Two marine urostylid ciliates, Caudiholosticha marina sp. nov. and Nothoholosticha flava sp. nov., isolated from intertidal sediment in the Yellow Sea, are investigated using morphological and small subunit rDNA phylogenetic analyses. Caudiholosticha marina is 210-310 μm × 40-55 μm in vivo, and has 10-20 macronuclear nodules, 23-37 midventral cirral pairs extending to 5-8 transverse cirri, and two caudal cirri. It differs from congeners by its marine habitat, larger size, macronuclear arrangement pattern and high number of midventral pairs. Molecular phylogenetic analyses indicate a polyphyly of Caudiholosticha. Nothoholosticha flava is yellow to brownish and 240-320 μm × 40-60 μm sized, and has a bipartite adoral zone, six frontal cirri in atypical bicorona, usually four frontoterminal, one buccal and 5-7 transverse cirri and 28-54 midventral pairs. Phylogenetic analyses allocate N. flava as sister of N. fasciola, type of the genus. The two Nothoholosticha species differ distinctly by the presence/absence of frontoterminal cirri, a feature often used to define genera in the Hypotrichia. However, the SSU rDNA sequence similarity between these two species is 99.3%, which weakens the justification for separating the new isolate at genus level. The taxonomic significance of frontoterminal cirri is discussed based on morphological and molecular data.
Keywords: SSU rDNA; Taxonomy; Urostylida; new species.
© 2015 The Author(s) Journal of Eukaryotic Microbiology © 2015 International Society of Protistologists.