et al, 2020; Liu et al, 2021)
The genus Linostomella was erected for L. vorticella, in 1999, the type species by monotypy
Three populations of L. vorticella have previously been reported with data on the infraciliature, and all three overlap in terms of the number of somatic kineties, i.e., 39–45 in a Rheinland-Pfalz population, 26–45 in a Salzburg population, and 37–51 in a Qingdao population (Packroff and Wilbert, 1991; Foissner et al, 1999; Chi et al, 2020)

Summary

INTRODUCTION

Ciliated protists (ciliates) are a morphologically diverse and highly specialized group of microbial eukaryotes that constitute an important component of the microbial food web (Azam et al, 1983; Dolan et al, 2012; Miao et al, 2020; Zhao et al, 2020; Liu et al, 2021). Some genera are not familiar because they have few species and/or they are difficult to collect, e.g., Linostomella Aescht in Foissner et al, 1999, Chattonidium Villeneuve, 1937, and Peritromus Stein, 1863 (Rosati et al, 2004; Modeo et al, 2006; Chi et al, 2020, 2021). 16 nominal species of Peritromus have been reported, detailed morphological information and molecular data are available for only two, i.e., Peritromus faurei Kahl, 1932 and Peritromus kahli Villeneuve-Brachon, 1940 (Song and Wilbert, 1997; Rosati et al, 2004; Miao et al, 2009). P. kahli, were isolated from subtropical wetlands in Ningbo, China (Figure 1) Their taxonomy and phylogeny were investigated based on detailed morphological information and small-subunit (SSU) rDNA sequences

MATERIALS AND METHODS

RESULTS

DISCUSSION

DATA AVAILABILITY STATEMENT