|Abstract: ||abstract:Parastrombidinopsis minima n. sp. is investigated, using live observations, protargol preparations, and molecular data. In living cells, the ranges of cell length are 85–95 μm, cell width 60–70 μm, and oral diameter 40–50 μm. In protargol-impregnated specimens, cell length ranges between 43 and 71 μm, cell width between 23 and 42 μm, and oral diameter between 13 and 24 μm. The numbers of external oral polykinetids are 12–16 and of somatic kineties are 11–13. There are always two ovoid macronuclei (9–16 × 4–9 μm). Based on the analysis of morphologic data, the new species can be placed in the family Strombidinopsidae, but based on the small subunit rRNA gene sequence data, the Parastrombidinopsis species are more closely associated with strobilidiids and tintinnids.
OLIGOTRICH ciliates are important components of the marine planktonic microbial loop due to their high abundances and growth rates (Pierce and Turner 1992). There is still much to be learned about the taxonomic diversity of oligotrichs, although many new or improved cytological descriptions and classifications of aloricate oligotrichs have appeared, using live observation and modern techniques (e.g. Agatha 2003a, b, 2004; Agatha and Riedel-Lorjé 1997, 1998, 2006; Dale and Lynn 1998; Foissner, Skogstad, and Pratt 1988; Lynn and Montagnes 1988; Lynn, Montagnes, and Small 1988; Lynn et al. 1991; Martin and Montagnes 1993; Montagnes and Lynn 1987, 1991; Montagnes and Taylor 1994; Montagnes, Taylor, and Lynn 1990; Montagnes et al. 1988; Snyder and Ohman 1991; Song 2005; Wilbert and Song 2005; Xu and Song 2006; Xu, Song, and Hu 2005; Xu, Song, and Warren 2006; Xu et al. 2006a, b, 2007). However, the combination of morphological and molecular data provides a better means for species description (Agatha et al. 2005; Jeong et al. 2004; Kim et al. 2005; Modeo et al. 2003).
The genus Parastrombidinopsis was recently established by Kim et al. (2005) with the type species, Parastrombidinopsis shimi. While studying planktonic ciliates of the coastal waters off northeastern Taiwan, we discovered a new Parastrombidinopsis species, which is described below based on morphology, infraciliature, and gene sequences.