Journal of Ocean University of China

, Volume 17, Issue 5, pp 1231–1242 | Cite as

Taxonomic Clarification of A Well-Known Pathogenic Scuticociliate, Miamiensis avidus Thompson & Moewus, 1964 (Ciliophora, Scuticociliatia)

  • Mingzhen Ma
  • Borong Lu
  • Xinpeng Fan
  • Yuhong ShiEmail author
  • Xiangrui ChenEmail author


Miamiensis avidus Thompson & Moewus, 1964, is a cosmopolitan and well-known marine pathogenic ciliated protist. However, the taxonomy of this species up to now has remained controversial, especially with respect to the validity of the morphologically similar species, Philasterides dicentrarchi, which was considered as a junior synonym of M. avidus. In this study, a population of M. avidus was collected from the skin of pharaoh cuttlefish (Sepia pharaonis) cultured near the East China Sea, Ningbo, China and its morphology and phylogeny were investigated in detail based on living characters, infraciliature, small subunit (SSU) rDNA and ITS1-5.8S-ITS2 region sequences. In addition, the morphometrics of a previously reported free-living population, collected from the Bohai Sea, were rechecked and analyzed. We compared the present two isolates with all historic populations of M. avidus and P. dicentrarchi, and found that their morphological characters were either highly similar or exactly identical, indicating that they are the same morphospecies. However, the phylogenetic analyses based on SSU rDNA or ITS1-5.8S-ITS2 region sequences revealed that most M. avidus and P. dicentrarchi populations formed one clade, and the two isolates of M. avidus from Weifang and American Type Culture Collection clustered in another clade, which indicated that there might be cryptic species in Miamiensis avidus.

Key words

Miamiensis avidus morphology phylogeny SSU rDNA synonym ITS1-5.8S-ITS2 region 


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This work was supported by the National Natural Science Foundation of China (No. 31572230), the Open Fund of Zhejiang Provincial Top Key Discipline of Aquaculture in Ningbo University (No. xkzsc1417), the K. C. Wong Magna Fund in Ningbo University, and the Scientific Research Foundation of Graduate School of Ningbo University. We are very grateful to Dr. Jie Huang (Institute of Hydrobiology, Chinese Academy of Sciences) for her help with the phylogenetic analysis.


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Copyright information

© Science Press, Ocean University of China and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.School of Marine SciencesNingbo UniversityNingboChina
  2. 2.Institute of Evolution and Marine BiodiversityOcean University of ChinaQingdaoChina
  3. 3.School of Life SciencesEast China Normal UniversityShanghaiChina

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