Biodiversity of oligotrich ciliates in the South China Sea: description of three new Strombidium species (Protozoa, Ciliophora, Oligotrichia) with phylogenetic analyses

Abstract

The morphology and small subunit ribosomal RNA (SSU rRNA) gene sequences of three new species of ciliates in the genus Strombidium are recorded: S. paracapitatum sp. nov., S. cuneiforme sp. nov., and S. caudispina sp. nov. Strombidium paracapitatum sp. nov. is characterized by having a prominent and transparent apical protrusion and two types of extrusomes. Strombidium cuneiforme sp. nov. differs from its congeners in the combination of its long conical body shape, eyespot and elongated tail. Strombidium caudispina sp. nov. is recognized by its posterior spine and short ventral kinety. In SSU rRNA gene trees, all members of the genus Strombidium cluster into three separate groups. The first group is composed of nine Strombidium species including S. cuneiforme sp. nov., plus Williophrya maedai. The second group consists of S. paracapitatum sp. nov., S. caudispina sp. nov. and three congeners. The third group comprises S. conicum and S. chlorophilum.

http://zoobank.org/urn:lsid:zoobank.org:pub:25871A6B-772A-4D26-9940-ACE2B5F1EA07

Key words:

• ciliates
• new species
• oligotrich
• South China Sea
• SSU rRNA gene
• Strombidiidae
• Strombidium

Acknowledgements

This work was supported by the Natural Science Foundation of China (project numbers: 31430077, 41376141) and the International Research Group Program (IRG14-22), Deanship of Scientific Research, King Saud University. We appreciate guidance on correcting English provided by Dr David J. S. Montagnes, at Liverpool University, UK. Many thanks are also given to Professor Xiaofeng Lin (SCNU) for her institutional help.

Disclosure statement

No potential conflict of interest was reported by the authors.

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