Felipe González, Ana Paula deLamas Fernández, JesúsSueiro Benavides, Rosa AnaFolgueira López, IriaLeiro Vidal, José Manuel2019-01-302019-01-302017-09DE Felipe AP, Lamas J, Sueiro RA, Folgueira I, Leiro JM. (2017). New data on flatfish scuticociliatosis reveal that Miamiensis avidus and Philasterides dicentrarchi are different species. Parasitology 29:1-18. doi: 10.1017/S00311820170007490031-1820http://hdl.handle.net/10347/18170This article has been published in a revised form in Parasitology [http://doi.org/10.1017/S0031182017000749]. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works. © 2017 Cambridge University PressScuticociliatosis is a severe disease in farmed flatfish. However, the causative agent is not always accurately identified. In this study, we identified two isolates of scuticociliates from an outbreak in cultured fine flounder Paralichthys adspersus. Scuticociliate identification was based on morphological data, examination of life stages and the use of molecular approaches. The isolates were compared with a strain of Philasterides dicentrachi from turbot Scophthalmus maximus and with a strain deposited in the American Type Culture Collection as Miamiensis avidus ATCC® 50180™. The use of morphological, biological and molecular methods enabled us to identify the isolates from the fine flouder as P. dicentrarchi. Comparison of P. dicentrachi isolates and M. avidus revealed some differences in the buccal apparatus. Unlike P. dicentrarchi, M. avidus has a life cycle with three forms: macrostomes (capable of feeding on P. dicentrarchi), microstomes and tomites. Additionally, we found differences in the 18S rRNA and α- and β-tubulin gene sequences, indicating that P. dicentrarchi and M. avidus are different species. We therefore reject the synonymy/conspecificity of the two taxa previously suggested. Finally, we suggest that a combination of morphological, biological, molecular (by multigene analysis) and serological techniques could improve the identification of scuticociliates parasites in fisheng© Cambridge University Press 2017. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative worksParalichthys adspersusScophthalmus maximusScuticociliatesSSUrRNA geneα- β-tubulin genejournal article10.1017/S00311820170007491469-8161open access