Abstract
The small subunit rRNA (SSU rRNA) gene for six marine stichotrichs,
Pseudokeronopsis carnea,
P. flava,
Holosticha heterofoissneri,
H.
diademata,
H. bradburyae and
Anteholosticha manca, was sequenced and characterized. Using this molecular information, the phylogenetic positions of three related genera,
Pseudokeronopsis,
Holosticha and
Anteholosticha were determined. The results indicate that the family Urostylidae is clearly separated from the family Pseudokeronopsidae. The present phylogenetic analyses unambiguously placed
Pseudokeronopsis close to
Holosticha, and support the conclusion that these genera should be regarded as the members of the order Urostylidae within the stichotrich clade. Furthermore, the results of this study also support the monophyly of the genus
Pseudokeronopsis, the redefinition of
Holosticha s. str. and the placement of
Anteholosticha in a clade separate from
Holosticha.