Taxonomy and phylogeny of Pseudovorticella littoralis sp. n. and P. alani sp. n. (Ciliophora: Peritrichia) from coastal waters of southern China

The morphology, infraciliature, and silverline system of two peritrich ciliates, Pseudovorticella littoralis sp. n. and P. alani sp. n., isolated from coastal waters of southern China, were investigated based on both living and silver-stained specimens. Pseudovorticella littoralis sp, n. is characterized by the following combination of characters: cell inverted cone-shaped; contractile vacuole ventral; 1-shaped macronucleus; infundibular polykinety 3 with two kinetosome rows of equal length; 19-26 silverlines from peristome to trochal band and 5-14 from trochal band to scopula. Pseudovorticella alani sp. n, is characterized by: cell inverted bell-shaped; contractile vacuole ventral; 1-shaped tnacronucleus recurved almost forming a loop; infundibular polykinety 3 with three kinetosome rows, outer two rows longer than inner one; 48-61 silverlines between peristome and aboral trochal band, and 12-20 between aboral trochal band and scopula. The SSU rDNA sequences of both new species are reported and their genetic distances with congeners and phylogenetic relationships are investigated. Pseudovorticella and Epicarchesium cluster into two subclades with low support values. One subclade contains nearly all the available sequences of Pseudovorticella and Epicarchesium. Another one contains P mondata and E. pectinatum. This calls on the need of a generic re-classification of Pseudovorticella and Epicarchesium based on more morphological and molecular data. (C) 2019 Elsevier GmbH. All rights reserved.