Morphological, Molecular, and Growth Characteristics of a Cryptic Species, n. sp. (Alveolata: Ciliophora: Oligotrichida).

A new marine planktonic ciliate from Taiwan, sp. n., is described based on live observations, protargol staining, and molecular data. Its morphological characters are similar to those of Claparède and Lachmann, 1859 sensu Song et al., 2000 but differ from sensu Fauré-Fremiet, 1912 and sensu Fauré-Fremiet and Ganier, 1970 by several morphological characters. The 18S rRNA gene sequences of the two forms display 76 base pair differences (about 5%), indicating that they should be considered separate species. The highest observed specific growth rates of in culture were 1.79 day over 1 day and 1.52 day over 2 days, both starting at day 5. Bacteria appear to be an important food resource for the cultivation of this medium-sized oligotrich ciliate. This and other recent studies suggest that cryptic species may be common in the genus , and an integrative approach including morphological, ecological, and molecular data should be used to address this question.