Integrative taxonomy and molecular phylogeny of three poorly known tintinnine ciliates, with the establishment of a new genus (Protista; Ciliophora; Oligotrichea)

Rui Wang; Yang Bai; Tao Hu; Dapeng Xu; Toshikazu Suzuki; Xiaozhong Hu

doi:10.1186/s12862-021-01831-8

Integrative taxonomy and molecular phylogeny of three poorly known tintinnine ciliates, with the establishment of a new genus (Protista; Ciliophora; Oligotrichea)

BMC Ecol Evol. 2021 Jun 9;21(1):115. doi: 10.1186/s12862-021-01831-8.

Authors

Rui Wang^{1

2

3}, Yang Bai^{1

2}, Tao Hu⁴, Dapeng Xu⁵, Toshikazu Suzuki³, Xiaozhong Hu^{6

7}

Affiliations

¹ College of Fisheries, & Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China.
² Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
³ Faculty of Fisheries, Nagasaki University, 1‑14 Bunkyo-machi, Nagasaki, 852‑8521, Japan.
⁴ Laboratory of Protozoology, Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, South China Normal University, Guangzhou, 510631, China.
⁵ State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China.
⁶ College of Fisheries, & Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China. xiaozhonghu@ouc.edu.cn.
⁷ Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China. xiaozhonghu@ouc.edu.cn.

Abstract

Background: The taxonomic classification of the suborder Tintinnina Kofoid & Campbell, 1929, a species-rich group of planktonic ciliated protistans with a characteristic lorica, has long been ambiguous largely due to the lack of cytological and molecular data for most species. Tintinnopsis is the largest, most widespread, and most taxonomically complex genus within this group with about 170 species occurring in nearshore waters. Previous molecular phylogenetic studies have revealed that Tintinnopsis is polyphyletic.

Results: Here we document the live morphology, infraciliature, gene sequences, and habitat characteristics of three poorly known tintinnine species, viz. Tintinnopsis karajacensis Brandt, 1896, Tintinnopsis gracilis Kofoid & Campbell, 1929, and Tintinnopsis tocantinensis Kofoid & Campbell, 1929, isolated from the coastal waters of China. Based on a unique cytological feature (i.e., an elongated ciliary tuft with densely arranged kinetids) in the former two species, Antetintinnopsis gen. nov. is erected with Antetintinnopsis hemispiralis (Yin, 1956) comb. nov. (original combination: Tintinnopsis hemispiralis Yin, 1956) designated as the type species. Moreover, A. karajacensis (Brandt, 1896) comb. nov. (original combination: Tintinnopsis karajacensis Brandt, 1896) and A. gracilis (Kofoid & Campbell, 1929) comb. nov. (original combination: Tintinnopsis gracilis Kofoid & Campbell, 1929) are placed in a highly supported clade that branches separately from Tintinnopsis clades in phylogenetic trees based on SSU rDNA and LSU rDNA sequence data, thus supporting the establishment of the new genus. One other species is assigned to Antetintinnopsis gen. nov., namely A. subacuta (Jörgensen, 1899) comb. nov. (original combination Tintinnopsis subacuta Jörgensen, 1899).

Conclusions: The findings of the phylogenetic analyses support the assertion that cytological characters are taxonomically informative for tintinnines. This study also contributes to the broadening of our understanding of the tintinnine biodiversity and evolution.

Keywords: Biodiversity; Tintinnina; loricate ciliates; new combination; new genus; rDNA.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biodiversity
Ciliophora* / genetics
DNA, Ribosomal / genetics
Phylogeny
Plankton

Substances

DNA, Ribosomal

Grants and funding

41776133/National Natural Science Foundation of China