AUTHOR=Wu Zehao , Liu Mingjian , Ye Tingting , Zhao Xuetong , Wu Fan , Jiang Yaohan , Chen Xiangrui 

TITLE=New contributions to the taxonomy and phylogeny of the ciliate genus Pleuronema (Ciliophora, Scuticociliatia), with descriptions of two new species collected from the subtropical coastal wetlands in China

JOURNAL=Frontiers in Marine Science

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1320684

DOI=10.3389/fmars.2023.1320684

ISSN=2296-7745

ABSTRACT=<p>Ciliates of the genus <italic>Pleuronema</italic> are a speciose and ubiquitous group. Recent studies suggest that there may be a sizable amount of undiscovered species diversity. In the present study, two new <italic>Pleuronema</italic> species have been isolated from the subtropical coastal waters of China and characterized using morphological and taxonomical methods: <italic>Pleuronema pulchra</italic> n. sp. is characterized by a body size of 75–90 × 25–40 µm <italic>in vivo</italic>, 32–48 somatic kineties, four to seven preoral kineties, somatic kinety 1 composed of about 80 kinetids, and membranelle 2a with a single-rowed mid-portion and hook-like posterior portion. <italic>Pleuronema warreni</italic> n. sp. is defined by a body size of 55–80 × 25–45 µm <italic>in vivo</italic>, 35–42 somatic kineties, three to six preoral kineties, somatic kinety 1 with approximately 75 kinetids, and a mid-portion of membranelle 2a that is single-rowed and extremely long (occupying &gt; 75% length of M2a). The phylogenetic analysis of the small subunit ribosomal RNA genes of <italic>Pleuronema</italic> members, including those of the two novel species, shows that the genus <italic>Pleuronema</italic> is a polyphyletic group. Both new species form a cluster with <italic>Pleuronema binucleatum</italic> KT033424, <italic>P. elegans</italic> KF840518, and “<italic>P. coronatum</italic>” JX310014 (identification to be verified). Additionally, we provide an illustrated key for 20 “<italic>coronatum</italic>-type” <italic>Pleuronema</italic> species, including the two new ones.</p>