Sanghee Kim

In this study, a new marine urostylid ciliate, Metaurostylopsis antarctica nov. spec. collected from the Antarctic Ocean was investigated using morphological, morphometrical, and molecular methods. Metaurostylopsis antarctica nov. spec. is characterized as follows: slender to ellipsoid form in body shape; two types of cortical granules, ellipsoid large one (type I, yellow-green, 1.5 × 1 μm) in rows along dorsal kineties and cirri, circular small one (type II, colourless, 0.3 μm in diameter) scattered throughout whole body; 19–24 adoral membranelles, 4 frontal cirri, 2–5 frontoterminal cirri, 1 buccal and 2 transverse cirri; 3–5 midventral pairs, 10–15 cirri of midventral row; 1 right and 2 left marginal rows; 3 dorsal kineties; about 43 macronuclear nodules. This new species mainly differs from the congeners by the number of marginal rows (1 vs. 3 or more on right side; 2 vs. 3 or more on left side). In addition, proter’s oral primordium  developed on the right side of the oral cavity (vs. in center of oral cavity), and the rightmost anlage splits into two parts, nam ely, the frontoterminal cirri and a transverse cirrus (vs. only frontoterminal cirri). Inter-specific dissimilarities of the SSU rRNA gene between the congeners range from 3.3 to 4.4%.

The soil ciliate Anteholosticha rectangula nov. spec. was discovered on King George Island in maritime Antarctica. Morphology and the nuclear SSU rDNA sequence were used to describe and infer the phylogenetic position of the new species. Anteholosticha rectangula is morphologically similar to A. bergeri and A. verrucosa, differing primarily by the morphology of the nuclear apparatus and dorsal kineties, respectively. The morphological features of related species are compared and discussed to confirm the validity of the new species. Molecular phylogenetic tree supports the previously reported polyphyly of the genus Anteholosticha.